Merge branch 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull VFS splice updates from Al Viro:
 "There's a bunch of branches this cycle, both mine and from other folks
  and I'd rather send pull requests separately.

  This one is the conversion of ->splice_read() to ITER_PIPE iov_iter
  (and introduction of such). Gets rid of a lot of code in fs/splice.c
  and elsewhere; there will be followups, but these are for the next
  cycle...  Some pipe/splice-related cleanups from Miklos in the same
  branch as well"

* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  pipe: fix comment in pipe_buf_operations
  pipe: add pipe_buf_steal() helper
  pipe: add pipe_buf_confirm() helper
  pipe: add pipe_buf_release() helper
  pipe: add pipe_buf_get() helper
  relay: simplify relay_file_read()
  switch default_file_splice_read() to use of pipe-backed iov_iter
  switch generic_file_splice_read() to use of ->read_iter()
  new iov_iter flavour: pipe-backed
  fuse_dev_splice_read(): switch to add_to_pipe()
  skb_splice_bits(): get rid of callback
  new helper: add_to_pipe()
  splice: lift pipe_lock out of splice_to_pipe()
  splice: switch get_iovec_page_array() to iov_iter
  splice_to_pipe(): don't open-code wakeup_pipe_readers()
  consistent treatment of EFAULT on O_DIRECT read/write

drivers/char/virtio_console.c

@@ -889,7 +889,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 		return 0;
 
 	/* Try lock this page */
-	if (buf->ops->steal(pipe, buf) == 0) {
+	if (pipe_buf_steal(pipe, buf) == 0) {
 		/* Get reference and unlock page for moving */
 		get_page(buf->page);
 		unlock_page(buf->page);

drivers/staging/lustre/lustre/llite/file.c

@@ -1138,10 +1138,6 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
 			range_lock_init(&range, *ppos, *ppos + count - 1);
 
 		vio->vui_fd  = LUSTRE_FPRIVATE(file);
-		vio->vui_io_subtype = args->via_io_subtype;
-
-		switch (vio->vui_io_subtype) {
-		case IO_NORMAL:
 		vio->vui_iter = args->u.normal.via_iter;
 		vio->vui_iocb = args->u.normal.via_iocb;
 		/*
@@ -1163,19 +1159,9 @@ ll_file_io_generic(const struct lu_env *env, struct vvp_io_args *args,
 			range_locked = true;
 		}
 		down_read(&lli->lli_trunc_sem);
-			break;
-		case IO_SPLICE:
-			vio->u.splice.vui_pipe = args->u.splice.via_pipe;
-			vio->u.splice.vui_flags = args->u.splice.via_flags;
-			break;
-		default:
-			CERROR("Unknown IO type - %u\n", vio->vui_io_subtype);
-			LBUG();
-		}
 		ll_cl_add(file, env, io);
 		result = cl_io_loop(env, io);
 		ll_cl_remove(file, env);
-		if (args->via_io_subtype == IO_NORMAL)
 		up_read(&lli->lli_trunc_sem);
 		if (range_locked) {
 			CDEBUG(D_VFSTRACE, "Range unlock [%llu, %llu]\n",
@@ -1235,7 +1221,7 @@ static ssize_t ll_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	if (IS_ERR(env))
 		return PTR_ERR(env);
 
-	args = ll_env_args(env, IO_NORMAL);
+	args = ll_env_args(env);
 	args->u.normal.via_iter = to;
 	args->u.normal.via_iocb = iocb;
 
@@ -1259,7 +1245,7 @@ static ssize_t ll_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	if (IS_ERR(env))
 		return PTR_ERR(env);
 
-	args = ll_env_args(env, IO_NORMAL);
+	args = ll_env_args(env);
 	args->u.normal.via_iter = from;
 	args->u.normal.via_iocb = iocb;
 
@@ -1269,31 +1255,6 @@ static ssize_t ll_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 	return result;
 }
 
-/*
- * Send file content (through pagecache) somewhere with helper
- */
-static ssize_t ll_file_splice_read(struct file *in_file, loff_t *ppos,
-				   struct pipe_inode_info *pipe, size_t count,
-				   unsigned int flags)
-{
-	struct lu_env      *env;
-	struct vvp_io_args *args;
-	ssize_t	     result;
-	int		 refcheck;
-
-	env = cl_env_get(&refcheck);
-	if (IS_ERR(env))
-		return PTR_ERR(env);
-
-	args = ll_env_args(env, IO_SPLICE);
-	args->u.splice.via_pipe = pipe;
-	args->u.splice.via_flags = flags;
-
-	result = ll_file_io_generic(env, args, in_file, CIT_READ, ppos, count);
-	cl_env_put(env, &refcheck);
-	return result;
-}
-
 int ll_lov_setstripe_ea_info(struct inode *inode, struct dentry *dentry,
 			     __u64 flags, struct lov_user_md *lum,
 			     int lum_size)
@@ -3267,7 +3228,7 @@ struct file_operations ll_file_operations = {
 	.release	= ll_file_release,
 	.mmap	   = ll_file_mmap,
 	.llseek	 = ll_file_seek,
-	.splice_read    = ll_file_splice_read,
+	.splice_read    = generic_file_splice_read,
 	.fsync	  = ll_fsync,
 	.flush	  = ll_flush
 };
@@ -3280,7 +3241,7 @@ struct file_operations ll_file_operations_flock = {
 	.release	= ll_file_release,
 	.mmap	   = ll_file_mmap,
 	.llseek	 = ll_file_seek,
-	.splice_read    = ll_file_splice_read,
+	.splice_read    = generic_file_splice_read,
 	.fsync	  = ll_fsync,
 	.flush	  = ll_flush,
 	.flock	  = ll_file_flock,
@@ -3296,7 +3257,7 @@ struct file_operations ll_file_operations_noflock = {
 	.release	= ll_file_release,
 	.mmap	   = ll_file_mmap,
 	.llseek	 = ll_file_seek,
-	.splice_read    = ll_file_splice_read,
+	.splice_read    = generic_file_splice_read,
 	.fsync	  = ll_fsync,
 	.flush	  = ll_flush,
 	.flock	  = ll_file_noflock,

drivers/staging/lustre/lustre/llite/llite_internal.h

@@ -908,17 +908,11 @@ void vvp_write_complete(struct vvp_object *club, struct vvp_page *page);
  */
 struct vvp_io_args {
 	/** normal/splice */
-	enum vvp_io_subtype via_io_subtype;
-
 	union {
 		struct {
 			struct kiocb      *via_iocb;
 			struct iov_iter   *via_iter;
 		} normal;
-		struct {
-			struct pipe_inode_info  *via_pipe;
-			unsigned int       via_flags;
-		} splice;
 	} u;
 };
 
@@ -946,14 +940,9 @@ static inline struct ll_thread_info *ll_env_info(const struct lu_env *env)
 	return lti;
 }
 
-static inline struct vvp_io_args *ll_env_args(const struct lu_env *env,
+static inline struct vvp_io_args *ll_env_args(const struct lu_env *env)
-					      enum vvp_io_subtype type)
 {
-	struct vvp_io_args *via = &ll_env_info(env)->lti_args;
+	return &ll_env_info(env)->lti_args;
-
-	via->via_io_subtype = type;
-
-	return via;
 }
 
 void ll_queue_done_writing(struct inode *inode, unsigned long flags);

drivers/staging/lustre/lustre/llite/vvp_internal.h

@@ -49,14 +49,6 @@ struct obd_device;
 struct obd_export;
 struct page;
 
-/* specific architecture can implement only part of this list */
-enum vvp_io_subtype {
-	/** normal IO */
-	IO_NORMAL,
-	/** io started from splice_{read|write} */
-	IO_SPLICE
-};
-
 /**
  * IO state private to IO state private to VVP layer.
  */
@@ -98,10 +90,6 @@ struct vvp_io {
 			 */
 			bool		ft_flags_valid;
 		} fault;
-		struct {
-			struct pipe_inode_info	*vui_pipe;
-			unsigned int		 vui_flags;
-		} splice;
 		struct {
 			struct cl_page_list vui_queue;
 			unsigned long vui_written;
@@ -110,8 +98,6 @@ struct vvp_io {
 		} write;
 	} u;
 
-	enum vvp_io_subtype	vui_io_subtype;
-
 	/**
 	 * Layout version when this IO is initialized
 	 */

drivers/staging/lustre/lustre/llite/vvp_io.c

@@ -53,18 +53,6 @@ static struct vvp_io *cl2vvp_io(const struct lu_env *env,
 	return vio;
 }
 
-/**
- * True, if \a io is a normal io, False for splice_{read,write}
- */
-static int cl_is_normalio(const struct lu_env *env, const struct cl_io *io)
-{
-	struct vvp_io *vio = vvp_env_io(env);
-
-	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
-
-	return vio->vui_io_subtype == IO_NORMAL;
-}
-
 /**
  * For swapping layout. The file's layout may have changed.
  * To avoid populating pages to a wrong stripe, we have to verify the
@@ -390,9 +378,6 @@ static int vvp_mmap_locks(const struct lu_env *env,
 
 	LASSERT(io->ci_type == CIT_READ || io->ci_type == CIT_WRITE);
 
-	if (!cl_is_normalio(env, io))
-		return 0;
-
 	if (!vio->vui_iter) /* nfs or loop back device write */
 		return 0;
 
@@ -461,15 +446,10 @@ static void vvp_io_advance(const struct lu_env *env,
 			   const struct cl_io_slice *ios,
 			   size_t nob)
 {
-	struct vvp_io    *vio = cl2vvp_io(env, ios);
-	struct cl_io     *io  = ios->cis_io;
 	struct cl_object *obj = ios->cis_io->ci_obj;
-
+	struct vvp_io	 *vio = cl2vvp_io(env, ios);
 	CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 
-	if (!cl_is_normalio(env, io))
-		return;
-
 	iov_iter_reexpand(vio->vui_iter, vio->vui_tot_count  -= nob);
 }
 
@@ -478,7 +458,7 @@ static void vvp_io_update_iov(const struct lu_env *env,
 {
 	size_t size = io->u.ci_rw.crw_count;
 
-	if (!cl_is_normalio(env, io) || !vio->vui_iter)
+	if (!vio->vui_iter)
 		return;
 
 	iov_iter_truncate(vio->vui_iter, size);
@@ -715,25 +695,8 @@ static int vvp_io_read_start(const struct lu_env *env,
 
 	/* BUG: 5972 */
 	file_accessed(file);
-	switch (vio->vui_io_subtype) {
-	case IO_NORMAL:
 	LASSERT(vio->vui_iocb->ki_pos == pos);
 	result = generic_file_read_iter(vio->vui_iocb, vio->vui_iter);
-		break;
-	case IO_SPLICE:
-		result = generic_file_splice_read(file, &pos,
-						  vio->u.splice.vui_pipe, cnt,
-						  vio->u.splice.vui_flags);
-		/* LU-1109: do splice read stripe by stripe otherwise if it
-		 * may make nfsd stuck if this read occupied all internal pipe
-		 * buffers.
-		 */
-		io->ci_continue = 0;
-		break;
-	default:
-		CERROR("Wrong IO type %u\n", vio->vui_io_subtype);
-		LBUG();
-	}
 
 out:
 	if (result >= 0) {

fs/coda/file.c

@@ -37,27 +37,6 @@ coda_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return vfs_iter_read(cfi->cfi_container, to, &iocb->ki_pos);
 }
 
-static ssize_t
-coda_file_splice_read(struct file *coda_file, loff_t *ppos,
-		      struct pipe_inode_info *pipe, size_t count,
-		      unsigned int flags)
-{
-	ssize_t (*splice_read)(struct file *, loff_t *,
-			       struct pipe_inode_info *, size_t, unsigned int);
-	struct coda_file_info *cfi;
-	struct file *host_file;
-
-	cfi = CODA_FTOC(coda_file);
-	BUG_ON(!cfi || cfi->cfi_magic != CODA_MAGIC);
-	host_file = cfi->cfi_container;
-
-	splice_read = host_file->f_op->splice_read;
-	if (!splice_read)
-		splice_read = default_file_splice_read;
-
-	return splice_read(host_file, ppos, pipe, count, flags);
-}
-
 static ssize_t
 coda_file_write_iter(struct kiocb *iocb, struct iov_iter *to)
 {
@@ -225,6 +204,6 @@ const struct file_operations coda_file_operations = {
 	.open		= coda_open,
 	.release	= coda_release,
 	.fsync		= coda_fsync,
-	.splice_read	= coda_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 };
 

fs/direct-io.c

@@ -246,6 +246,9 @@ static ssize_t dio_complete(struct dio *dio, ssize_t ret, bool is_async)
 		if ((dio->op == REQ_OP_READ) &&
 		    ((offset + transferred) > dio->i_size))
 			transferred = dio->i_size - offset;
+		/* ignore EFAULT if some IO has been done */
+		if (unlikely(ret == -EFAULT) && transferred)
+			ret = 0;
 	}
 
 	if (ret == 0)

fs/fuse/dev.c

@@ -728,7 +728,7 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
 		struct pipe_buffer *buf = cs->pipebufs;
 
 		if (!cs->write) {
-			err = buf->ops->confirm(cs->pipe, buf);
+			err = pipe_buf_confirm(cs->pipe, buf);
 			if (err)
 				return err;
 
@@ -827,7 +827,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 
 	fuse_copy_finish(cs);
 
-	err = buf->ops->confirm(cs->pipe, buf);
+	err = pipe_buf_confirm(cs->pipe, buf);
 	if (err)
 		return err;
 
@@ -840,7 +840,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
 	if (cs->len != PAGE_SIZE)
 		goto out_fallback;
 
-	if (buf->ops->steal(cs->pipe, buf) != 0)
+	if (pipe_buf_steal(cs->pipe, buf) != 0)
 		goto out_fallback;
 
 	newpage = buf->page;
@@ -1341,9 +1341,8 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 				    struct pipe_inode_info *pipe,
 				    size_t len, unsigned int flags)
 {
-	int ret;
+	int total, ret;
 	int page_nr = 0;
-	int do_wakeup = 0;
 	struct pipe_buffer *bufs;
 	struct fuse_copy_state cs;
 	struct fuse_dev *fud = fuse_get_dev(in);
@@ -1362,52 +1361,23 @@ static ssize_t fuse_dev_splice_read(struct file *in, loff_t *ppos,
 	if (ret < 0)
 		goto out;
 
-	ret = 0;
-	pipe_lock(pipe);
-
-	if (!pipe->readers) {
-		send_sig(SIGPIPE, current, 0);
-		if (!ret)
-			ret = -EPIPE;
-		goto out_unlock;
-	}
-
 	if (pipe->nrbufs + cs.nr_segs > pipe->buffers) {
 		ret = -EIO;
-		goto out_unlock;
+		goto out;
 	}
 
-	while (page_nr < cs.nr_segs) {
+	for (ret = total = 0; page_nr < cs.nr_segs; total += ret) {
-		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
-		struct pipe_buffer *buf = pipe->bufs + newbuf;
-
-		buf->page = bufs[page_nr].page;
-		buf->offset = bufs[page_nr].offset;
-		buf->len = bufs[page_nr].len;
 		/*
 		 * Need to be careful about this.  Having buf->ops in module
 		 * code can Oops if the buffer persists after module unload.
 		 */
-		buf->ops = &nosteal_pipe_buf_ops;
+		bufs[page_nr].ops = &nosteal_pipe_buf_ops;
-
+		ret = add_to_pipe(pipe, &bufs[page_nr++]);
-		pipe->nrbufs++;
+		if (unlikely(ret < 0))
-		page_nr++;
+			break;
-		ret += buf->len;
-
-		if (pipe->files)
-			do_wakeup = 1;
 	}
-
+	if (total)
-out_unlock:
+		ret = total;
-	pipe_unlock(pipe);
-
-	if (do_wakeup) {
-		smp_mb();
-		if (waitqueue_active(&pipe->wait))
-			wake_up_interruptible(&pipe->wait);
-		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
-	}
-
 out:
 	for (; page_nr < cs.nr_segs; page_nr++)
 		put_page(bufs[page_nr].page);
@@ -1992,7 +1962,7 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 			pipe->nrbufs--;
 		} else {
-			ibuf->ops->get(pipe, ibuf);
+			pipe_buf_get(pipe, ibuf);
 			*obuf = *ibuf;
 			obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
 			obuf->len = rem;
@@ -2014,10 +1984,9 @@ static ssize_t fuse_dev_splice_write(struct pipe_inode_info *pipe,
 
 	ret = fuse_dev_do_write(fud, &cs, len);
 
-	for (idx = 0; idx < nbuf; idx++) {
+	for (idx = 0; idx < nbuf; idx++)
-		struct pipe_buffer *buf = &bufs[idx];
+		pipe_buf_release(pipe, &bufs[idx]);
-		buf->ops->release(pipe, buf);
+
-	}
 out:
 	kfree(bufs);
 	return ret;

fs/gfs2/file.c

@@ -954,30 +954,6 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset, loff_t le
 	return ret;
 }
 
-static ssize_t gfs2_file_splice_read(struct file *in, loff_t *ppos,
-				     struct pipe_inode_info *pipe, size_t len,
-				     unsigned int flags)
-{
-	struct inode *inode = in->f_mapping->host;
-	struct gfs2_inode *ip = GFS2_I(inode);
-	struct gfs2_holder gh;
-	int ret;
-
-	inode_lock(inode);
-
-	ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
-	if (ret) {
-		inode_unlock(inode);
-		return ret;
-	}
-
-	gfs2_glock_dq_uninit(&gh);
-	inode_unlock(inode);
-
-	return generic_file_splice_read(in, ppos, pipe, len, flags);
-}
-
-
 static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
 				      struct file *out, loff_t *ppos,
 				      size_t len, unsigned int flags)
@@ -1140,7 +1116,7 @@ const struct file_operations gfs2_file_fops = {
 	.fsync		= gfs2_fsync,
 	.lock		= gfs2_lock,
 	.flock		= gfs2_flock,
-	.splice_read	= gfs2_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= gfs2_file_splice_write,
 	.setlease	= simple_nosetlease,
 	.fallocate	= gfs2_fallocate,
@@ -1168,7 +1144,7 @@ const struct file_operations gfs2_file_fops_nolock = {
 	.open		= gfs2_open,
 	.release	= gfs2_release,
 	.fsync		= gfs2_fsync,
-	.splice_read	= gfs2_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= gfs2_file_splice_write,
 	.setlease	= generic_setlease,
 	.fallocate	= gfs2_fallocate,

fs/nfs/file.c

@@ -182,29 +182,6 @@ nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
 }
 EXPORT_SYMBOL_GPL(nfs_file_read);
 
-ssize_t
-nfs_file_splice_read(struct file *filp, loff_t *ppos,
-		     struct pipe_inode_info *pipe, size_t count,
-		     unsigned int flags)
-{
-	struct inode *inode = file_inode(filp);
-	ssize_t res;
-
-	dprintk("NFS: splice_read(%pD2, %lu@%Lu)\n",
-		filp, (unsigned long) count, (unsigned long long) *ppos);
-
-	nfs_start_io_read(inode);
-	res = nfs_revalidate_mapping(inode, filp->f_mapping);
-	if (!res) {
-		res = generic_file_splice_read(filp, ppos, pipe, count, flags);
-		if (res > 0)
-			nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
-	}
-	nfs_end_io_read(inode);
-	return res;
-}
-EXPORT_SYMBOL_GPL(nfs_file_splice_read);
-
 int
 nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
 {
@@ -871,7 +848,7 @@ const struct file_operations nfs_file_operations = {
 	.fsync		= nfs_file_fsync,
 	.lock		= nfs_lock,
 	.flock		= nfs_flock,
-	.splice_read	= nfs_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.check_flags	= nfs_check_flags,
 	.setlease	= simple_nosetlease,

fs/nfs/internal.h

@@ -365,8 +365,6 @@ int nfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *)
 int nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync);
 loff_t nfs_file_llseek(struct file *, loff_t, int);
 ssize_t nfs_file_read(struct kiocb *, struct iov_iter *);
-ssize_t nfs_file_splice_read(struct file *, loff_t *, struct pipe_inode_info *,
-			     size_t, unsigned int);
 int nfs_file_mmap(struct file *, struct vm_area_struct *);
 ssize_t nfs_file_write(struct kiocb *, struct iov_iter *);
 int nfs_file_release(struct inode *, struct file *);

fs/nfs/nfs4file.c

@@ -248,7 +248,7 @@ const struct file_operations nfs4_file_operations = {
 	.fsync		= nfs_file_fsync,
 	.lock		= nfs_lock,
 	.flock		= nfs_flock,
-	.splice_read	= nfs_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.check_flags	= nfs_check_flags,
 	.setlease	= simple_nosetlease,

fs/ocfs2/file.c

@@ -2321,36 +2321,6 @@ static ssize_t ocfs2_file_write_iter(struct kiocb *iocb,
 	return ret;
 }
 
-static ssize_t ocfs2_file_splice_read(struct file *in,
-				      loff_t *ppos,
-				      struct pipe_inode_info *pipe,
-				      size_t len,
-				      unsigned int flags)
-{
-	int ret = 0, lock_level = 0;
-	struct inode *inode = file_inode(in);
-
-	trace_ocfs2_file_splice_read(inode, in, in->f_path.dentry,
-			(unsigned long long)OCFS2_I(inode)->ip_blkno,
-			in->f_path.dentry->d_name.len,
-			in->f_path.dentry->d_name.name, len);
-
-	/*
-	 * See the comment in ocfs2_file_read_iter()
-	 */
-	ret = ocfs2_inode_lock_atime(inode, in->f_path.mnt, &lock_level);
-	if (ret < 0) {
-		mlog_errno(ret);
-		goto bail;
-	}
-	ocfs2_inode_unlock(inode, lock_level);
-
-	ret = generic_file_splice_read(in, ppos, pipe, len, flags);
-
-bail:
-	return ret;
-}
-
 static ssize_t ocfs2_file_read_iter(struct kiocb *iocb,
 				   struct iov_iter *to)
 {
@@ -2509,7 +2479,7 @@ const struct file_operations ocfs2_fops = {
 #endif
 	.lock		= ocfs2_lock,
 	.flock		= ocfs2_flock,
-	.splice_read	= ocfs2_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ocfs2_fallocate,
 };
@@ -2554,7 +2524,7 @@ const struct file_operations ocfs2_fops_no_plocks = {
 	.compat_ioctl   = ocfs2_compat_ioctl,
 #endif
 	.flock		= ocfs2_flock,
-	.splice_read	= ocfs2_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= ocfs2_fallocate,
 };

fs/ocfs2/ocfs2_trace.h

@@ -1314,8 +1314,6 @@ DEFINE_OCFS2_FILE_OPS(ocfs2_file_aio_write);
 
 DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_write);
 
-DEFINE_OCFS2_FILE_OPS(ocfs2_file_splice_read);
-
 DEFINE_OCFS2_FILE_OPS(ocfs2_file_aio_read);
 
 DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_truncate_file);

fs/pipe.c

@@ -267,7 +267,6 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 		if (bufs) {
 			int curbuf = pipe->curbuf;
 			struct pipe_buffer *buf = pipe->bufs + curbuf;
-			const struct pipe_buf_operations *ops = buf->ops;
 			size_t chars = buf->len;
 			size_t written;
 			int error;
@@ -275,7 +274,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 			if (chars > total_len)
 				chars = total_len;
 
-			error = ops->confirm(pipe, buf);
+			error = pipe_buf_confirm(pipe, buf);
 			if (error) {
 				if (!ret)
 					ret = error;
@@ -299,8 +298,7 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to)
 			}
 
 			if (!buf->len) {
-				buf->ops = NULL;
+				pipe_buf_release(pipe, buf);
-				ops->release(pipe, buf);
 				curbuf = (curbuf + 1) & (pipe->buffers - 1);
 				pipe->curbuf = curbuf;
 				pipe->nrbufs = --bufs;
@@ -383,11 +381,10 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
 							(pipe->buffers - 1);
 		struct pipe_buffer *buf = pipe->bufs + lastbuf;
-		const struct pipe_buf_operations *ops = buf->ops;
 		int offset = buf->offset + buf->len;
 
-		if (ops->can_merge && offset + chars <= PAGE_SIZE) {
+		if (buf->ops->can_merge && offset + chars <= PAGE_SIZE) {
-			ret = ops->confirm(pipe, buf);
+			ret = pipe_buf_confirm(pipe, buf);
 			if (ret)
 				goto out;
 
@@ -664,7 +661,7 @@ void free_pipe_info(struct pipe_inode_info *pipe)
 	for (i = 0; i < pipe->buffers; i++) {
 		struct pipe_buffer *buf = pipe->bufs + i;
 		if (buf->ops)
-			buf->ops->release(pipe, buf);
+			pipe_buf_release(pipe, buf);
 	}
 	if (pipe->tmp_page)
 		__free_page(pipe->tmp_page);

fs/splice.c

@@ -183,26 +183,18 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 		       struct splice_pipe_desc *spd)
 {
 	unsigned int spd_pages = spd->nr_pages;
-	int ret, do_wakeup, page_nr;
+	int ret = 0, page_nr = 0;
 
 	if (!spd_pages)
 		return 0;
 
-	ret = 0;
+	if (unlikely(!pipe->readers)) {
-	do_wakeup = 0;
-	page_nr = 0;
-
-	pipe_lock(pipe);
-
-	for (;;) {
-		if (!pipe->readers) {
 		send_sig(SIGPIPE, current, 0);
-			if (!ret)
 		ret = -EPIPE;
-			break;
+		goto out;
 	}
 
-		if (pipe->nrbufs < pipe->buffers) {
+	while (pipe->nrbufs < pipe->buffers) {
 		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
 		struct pipe_buffer *buf = pipe->bufs + newbuf;
 
@@ -211,54 +203,19 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 		buf->len = spd->partial[page_nr].len;
 		buf->private = spd->partial[page_nr].private;
 		buf->ops = spd->ops;
-			if (spd->flags & SPLICE_F_GIFT)
-				buf->flags |= PIPE_BUF_FLAG_GIFT;
 
 		pipe->nrbufs++;
 		page_nr++;
 		ret += buf->len;
 
-			if (pipe->files)
-				do_wakeup = 1;
-
 		if (!--spd->nr_pages)
-				break;
-			if (pipe->nrbufs < pipe->buffers)
-				continue;
-
 			break;
 	}
 
-		if (spd->flags & SPLICE_F_NONBLOCK) {
 	if (!ret)
 		ret = -EAGAIN;
-			break;
-		}
-
-		if (signal_pending(current)) {
-			if (!ret)
-				ret = -ERESTARTSYS;
-			break;
-		}
-
-		if (do_wakeup) {
-			smp_mb();
-			if (waitqueue_active(&pipe->wait))
-				wake_up_interruptible_sync(&pipe->wait);
-			kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
-			do_wakeup = 0;
-		}
-
-		pipe->waiting_writers++;
-		pipe_wait(pipe);
-		pipe->waiting_writers--;
-	}
-
-	pipe_unlock(pipe);
-
-	if (do_wakeup)
-		wakeup_pipe_readers(pipe);
 
+out:
 	while (page_nr < spd_pages)
 		spd->spd_release(spd, page_nr++);
 
@@ -266,6 +223,26 @@ ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
 }
 EXPORT_SYMBOL_GPL(splice_to_pipe);
 
+ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
+{
+	int ret;
+
+	if (unlikely(!pipe->readers)) {
+		send_sig(SIGPIPE, current, 0);
+		ret = -EPIPE;
+	} else if (pipe->nrbufs == pipe->buffers) {
+		ret = -EAGAIN;
+	} else {
+		int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+		pipe->bufs[newbuf] = *buf;
+		pipe->nrbufs++;
+		return buf->len;
+	}
+	pipe_buf_release(pipe, buf);
+	return ret;
+}
+EXPORT_SYMBOL(add_to_pipe);
+
 void spd_release_page(struct splice_pipe_desc *spd, unsigned int i)
 {
 	put_page(spd->pages[i]);
@@ -303,207 +280,6 @@ void splice_shrink_spd(struct splice_pipe_desc *spd)
 	kfree(spd->partial);
 }
 
-static int
-__generic_file_splice_read(struct file *in, loff_t *ppos,
-			   struct pipe_inode_info *pipe, size_t len,
-			   unsigned int flags)
-{
-	struct address_space *mapping = in->f_mapping;
-	unsigned int loff, nr_pages, req_pages;
-	struct page *pages[PIPE_DEF_BUFFERS];
-	struct partial_page partial[PIPE_DEF_BUFFERS];
-	struct page *page;
-	pgoff_t index, end_index;
-	loff_t isize;
-	int error, page_nr;
-	struct splice_pipe_desc spd = {
-		.pages = pages,
-		.partial = partial,
-		.nr_pages_max = PIPE_DEF_BUFFERS,
-		.flags = flags,
-		.ops = &page_cache_pipe_buf_ops,
-		.spd_release = spd_release_page,
-	};
-
-	if (splice_grow_spd(pipe, &spd))
-		return -ENOMEM;
-
-	index = *ppos >> PAGE_SHIFT;
-	loff = *ppos & ~PAGE_MASK;
-	req_pages = (len + loff + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	nr_pages = min(req_pages, spd.nr_pages_max);
-
-	/*
-	 * Lookup the (hopefully) full range of pages we need.
-	 */
-	spd.nr_pages = find_get_pages_contig(mapping, index, nr_pages, spd.pages);
-	index += spd.nr_pages;
-
-	/*
-	 * If find_get_pages_contig() returned fewer pages than we needed,
-	 * readahead/allocate the rest and fill in the holes.
-	 */
-	if (spd.nr_pages < nr_pages)
-		page_cache_sync_readahead(mapping, &in->f_ra, in,
-				index, req_pages - spd.nr_pages);
-
-	error = 0;
-	while (spd.nr_pages < nr_pages) {
-		/*
-		 * Page could be there, find_get_pages_contig() breaks on
-		 * the first hole.
-		 */
-		page = find_get_page(mapping, index);
-		if (!page) {
-			/*
-			 * page didn't exist, allocate one.
-			 */
-			page = page_cache_alloc_cold(mapping);
-			if (!page)
-				break;
-
-			error = add_to_page_cache_lru(page, mapping, index,
-				   mapping_gfp_constraint(mapping, GFP_KERNEL));
-			if (unlikely(error)) {
-				put_page(page);
-				if (error == -EEXIST)
-					continue;
-				break;
-			}
-			/*
-			 * add_to_page_cache() locks the page, unlock it
-			 * to avoid convoluting the logic below even more.
-			 */
-			unlock_page(page);
-		}
-
-		spd.pages[spd.nr_pages++] = page;
-		index++;
-	}
-
-	/*
-	 * Now loop over the map and see if we need to start IO on any
-	 * pages, fill in the partial map, etc.
-	 */
-	index = *ppos >> PAGE_SHIFT;
-	nr_pages = spd.nr_pages;
-	spd.nr_pages = 0;
-	for (page_nr = 0; page_nr < nr_pages; page_nr++) {
-		unsigned int this_len;
-
-		if (!len)
-			break;
-
-		/*
-		 * this_len is the max we'll use from this page
-		 */
-		this_len = min_t(unsigned long, len, PAGE_SIZE - loff);
-		page = spd.pages[page_nr];
-
-		if (PageReadahead(page))
-			page_cache_async_readahead(mapping, &in->f_ra, in,
-					page, index, req_pages - page_nr);
-
-		/*
-		 * If the page isn't uptodate, we may need to start io on it
-		 */
-		if (!PageUptodate(page)) {
-			lock_page(page);
-
-			/*
-			 * Page was truncated, or invalidated by the
-			 * filesystem.  Redo the find/create, but this time the
-			 * page is kept locked, so there's no chance of another
-			 * race with truncate/invalidate.
-			 */
-			if (!page->mapping) {
-				unlock_page(page);
-retry_lookup:
-				page = find_or_create_page(mapping, index,
-						mapping_gfp_mask(mapping));
-
-				if (!page) {
-					error = -ENOMEM;
-					break;
-				}
-				put_page(spd.pages[page_nr]);
-				spd.pages[page_nr] = page;
-			}
-			/*
-			 * page was already under io and is now done, great
-			 */
-			if (PageUptodate(page)) {
-				unlock_page(page);
-				goto fill_it;
-			}
-
-			/*
-			 * need to read in the page
-			 */
-			error = mapping->a_ops->readpage(in, page);
-			if (unlikely(error)) {
-				/*
-				 * Re-lookup the page
-				 */
-				if (error == AOP_TRUNCATED_PAGE)
-					goto retry_lookup;
-
-				break;
-			}
-		}
-fill_it:
-		/*
-		 * i_size must be checked after PageUptodate.
-		 */
-		isize = i_size_read(mapping->host);
-		end_index = (isize - 1) >> PAGE_SHIFT;
-		if (unlikely(!isize || index > end_index))
-			break;
-
-		/*
-		 * if this is the last page, see if we need to shrink
-		 * the length and stop
-		 */
-		if (end_index == index) {
-			unsigned int plen;
-
-			/*
-			 * max good bytes in this page
-			 */
-			plen = ((isize - 1) & ~PAGE_MASK) + 1;
-			if (plen <= loff)
-				break;
-
-			/*
-			 * force quit after adding this page
-			 */
-			this_len = min(this_len, plen - loff);
-			len = this_len;
-		}
-
-		spd.partial[page_nr].offset = loff;
-		spd.partial[page_nr].len = this_len;
-		len -= this_len;
-		loff = 0;
-		spd.nr_pages++;
-		index++;
-	}
-
-	/*
-	 * Release any pages at the end, if we quit early. 'page_nr' is how far
-	 * we got, 'nr_pages' is how many pages are in the map.
-	 */
-	while (page_nr < nr_pages)
-		put_page(spd.pages[page_nr++]);
-	in->f_ra.prev_pos = (loff_t)index << PAGE_SHIFT;
-
-	if (spd.nr_pages)
-		error = splice_to_pipe(pipe, &spd);
-
-	splice_shrink_spd(&spd);
-	return error;
-}
-
 /**
  * generic_file_splice_read - splice data from file to a pipe
  * @in:		file to splice from
@@ -514,39 +290,53 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
  *
  * Description:
  *    Will read pages from given file and fill them into a pipe. Can be
- *    used as long as the address_space operations for the source implements
+ *    used as long as it has more or less sane ->read_iter().
- *    a readpage() hook.
  *
  */
 ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
 				 struct pipe_inode_info *pipe, size_t len,
 				 unsigned int flags)
 {
-	loff_t isize, left;
+	struct iov_iter to;
-	int ret;
+	struct kiocb kiocb;
-
+	loff_t isize;
-	if (IS_DAX(in->f_mapping->host))
+	int idx, ret;
-		return default_file_splice_read(in, ppos, pipe, len, flags);
 
 	isize = i_size_read(in->f_mapping->host);
 	if (unlikely(*ppos >= isize))
 		return 0;
 
-	left = isize - *ppos;
+	iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len);
-	if (unlikely(left < len))
+	idx = to.idx;
-		len = left;
+	init_sync_kiocb(&kiocb, in);
-
+	kiocb.ki_pos = *ppos;
-	ret = __generic_file_splice_read(in, ppos, pipe, len, flags);
+	ret = in->f_op->read_iter(&kiocb, &to);
 	if (ret > 0) {
-		*ppos += ret;
+		*ppos = kiocb.ki_pos;
 		file_accessed(in);
+	} else if (ret < 0) {
+		if (WARN_ON(to.idx != idx || to.iov_offset)) {
+			/*
+			 * a bogus ->read_iter() has copied something and still
+			 * returned an error instead of a short read.
+			 */
+			to.idx = idx;
+			to.iov_offset = 0;
+			iov_iter_advance(&to, 0); /* to free what was emitted */
+		}
+		/*
+		 * callers of ->splice_read() expect -EAGAIN on
+		 * "can't put anything in there", rather than -EFAULT.
+		 */
+		if (ret == -EFAULT)
+			ret = -EAGAIN;
 	}
 
 	return ret;
 }
 EXPORT_SYMBOL(generic_file_splice_read);
 
-static const struct pipe_buf_operations default_pipe_buf_ops = {
+const struct pipe_buf_operations default_pipe_buf_ops = {
 	.can_merge = 0,
 	.confirm = generic_pipe_buf_confirm,
 	.release = generic_pipe_buf_release,
@@ -570,7 +360,7 @@ const struct pipe_buf_operations nosteal_pipe_buf_ops = {
 };
 EXPORT_SYMBOL(nosteal_pipe_buf_ops);
 
-static ssize_t kernel_readv(struct file *file, const struct iovec *vec,
+static ssize_t kernel_readv(struct file *file, const struct kvec *vec,
 			    unsigned long vlen, loff_t offset)
 {
 	mm_segment_t old_fs;
@@ -602,102 +392,70 @@ ssize_t kernel_write(struct file *file, const char *buf, size_t count,
 }
 EXPORT_SYMBOL(kernel_write);
 
-ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
+static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
 				 struct pipe_inode_info *pipe, size_t len,
 				 unsigned int flags)
 {
+	struct kvec *vec, __vec[PIPE_DEF_BUFFERS];
+	struct iov_iter to;
+	struct page **pages;
 	unsigned int nr_pages;
-	unsigned int nr_freed;
+	size_t offset, dummy, copied = 0;
-	size_t offset;
-	struct page *pages[PIPE_DEF_BUFFERS];
-	struct partial_page partial[PIPE_DEF_BUFFERS];
-	struct iovec *vec, __vec[PIPE_DEF_BUFFERS];
 	ssize_t res;
-	size_t this_len;
-	int error;
 	int i;
-	struct splice_pipe_desc spd = {
-		.pages = pages,
-		.partial = partial,
-		.nr_pages_max = PIPE_DEF_BUFFERS,
-		.flags = flags,
-		.ops = &default_pipe_buf_ops,
-		.spd_release = spd_release_page,
-	};
 
-	if (splice_grow_spd(pipe, &spd))
+	if (pipe->nrbufs == pipe->buffers)
+		return -EAGAIN;
+
+	/*
+	 * Try to keep page boundaries matching to source pagecache ones -
+	 * it probably won't be much help, but...
+	 */
+	offset = *ppos & ~PAGE_MASK;
+
+	iov_iter_pipe(&to, ITER_PIPE | READ, pipe, len + offset);
+
+	res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &dummy);
+	if (res <= 0)
 		return -ENOMEM;
 
-	res = -ENOMEM;
+	nr_pages = res / PAGE_SIZE;
+
 	vec = __vec;
-	if (spd.nr_pages_max > PIPE_DEF_BUFFERS) {
+	if (nr_pages > PIPE_DEF_BUFFERS) {
-		vec = kmalloc(spd.nr_pages_max * sizeof(struct iovec), GFP_KERNEL);
+		vec = kmalloc(nr_pages * sizeof(struct kvec), GFP_KERNEL);
-		if (!vec)
+		if (unlikely(!vec)) {
-			goto shrink_ret;
+			res = -ENOMEM;
+			goto out;
+		}
 	}
 
-	offset = *ppos & ~PAGE_MASK;
+	pipe->bufs[to.idx].offset = offset;
-	nr_pages = (len + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	pipe->bufs[to.idx].len -= offset;
 
-	for (i = 0; i < nr_pages && i < spd.nr_pages_max && len; i++) {
+	for (i = 0; i < nr_pages; i++) {
-		struct page *page;
+		size_t this_len = min_t(size_t, len, PAGE_SIZE - offset);
-
+		vec[i].iov_base = page_address(pages[i]) + offset;
-		page = alloc_page(GFP_USER);
-		error = -ENOMEM;
-		if (!page)
-			goto err;
-
-		this_len = min_t(size_t, len, PAGE_SIZE - offset);
-		vec[i].iov_base = (void __user *) page_address(page);
 		vec[i].iov_len = this_len;
-		spd.pages[i] = page;
-		spd.nr_pages++;
 		len -= this_len;
 		offset = 0;
 	}
 
-	res = kernel_readv(in, vec, spd.nr_pages, *ppos);
+	res = kernel_readv(in, vec, nr_pages, *ppos);
-	if (res < 0) {
+	if (res > 0) {
-		error = res;
+		copied = res;
-		goto err;
-	}
-
-	error = 0;
-	if (!res)
-		goto err;
-
-	nr_freed = 0;
-	for (i = 0; i < spd.nr_pages; i++) {
-		this_len = min_t(size_t, vec[i].iov_len, res);
-		spd.partial[i].offset = 0;
-		spd.partial[i].len = this_len;
-		if (!this_len) {
-			__free_page(spd.pages[i]);
-			spd.pages[i] = NULL;
-			nr_freed++;
-		}
-		res -= this_len;
-	}
-	spd.nr_pages -= nr_freed;
-
-	res = splice_to_pipe(pipe, &spd);
-	if (res > 0)
 		*ppos += res;
+	}
 
-shrink_ret:
 	if (vec != __vec)
 		kfree(vec);
-	splice_shrink_spd(&spd);
+out:
+	for (i = 0; i < nr_pages; i++)
+		put_page(pages[i]);
+	kvfree(pages);
+	iov_iter_advance(&to, copied);	/* truncates and discards */
 	return res;
-
-err:
-	for (i = 0; i < spd.nr_pages; i++)
-		__free_page(spd.pages[i]);
-
-	res = error;
-	goto shrink_ret;
 }
-EXPORT_SYMBOL(default_file_splice_read);
 
 /*
  * Send 'sd->len' bytes to socket from 'sd->file' at position 'sd->pos'
@@ -757,13 +515,12 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
 
 	while (pipe->nrbufs) {
 		struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
-		const struct pipe_buf_operations *ops = buf->ops;
 
 		sd->len = buf->len;
 		if (sd->len > sd->total_len)
 			sd->len = sd->total_len;
 
-		ret = buf->ops->confirm(pipe, buf);
+		ret = pipe_buf_confirm(pipe, buf);
 		if (unlikely(ret)) {
 			if (ret == -ENODATA)
 				ret = 0;
@@ -783,8 +540,7 @@ static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_des
 		sd->total_len -= ret;
 
 		if (!buf->len) {
-			buf->ops = NULL;
+			pipe_buf_release(pipe, buf);
-			ops->release(pipe, buf);
 			pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 			pipe->nrbufs--;
 			if (pipe->files)
@@ -1003,7 +759,7 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 			if (idx == pipe->buffers - 1)
 				idx = -1;
 
-			ret = buf->ops->confirm(pipe, buf);
+			ret = pipe_buf_confirm(pipe, buf);
 			if (unlikely(ret)) {
 				if (ret == -ENODATA)
 					ret = 0;
@@ -1030,11 +786,9 @@ iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
 		while (ret) {
 			struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
 			if (ret >= buf->len) {
-				const struct pipe_buf_operations *ops = buf->ops;
 				ret -= buf->len;
 				buf->len = 0;
-				buf->ops = NULL;
+				pipe_buf_release(pipe, buf);
-				ops->release(pipe, buf);
 				pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
 				pipe->nrbufs--;
 				if (pipe->files)
@@ -1273,10 +1027,8 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
 	for (i = 0; i < pipe->buffers; i++) {
 		struct pipe_buffer *buf = pipe->bufs + i;
 
-		if (buf->ops) {
+		if (buf->ops)
-			buf->ops->release(pipe, buf);
+			pipe_buf_release(pipe, buf);
-			buf->ops = NULL;
-		}
 	}
 
 	if (!bytes)
@@ -1342,6 +1094,20 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
 }
 EXPORT_SYMBOL(do_splice_direct);
 
+static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
+{
+	while (pipe->nrbufs == pipe->buffers) {
+		if (flags & SPLICE_F_NONBLOCK)
+			return -EAGAIN;
+		if (signal_pending(current))
+			return -ERESTARTSYS;
+		pipe->waiting_writers++;
+		pipe_wait(pipe);
+		pipe->waiting_writers--;
+	}
+	return 0;
+}
+
 static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
 			       struct pipe_inode_info *opipe,
 			       size_t len, unsigned int flags);
@@ -1424,8 +1190,13 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 			offset = in->f_pos;
 		}
 
+		pipe_lock(opipe);
+		ret = wait_for_space(opipe, flags);
+		if (!ret)
 			ret = do_splice_to(in, &offset, opipe, len, flags);
-
+		pipe_unlock(opipe);
+		if (ret > 0)
+			wakeup_pipe_readers(opipe);
 		if (!off_in)
 			in->f_pos = offset;
 		else if (copy_to_user(off_in, &offset, sizeof(loff_t)))
@@ -1437,106 +1208,50 @@ static long do_splice(struct file *in, loff_t __user *off_in,
 	return -EINVAL;
 }
 
-/*
+static int iter_to_pipe(struct iov_iter *from,
- * Map an iov into an array of pages and offset/length tupples. With the
+			struct pipe_inode_info *pipe,
- * partial_page structure, we can map several non-contiguous ranges into
+			unsigned flags)
- * our ones pages[] map instead of splitting that operation into pieces.
- * Could easily be exported as a generic helper for other users, in which
- * case one would probably want to add a 'max_nr_pages' parameter as well.
- */
-static int get_iovec_page_array(const struct iovec __user *iov,
-				unsigned int nr_vecs, struct page **pages,
-				struct partial_page *partial, bool aligned,
-				unsigned int pipe_buffers)
 {
-	int buffers = 0, error = 0;
+	struct pipe_buffer buf = {
+		.ops = &user_page_pipe_buf_ops,
+		.flags = flags
+	};
+	size_t total = 0;
+	int ret = 0;
+	bool failed = false;
 
-	while (nr_vecs) {
+	while (iov_iter_count(from) && !failed) {
-		unsigned long off, npages;
+		struct page *pages[16];
-		struct iovec entry;
+		ssize_t copied;
-		void __user *base;
+		size_t start;
-		size_t len;
+		int n;
-		int i;
 
-		error = -EFAULT;
+		copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
-		if (copy_from_user(&entry, iov, sizeof(entry)))
+		if (copied <= 0) {
+			ret = copied;
 			break;
-
-		base = entry.iov_base;
-		len = entry.iov_len;
-
-		/*
-		 * Sanity check this iovec. 0 read succeeds.
-		 */
-		error = 0;
-		if (unlikely(!len))
-			break;
-		error = -EFAULT;
-		if (!access_ok(VERIFY_READ, base, len))
-			break;
-
-		/*
-		 * Get this base offset and number of pages, then map
-		 * in the user pages.
-		 */
-		off = (unsigned long) base & ~PAGE_MASK;
-
-		/*
-		 * If asked for alignment, the offset must be zero and the
-		 * length a multiple of the PAGE_SIZE.
-		 */
-		error = -EINVAL;
-		if (aligned && (off || len & ~PAGE_MASK))
-			break;
-
-		npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
-		if (npages > pipe_buffers - buffers)
-			npages = pipe_buffers - buffers;
-
-		error = get_user_pages_fast((unsigned long)base, npages,
-					0, &pages[buffers]);
-
-		if (unlikely(error <= 0))
-			break;
-
-		/*
-		 * Fill this contiguous range into the partial page map.
-		 */
-		for (i = 0; i < error; i++) {
-			const int plen = min_t(size_t, len, PAGE_SIZE - off);
-
-			partial[buffers].offset = off;
-			partial[buffers].len = plen;
-
-			off = 0;
-			len -= plen;
-			buffers++;
 		}
 
-		/*
+		for (n = 0; copied; n++, start = 0) {
-		 * We didn't complete this iov, stop here since it probably
+			int size = min_t(int, copied, PAGE_SIZE - start);
-		 * means we have to move some of this into a pipe to
+			if (!failed) {
-		 * be able to continue.
+				buf.page = pages[n];
-		 */
+				buf.offset = start;
-		if (len)
+				buf.len = size;
-			break;
+				ret = add_to_pipe(pipe, &buf);
-
+				if (unlikely(ret < 0)) {
-		/*
+					failed = true;
-		 * Don't continue if we mapped fewer pages than we asked for,
+				} else {
-		 * or if we mapped the max number of pages that we have
+					iov_iter_advance(from, ret);
-		 * room for.
+					total += ret;
-		 */
-		if (error < npages || buffers == pipe_buffers)
-			break;
-
-		nr_vecs--;
-		iov++;
 				}
-
+			} else {
-	if (buffers)
+				put_page(pages[n]);
-		return buffers;
+			}
-
+			copied -= size;
-	return error;
+		}
+	}
+	return total ? total : ret;
 }
 
 static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
@@ -1590,38 +1305,36 @@ static long vmsplice_to_user(struct file *file, const struct iovec __user *uiov,
  * as splice-from-memory, where the regular splice is splice-from-file (or
  * to file). In both cases the output is a pipe, naturally.
  */
-static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
+static long vmsplice_to_pipe(struct file *file, const struct iovec __user *uiov,
 			     unsigned long nr_segs, unsigned int flags)
 {
 	struct pipe_inode_info *pipe;
-	struct page *pages[PIPE_DEF_BUFFERS];
+	struct iovec iovstack[UIO_FASTIOV];
-	struct partial_page partial[PIPE_DEF_BUFFERS];
+	struct iovec *iov = iovstack;
-	struct splice_pipe_desc spd = {
+	struct iov_iter from;
-		.pages = pages,
-		.partial = partial,
-		.nr_pages_max = PIPE_DEF_BUFFERS,
-		.flags = flags,
-		.ops = &user_page_pipe_buf_ops,
-		.spd_release = spd_release_page,
-	};
 	long ret;
+	unsigned buf_flag = 0;
+
+	if (flags & SPLICE_F_GIFT)
+		buf_flag = PIPE_BUF_FLAG_GIFT;
 
 	pipe = get_pipe_info(file);
 	if (!pipe)
 		return -EBADF;
 
-	if (splice_grow_spd(pipe, &spd))
+	ret = import_iovec(WRITE, uiov, nr_segs,
-		return -ENOMEM;
+			   ARRAY_SIZE(iovstack), &iov, &from);
+	if (ret < 0)
+		return ret;
 
-	spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages,
+	pipe_lock(pipe);
-					    spd.partial, false,
+	ret = wait_for_space(pipe, flags);
-					    spd.nr_pages_max);
+	if (!ret)
-	if (spd.nr_pages <= 0)
+		ret = iter_to_pipe(&from, pipe, buf_flag);
-		ret = spd.nr_pages;
+	pipe_unlock(pipe);
-	else
+	if (ret > 0)
-		ret = splice_to_pipe(pipe, &spd);
+		wakeup_pipe_readers(pipe);
-
+	kfree(iov);
-	splice_shrink_spd(&spd);
 	return ret;
 }
 
@@ -1876,7 +1589,7 @@ static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
 			 * Get a reference to this pipe buffer,
 			 * so we can copy the contents over.
 			 */
-			ibuf->ops->get(ipipe, ibuf);
+			pipe_buf_get(ipipe, ibuf);
 			*obuf = *ibuf;
 
 			/*
@@ -1948,7 +1661,7 @@ static int link_pipe(struct pipe_inode_info *ipipe,
 		 * Get a reference to this pipe buffer,
 		 * so we can copy the contents over.
 		 */
-		ibuf->ops->get(ipipe, ibuf);
+		pipe_buf_get(ipipe, ibuf);
 
 		obuf = opipe->bufs + nbuf;
 		*obuf = *ibuf;

fs/xfs/xfs_file.c

@@ -393,45 +393,6 @@ xfs_file_read_iter(
 	return ret;
 }
 
-STATIC ssize_t
-xfs_file_splice_read(
-	struct file		*infilp,
-	loff_t			*ppos,
-	struct pipe_inode_info	*pipe,
-	size_t			count,
-	unsigned int		flags)
-{
-	struct xfs_inode	*ip = XFS_I(infilp->f_mapping->host);
-	ssize_t			ret;
-
-	XFS_STATS_INC(ip->i_mount, xs_read_calls);
-
-	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
-		return -EIO;
-
-	trace_xfs_file_splice_read(ip, count, *ppos);
-
-	/*
-	 * DAX inodes cannot ues the page cache for splice, so we have to push
-	 * them through the VFS IO path. This means it goes through
-	 * ->read_iter, which for us takes the XFS_IOLOCK_SHARED. Hence we
-	 * cannot lock the splice operation at this level for DAX inodes.
-	 */
-	if (IS_DAX(VFS_I(ip))) {
-		ret = default_file_splice_read(infilp, ppos, pipe, count,
-					       flags);
-		goto out;
-	}
-
-	xfs_rw_ilock(ip, XFS_IOLOCK_SHARED);
-	ret = generic_file_splice_read(infilp, ppos, pipe, count, flags);
-	xfs_rw_iunlock(ip, XFS_IOLOCK_SHARED);
-out:
-	if (ret > 0)
-		XFS_STATS_ADD(ip->i_mount, xs_read_bytes, ret);
-	return ret;
-}
-
 /*
  * Zero any on disk space between the current EOF and the new, larger EOF.
  *
@@ -1608,7 +1569,7 @@ const struct file_operations xfs_file_operations = {
 	.llseek		= xfs_file_llseek,
 	.read_iter	= xfs_file_read_iter,
 	.write_iter	= xfs_file_write_iter,
-	.splice_read	= xfs_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.unlocked_ioctl	= xfs_file_ioctl,
 #ifdef CONFIG_COMPAT

fs/xfs/xfs_trace.h

@@ -1170,7 +1170,6 @@ DEFINE_RW_EVENT(xfs_file_dax_read);
 DEFINE_RW_EVENT(xfs_file_buffered_write);
 DEFINE_RW_EVENT(xfs_file_direct_write);
 DEFINE_RW_EVENT(xfs_file_dax_write);
-DEFINE_RW_EVENT(xfs_file_splice_read);
 
 DECLARE_EVENT_CLASS(xfs_page_class,
 	TP_PROTO(struct inode *inode, struct page *page, unsigned long off,

include/linux/fs.h

@@ -2794,8 +2794,6 @@ extern void block_sync_page(struct page *page);
 /* fs/splice.c */
 extern ssize_t generic_file_splice_read(struct file *, loff_t *,
 		struct pipe_inode_info *, size_t, unsigned int);
-extern ssize_t default_file_splice_read(struct file *, loff_t *,
-		struct pipe_inode_info *, size_t, unsigned int);
 extern ssize_t iter_file_splice_write(struct pipe_inode_info *,
 		struct file *, loff_t *, size_t, unsigned int);
 extern ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe,

include/linux/pipe_fs_i.h

@@ -66,15 +66,10 @@ struct pipe_inode_info {
  *
  * ->confirm()
  *	->steal()
- *	...
- *	->map()
- *	...
- *	->unmap()
  *
- * That is, ->map() must be called on a confirmed buffer,
+ * That is, ->steal() must be called on a confirmed buffer.
- * same goes for ->steal(). See below for the meaning of each
+ * See below for the meaning of each operation. Also see kerneldoc
- * operation. Also see kerneldoc in fs/pipe.c for the pipe
+ * in fs/pipe.c for the pipe and generic variants of these hooks.
- * and generic variants of these hooks.
  */
 struct pipe_buf_operations {
 	/*
@@ -115,6 +110,53 @@ struct pipe_buf_operations {
 	void (*get)(struct pipe_inode_info *, struct pipe_buffer *);
 };
 
+/**
+ * pipe_buf_get - get a reference to a pipe_buffer
+ * @pipe:	the pipe that the buffer belongs to
+ * @buf:	the buffer to get a reference to
+ */
+static inline void pipe_buf_get(struct pipe_inode_info *pipe,
+				struct pipe_buffer *buf)
+{
+	buf->ops->get(pipe, buf);
+}
+
+/**
+ * pipe_buf_release - put a reference to a pipe_buffer
+ * @pipe:	the pipe that the buffer belongs to
+ * @buf:	the buffer to put a reference to
+ */
+static inline void pipe_buf_release(struct pipe_inode_info *pipe,
+				    struct pipe_buffer *buf)
+{
+	const struct pipe_buf_operations *ops = buf->ops;
+
+	buf->ops = NULL;
+	ops->release(pipe, buf);
+}
+
+/**
+ * pipe_buf_confirm - verify contents of the pipe buffer
+ * @pipe:	the pipe that the buffer belongs to
+ * @buf:	the buffer to confirm
+ */
+static inline int pipe_buf_confirm(struct pipe_inode_info *pipe,
+				   struct pipe_buffer *buf)
+{
+	return buf->ops->confirm(pipe, buf);
+}
+
+/**
+ * pipe_buf_steal - attempt to take ownership of a pipe_buffer
+ * @pipe:	the pipe that the buffer belongs to
+ * @buf:	the buffer to attempt to steal
+ */
+static inline int pipe_buf_steal(struct pipe_inode_info *pipe,
+				 struct pipe_buffer *buf)
+{
+	return buf->ops->steal(pipe, buf);
+}
+
 /* Differs from PIPE_BUF in that PIPE_SIZE is the length of the actual
    memory allocation, whereas PIPE_BUF makes atomicity guarantees.  */
 #define PIPE_SIZE		PAGE_SIZE
@@ -129,7 +171,6 @@ extern unsigned long pipe_user_pages_hard;
 extern unsigned long pipe_user_pages_soft;
 int pipe_proc_fn(struct ctl_table *, int, void __user *, size_t *, loff_t *);
 
-
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe);
 

include/linux/skbuff.h

@@ -3064,15 +3064,9 @@ int skb_copy_bits(const struct sk_buff *skb, int offset, void *to, int len);
 int skb_store_bits(struct sk_buff *skb, int offset, const void *from, int len);
 __wsum skb_copy_and_csum_bits(const struct sk_buff *skb, int offset, u8 *to,
 			      int len, __wsum csum);
-ssize_t skb_socket_splice(struct sock *sk,
-			  struct pipe_inode_info *pipe,
-			  struct splice_pipe_desc *spd);
 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
 		    struct pipe_inode_info *pipe, unsigned int len,
-		    unsigned int flags,
+		    unsigned int flags);
-		    ssize_t (*splice_cb)(struct sock *,
-					 struct pipe_inode_info *,
-					 struct splice_pipe_desc *));
 void skb_copy_and_csum_dev(const struct sk_buff *skb, u8 *to);
 unsigned int skb_zerocopy_headlen(const struct sk_buff *from);
 int skb_zerocopy(struct sk_buff *to, struct sk_buff *from,

include/linux/splice.h

@@ -72,6 +72,8 @@ extern ssize_t __splice_from_pipe(struct pipe_inode_info *,
 				  struct splice_desc *, splice_actor *);
 extern ssize_t splice_to_pipe(struct pipe_inode_info *,
 			      struct splice_pipe_desc *);
+extern ssize_t add_to_pipe(struct pipe_inode_info *,
+			      struct pipe_buffer *);
 extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
 				      splice_direct_actor *);
 
@@ -83,4 +85,5 @@ extern void splice_shrink_spd(struct splice_pipe_desc *);
 extern void spd_release_page(struct splice_pipe_desc *, unsigned int);
 
 extern const struct pipe_buf_operations page_cache_pipe_buf_ops;
+extern const struct pipe_buf_operations default_pipe_buf_ops;
 #endif

include/linux/uio.h

@@ -13,6 +13,7 @@
 #include <uapi/linux/uio.h>
 
 struct page;
+struct pipe_inode_info;
 
 struct kvec {
 	void *iov_base; /* and that should *never* hold a userland pointer */
@@ -23,6 +24,7 @@ enum {
 	ITER_IOVEC = 0,
 	ITER_KVEC = 2,
 	ITER_BVEC = 4,
+	ITER_PIPE = 8,
 };
 
 struct iov_iter {
@@ -33,8 +35,12 @@ struct iov_iter {
 		const struct iovec *iov;
 		const struct kvec *kvec;
 		const struct bio_vec *bvec;
+		struct pipe_inode_info *pipe;
 	};
+	union {
 		unsigned long nr_segs;
+		int idx;
+	};
 };
 
 /*
@@ -64,7 +70,7 @@ static inline struct iovec iov_iter_iovec(const struct iov_iter *iter)
 }
 
 #define iov_for_each(iov, iter, start)				\
-	if (!((start).type & ITER_BVEC))			\
+	if (!((start).type & (ITER_BVEC | ITER_PIPE)))		\
 	for (iter = (start);					\
 	     (iter).count &&					\
 	     ((iov = iov_iter_iovec(&(iter))), 1);		\
@@ -94,6 +100,8 @@ void iov_iter_kvec(struct iov_iter *i, int direction, const struct kvec *kvec,
 			unsigned long nr_segs, size_t count);
 void iov_iter_bvec(struct iov_iter *i, int direction, const struct bio_vec *bvec,
 			unsigned long nr_segs, size_t count);
+void iov_iter_pipe(struct iov_iter *i, int direction, struct pipe_inode_info *pipe,
+			size_t count);
 ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages,
 			size_t maxsize, unsigned maxpages, size_t *start);
 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages,
@@ -109,7 +117,7 @@ static inline size_t iov_iter_count(struct iov_iter *i)
 
 static inline bool iter_is_iovec(struct iov_iter *i)
 {
-	return !(i->type & (ITER_BVEC | ITER_KVEC));
+	return !(i->type & (ITER_BVEC | ITER_KVEC | ITER_PIPE));
 }
 
 /*

kernel/relay.c

@@ -1108,51 +1108,23 @@ static size_t relay_file_read_end_pos(struct rchan_buf *buf,
 	return end_pos;
 }
 
-/*
+static ssize_t relay_file_read(struct file *filp,
- *	subbuf_read_actor - read up to one subbuf's worth of data
+			       char __user *buffer,
- */
+			       size_t count,
-static int subbuf_read_actor(size_t read_start,
+			       loff_t *ppos)
-			     struct rchan_buf *buf,
-			     size_t avail,
-			     read_descriptor_t *desc)
-{
-	void *from;
-	int ret = 0;
-
-	from = buf->start + read_start;
-	ret = avail;
-	if (copy_to_user(desc->arg.buf, from, avail)) {
-		desc->error = -EFAULT;
-		ret = 0;
-	}
-	desc->arg.data += ret;
-	desc->written += ret;
-	desc->count -= ret;
-
-	return ret;
-}
-
-typedef int (*subbuf_actor_t) (size_t read_start,
-			       struct rchan_buf *buf,
-			       size_t avail,
-			       read_descriptor_t *desc);
-
-/*
- *	relay_file_read_subbufs - read count bytes, bridging subbuf boundaries
- */
-static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
-					subbuf_actor_t subbuf_actor,
-					read_descriptor_t *desc)
 {
 	struct rchan_buf *buf = filp->private_data;
 	size_t read_start, avail;
+	size_t written = 0;
 	int ret;
 
-	if (!desc->count)
+	if (!count)
 		return 0;
 
 	inode_lock(file_inode(filp));
 	do {
+		void *from;
+
 		if (!relay_file_read_avail(buf, *ppos))
 			break;
 
@@ -1161,32 +1133,22 @@ static ssize_t relay_file_read_subbufs(struct file *filp, loff_t *ppos,
 		if (!avail)
 			break;
 
-		avail = min(desc->count, avail);
+		avail = min(count, avail);
-		ret = subbuf_actor(read_start, buf, avail, desc);
+		from = buf->start + read_start;
-		if (desc->error < 0)
+		ret = avail;
+		if (copy_to_user(buffer, from, avail))
 			break;
 
-		if (ret) {
+		buffer += ret;
+		written += ret;
+		count -= ret;
+
 		relay_file_read_consume(buf, read_start, ret);
 		*ppos = relay_file_read_end_pos(buf, read_start, ret);
-		}
+	} while (count);
-	} while (desc->count && ret);
 	inode_unlock(file_inode(filp));
 
-	return desc->written;
+	return written;
-}
-
-static ssize_t relay_file_read(struct file *filp,
-			       char __user *buffer,
-			       size_t count,
-			       loff_t *ppos)
-{
-	read_descriptor_t desc;
-	desc.written = 0;
-	desc.count = count;
-	desc.arg.buf = buffer;
-	desc.error = 0;
-	return relay_file_read_subbufs(filp, ppos, subbuf_read_actor, &desc);
 }
 
 static void relay_consume_bytes(struct rchan_buf *rbuf, int bytes_consumed)

lib/iov_iter.c

@@ -3,8 +3,11 @@
 #include <linux/pagemap.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/splice.h>
 #include <net/checksum.h>
 
+#define PIPE_PARANOIA /* for now */
+
 #define iterate_iovec(i, n, __v, __p, skip, STEP) {	\
 	size_t left;					\
 	size_t wanted = n;				\
@@ -290,6 +293,93 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t
 	return wanted - bytes;
 }
 
+#ifdef PIPE_PARANOIA
+static bool sanity(const struct iov_iter *i)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	int idx = i->idx;
+	int next = pipe->curbuf + pipe->nrbufs;
+	if (i->iov_offset) {
+		struct pipe_buffer *p;
+		if (unlikely(!pipe->nrbufs))
+			goto Bad;	// pipe must be non-empty
+		if (unlikely(idx != ((next - 1) & (pipe->buffers - 1))))
+			goto Bad;	// must be at the last buffer...
+
+		p = &pipe->bufs[idx];
+		if (unlikely(p->offset + p->len != i->iov_offset))
+			goto Bad;	// ... at the end of segment
+	} else {
+		if (idx != (next & (pipe->buffers - 1)))
+			goto Bad;	// must be right after the last buffer
+	}
+	return true;
+Bad:
+	printk(KERN_ERR "idx = %d, offset = %zd\n", i->idx, i->iov_offset);
+	printk(KERN_ERR "curbuf = %d, nrbufs = %d, buffers = %d\n",
+			pipe->curbuf, pipe->nrbufs, pipe->buffers);
+	for (idx = 0; idx < pipe->buffers; idx++)
+		printk(KERN_ERR "[%p %p %d %d]\n",
+			pipe->bufs[idx].ops,
+			pipe->bufs[idx].page,
+			pipe->bufs[idx].offset,
+			pipe->bufs[idx].len);
+	WARN_ON(1);
+	return false;
+}
+#else
+#define sanity(i) true
+#endif
+
+static inline int next_idx(int idx, struct pipe_inode_info *pipe)
+{
+	return (idx + 1) & (pipe->buffers - 1);
+}
+
+static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
+			 struct iov_iter *i)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	struct pipe_buffer *buf;
+	size_t off;
+	int idx;
+
+	if (unlikely(bytes > i->count))
+		bytes = i->count;
+
+	if (unlikely(!bytes))
+		return 0;
+
+	if (!sanity(i))
+		return 0;
+
+	off = i->iov_offset;
+	idx = i->idx;
+	buf = &pipe->bufs[idx];
+	if (off) {
+		if (offset == off && buf->page == page) {
+			/* merge with the last one */
+			buf->len += bytes;
+			i->iov_offset += bytes;
+			goto out;
+		}
+		idx = next_idx(idx, pipe);
+		buf = &pipe->bufs[idx];
+	}
+	if (idx == pipe->curbuf && pipe->nrbufs)
+		return 0;
+	pipe->nrbufs++;
+	buf->ops = &page_cache_pipe_buf_ops;
+	get_page(buf->page = page);
+	buf->offset = offset;
+	buf->len = bytes;
+	i->iov_offset = offset + bytes;
+	i->idx = idx;
+out:
+	i->count -= bytes;
+	return bytes;
+}
+
 /*
  * Fault in one or more iovecs of the given iov_iter, to a maximum length of
  * bytes.  For each iovec, fault in each page that constitutes the iovec.
@@ -356,9 +446,98 @@ static void memzero_page(struct page *page, size_t offset, size_t len)
 	kunmap_atomic(addr);
 }
 
+static inline bool allocated(struct pipe_buffer *buf)
+{
+	return buf->ops == &default_pipe_buf_ops;
+}
+
+static inline void data_start(const struct iov_iter *i, int *idxp, size_t *offp)
+{
+	size_t off = i->iov_offset;
+	int idx = i->idx;
+	if (off && (!allocated(&i->pipe->bufs[idx]) || off == PAGE_SIZE)) {
+		idx = next_idx(idx, i->pipe);
+		off = 0;
+	}
+	*idxp = idx;
+	*offp = off;
+}
+
+static size_t push_pipe(struct iov_iter *i, size_t size,
+			int *idxp, size_t *offp)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	size_t off;
+	int idx;
+	ssize_t left;
+
+	if (unlikely(size > i->count))
+		size = i->count;
+	if (unlikely(!size))
+		return 0;
+
+	left = size;
+	data_start(i, &idx, &off);
+	*idxp = idx;
+	*offp = off;
+	if (off) {
+		left -= PAGE_SIZE - off;
+		if (left <= 0) {
+			pipe->bufs[idx].len += size;
+			return size;
+		}
+		pipe->bufs[idx].len = PAGE_SIZE;
+		idx = next_idx(idx, pipe);
+	}
+	while (idx != pipe->curbuf || !pipe->nrbufs) {
+		struct page *page = alloc_page(GFP_USER);
+		if (!page)
+			break;
+		pipe->nrbufs++;
+		pipe->bufs[idx].ops = &default_pipe_buf_ops;
+		pipe->bufs[idx].page = page;
+		pipe->bufs[idx].offset = 0;
+		if (left <= PAGE_SIZE) {
+			pipe->bufs[idx].len = left;
+			return size;
+		}
+		pipe->bufs[idx].len = PAGE_SIZE;
+		left -= PAGE_SIZE;
+		idx = next_idx(idx, pipe);
+	}
+	return size - left;
+}
+
+static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
+				struct iov_iter *i)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	size_t n, off;
+	int idx;
+
+	if (!sanity(i))
+		return 0;
+
+	bytes = n = push_pipe(i, bytes, &idx, &off);
+	if (unlikely(!n))
+		return 0;
+	for ( ; n; idx = next_idx(idx, pipe), off = 0) {
+		size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
+		memcpy_to_page(pipe->bufs[idx].page, off, addr, chunk);
+		i->idx = idx;
+		i->iov_offset = off + chunk;
+		n -= chunk;
+		addr += chunk;
+	}
+	i->count -= bytes;
+	return bytes;
+}
+
 size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
 {
 	const char *from = addr;
+	if (unlikely(i->type & ITER_PIPE))
+		return copy_pipe_to_iter(addr, bytes, i);
 	iterate_and_advance(i, bytes, v,
 		__copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
 			       v.iov_len),
@@ -374,6 +553,10 @@ EXPORT_SYMBOL(copy_to_iter);
 size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return 0;
+	}
 	iterate_and_advance(i, bytes, v,
 		__copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
 				 v.iov_len),
@@ -389,6 +572,10 @@ EXPORT_SYMBOL(copy_from_iter);
 size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
 {
 	char *to = addr;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return 0;
+	}
 	iterate_and_advance(i, bytes, v,
 		__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
 					 v.iov_base, v.iov_len),
@@ -409,14 +596,20 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
 		size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
 		kunmap_atomic(kaddr);
 		return wanted;
-	} else
+	} else if (likely(!(i->type & ITER_PIPE)))
 		return copy_page_to_iter_iovec(page, offset, bytes, i);
+	else
+		return copy_page_to_iter_pipe(page, offset, bytes, i);
 }
 EXPORT_SYMBOL(copy_page_to_iter);
 
 size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
 			 struct iov_iter *i)
 {
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return 0;
+	}
 	if (i->type & (ITER_BVEC|ITER_KVEC)) {
 		void *kaddr = kmap_atomic(page);
 		size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
@@ -427,8 +620,34 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
 }
 EXPORT_SYMBOL(copy_page_from_iter);
 
+static size_t pipe_zero(size_t bytes, struct iov_iter *i)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	size_t n, off;
+	int idx;
+
+	if (!sanity(i))
+		return 0;
+
+	bytes = n = push_pipe(i, bytes, &idx, &off);
+	if (unlikely(!n))
+		return 0;
+
+	for ( ; n; idx = next_idx(idx, pipe), off = 0) {
+		size_t chunk = min_t(size_t, n, PAGE_SIZE - off);
+		memzero_page(pipe->bufs[idx].page, off, chunk);
+		i->idx = idx;
+		i->iov_offset = off + chunk;
+		n -= chunk;
+	}
+	i->count -= bytes;
+	return bytes;
+}
+
 size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
 {
+	if (unlikely(i->type & ITER_PIPE))
+		return pipe_zero(bytes, i);
 	iterate_and_advance(i, bytes, v,
 		__clear_user(v.iov_base, v.iov_len),
 		memzero_page(v.bv_page, v.bv_offset, v.bv_len),
@@ -443,6 +662,11 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 		struct iov_iter *i, unsigned long offset, size_t bytes)
 {
 	char *kaddr = kmap_atomic(page), *p = kaddr + offset;
+	if (unlikely(i->type & ITER_PIPE)) {
+		kunmap_atomic(kaddr);
+		WARN_ON(1);
+		return 0;
+	}
 	iterate_all_kinds(i, bytes, v,
 		__copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
 					  v.iov_base, v.iov_len),
@@ -455,8 +679,49 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
 }
 EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
 
+static void pipe_advance(struct iov_iter *i, size_t size)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	struct pipe_buffer *buf;
+	int idx = i->idx;
+	size_t off = i->iov_offset;
+	
+	if (unlikely(i->count < size))
+		size = i->count;
+
+	if (size) {
+		if (off) /* make it relative to the beginning of buffer */
+			size += off - pipe->bufs[idx].offset;
+		while (1) {
+			buf = &pipe->bufs[idx];
+			if (size <= buf->len)
+				break;
+			size -= buf->len;
+			idx = next_idx(idx, pipe);
+		}
+		buf->len = size;
+		i->idx = idx;
+		off = i->iov_offset = buf->offset + size;
+	}
+	if (off)
+		idx = next_idx(idx, pipe);
+	if (pipe->nrbufs) {
+		int unused = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+		/* [curbuf,unused) is in use.  Free [idx,unused) */
+		while (idx != unused) {
+			pipe_buf_release(pipe, &pipe->bufs[idx]);
+			idx = next_idx(idx, pipe);
+			pipe->nrbufs--;
+		}
+	}
+}
+
 void iov_iter_advance(struct iov_iter *i, size_t size)
 {
+	if (unlikely(i->type & ITER_PIPE)) {
+		pipe_advance(i, size);
+		return;
+	}
 	iterate_and_advance(i, size, v, 0, 0, 0)
 }
 EXPORT_SYMBOL(iov_iter_advance);
@@ -466,6 +731,8 @@ EXPORT_SYMBOL(iov_iter_advance);
  */
 size_t iov_iter_single_seg_count(const struct iov_iter *i)
 {
+	if (unlikely(i->type & ITER_PIPE))
+		return i->count;	// it is a silly place, anyway
 	if (i->nr_segs == 1)
 		return i->count;
 	else if (i->type & ITER_BVEC)
@@ -501,6 +768,19 @@ void iov_iter_bvec(struct iov_iter *i, int direction,
 }
 EXPORT_SYMBOL(iov_iter_bvec);
 
+void iov_iter_pipe(struct iov_iter *i, int direction,
+			struct pipe_inode_info *pipe,
+			size_t count)
+{
+	BUG_ON(direction != ITER_PIPE);
+	i->type = direction;
+	i->pipe = pipe;
+	i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
+	i->iov_offset = 0;
+	i->count = count;
+}
+EXPORT_SYMBOL(iov_iter_pipe);
+
 unsigned long iov_iter_alignment(const struct iov_iter *i)
 {
 	unsigned long res = 0;
@@ -509,6 +789,11 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
 	if (!size)
 		return 0;
 
+	if (unlikely(i->type & ITER_PIPE)) {
+		if (i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
+			return size | i->iov_offset;
+		return size;
+	}
 	iterate_all_kinds(i, size, v,
 		(res |= (unsigned long)v.iov_base | v.iov_len, 0),
 		res |= v.bv_offset | v.bv_len,
@@ -525,6 +810,11 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
 	if (!size)
 		return 0;
 
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return ~0U;
+	}
+
 	iterate_all_kinds(i, size, v,
 		(res |= (!res ? 0 : (unsigned long)v.iov_base) |
 			(size != v.iov_len ? size : 0), 0),
@@ -537,6 +827,47 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
 }
 EXPORT_SYMBOL(iov_iter_gap_alignment);
 
+static inline size_t __pipe_get_pages(struct iov_iter *i,
+				size_t maxsize,
+				struct page **pages,
+				int idx,
+				size_t *start)
+{
+	struct pipe_inode_info *pipe = i->pipe;
+	size_t n = push_pipe(i, maxsize, &idx, start);
+	if (!n)
+		return -EFAULT;
+
+	maxsize = n;
+	n += *start;
+	while (n >= PAGE_SIZE) {
+		get_page(*pages++ = pipe->bufs[idx].page);
+		idx = next_idx(idx, pipe);
+		n -= PAGE_SIZE;
+	}
+
+	return maxsize;
+}
+
+static ssize_t pipe_get_pages(struct iov_iter *i,
+		   struct page **pages, size_t maxsize, unsigned maxpages,
+		   size_t *start)
+{
+	unsigned npages;
+	size_t capacity;
+	int idx;
+
+	if (!sanity(i))
+		return -EFAULT;
+
+	data_start(i, &idx, start);
+	/* some of this one + all after this one */
+	npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
+	capacity = min(npages,maxpages) * PAGE_SIZE - *start;
+
+	return __pipe_get_pages(i, min(maxsize, capacity), pages, idx, start);
+}
+
 ssize_t iov_iter_get_pages(struct iov_iter *i,
 		   struct page **pages, size_t maxsize, unsigned maxpages,
 		   size_t *start)
@@ -547,6 +878,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
 	if (!maxsize)
 		return 0;
 
+	if (unlikely(i->type & ITER_PIPE))
+		return pipe_get_pages(i, pages, maxsize, maxpages, start);
 	iterate_all_kinds(i, maxsize, v, ({
 		unsigned long addr = (unsigned long)v.iov_base;
 		size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -582,6 +915,37 @@ static struct page **get_pages_array(size_t n)
 	return p;
 }
 
+static ssize_t pipe_get_pages_alloc(struct iov_iter *i,
+		   struct page ***pages, size_t maxsize,
+		   size_t *start)
+{
+	struct page **p;
+	size_t n;
+	int idx;
+	int npages;
+
+	if (!sanity(i))
+		return -EFAULT;
+
+	data_start(i, &idx, start);
+	/* some of this one + all after this one */
+	npages = ((i->pipe->curbuf - idx - 1) & (i->pipe->buffers - 1)) + 1;
+	n = npages * PAGE_SIZE - *start;
+	if (maxsize > n)
+		maxsize = n;
+	else
+		npages = DIV_ROUND_UP(maxsize + *start, PAGE_SIZE);
+	p = get_pages_array(npages);
+	if (!p)
+		return -ENOMEM;
+	n = __pipe_get_pages(i, maxsize, p, idx, start);
+	if (n > 0)
+		*pages = p;
+	else
+		kvfree(p);
+	return n;
+}
+
 ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 		   struct page ***pages, size_t maxsize,
 		   size_t *start)
@@ -594,6 +958,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 	if (!maxsize)
 		return 0;
 
+	if (unlikely(i->type & ITER_PIPE))
+		return pipe_get_pages_alloc(i, pages, maxsize, start);
 	iterate_all_kinds(i, maxsize, v, ({
 		unsigned long addr = (unsigned long)v.iov_base;
 		size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -635,6 +1001,10 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
 	__wsum sum, next;
 	size_t off = 0;
 	sum = *csum;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return 0;
+	}
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;
 		next = csum_and_copy_from_user(v.iov_base, 
@@ -673,6 +1043,10 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
 	__wsum sum, next;
 	size_t off = 0;
 	sum = *csum;
+	if (unlikely(i->type & ITER_PIPE)) {
+		WARN_ON(1);	/* for now */
+		return 0;
+	}
 	iterate_and_advance(i, bytes, v, ({
 		int err = 0;
 		next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
@@ -712,7 +1086,20 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
 	if (!size)
 		return 0;
 
-	iterate_all_kinds(i, size, v, ({
+	if (unlikely(i->type & ITER_PIPE)) {
+		struct pipe_inode_info *pipe = i->pipe;
+		size_t off;
+		int idx;
+
+		if (!sanity(i))
+			return 0;
+
+		data_start(i, &idx, &off);
+		/* some of this one + all after this one */
+		npages = ((pipe->curbuf - idx - 1) & (pipe->buffers - 1)) + 1;
+		if (npages >= maxpages)
+			return maxpages;
+	} else iterate_all_kinds(i, size, v, ({
 		unsigned long p = (unsigned long)v.iov_base;
 		npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
 			- p / PAGE_SIZE;
@@ -737,6 +1124,10 @@ EXPORT_SYMBOL(iov_iter_npages);
 const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
 {
 	*new = *old;
+	if (unlikely(new->type & ITER_PIPE)) {
+		WARN_ON(1);
+		return NULL;
+	}
 	if (new->type & ITER_BVEC)
 		return new->bvec = kmemdup(new->bvec,
 				    new->nr_segs * sizeof(struct bio_vec),

mm/shmem.c

@@ -2311,119 +2311,6 @@ static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
 	return retval ? retval : error;
 }
 
-static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,
-				struct pipe_inode_info *pipe, size_t len,
-				unsigned int flags)
-{
-	struct address_space *mapping = in->f_mapping;
-	struct inode *inode = mapping->host;
-	unsigned int loff, nr_pages, req_pages;
-	struct page *pages[PIPE_DEF_BUFFERS];
-	struct partial_page partial[PIPE_DEF_BUFFERS];
-	struct page *page;
-	pgoff_t index, end_index;
-	loff_t isize, left;
-	int error, page_nr;
-	struct splice_pipe_desc spd = {
-		.pages = pages,
-		.partial = partial,
-		.nr_pages_max = PIPE_DEF_BUFFERS,
-		.flags = flags,
-		.ops = &page_cache_pipe_buf_ops,
-		.spd_release = spd_release_page,
-	};
-
-	isize = i_size_read(inode);
-	if (unlikely(*ppos >= isize))
-		return 0;
-
-	left = isize - *ppos;
-	if (unlikely(left < len))
-		len = left;
-
-	if (splice_grow_spd(pipe, &spd))
-		return -ENOMEM;
-
-	index = *ppos >> PAGE_SHIFT;
-	loff = *ppos & ~PAGE_MASK;
-	req_pages = (len + loff + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	nr_pages = min(req_pages, spd.nr_pages_max);
-
-	spd.nr_pages = find_get_pages_contig(mapping, index,
-						nr_pages, spd.pages);
-	index += spd.nr_pages;
-	error = 0;
-
-	while (spd.nr_pages < nr_pages) {
-		error = shmem_getpage(inode, index, &page, SGP_CACHE);
-		if (error)
-			break;
-		unlock_page(page);
-		spd.pages[spd.nr_pages++] = page;
-		index++;
-	}
-
-	index = *ppos >> PAGE_SHIFT;
-	nr_pages = spd.nr_pages;
-	spd.nr_pages = 0;
-
-	for (page_nr = 0; page_nr < nr_pages; page_nr++) {
-		unsigned int this_len;
-
-		if (!len)
-			break;
-
-		this_len = min_t(unsigned long, len, PAGE_SIZE - loff);
-		page = spd.pages[page_nr];
-
-		if (!PageUptodate(page) || page->mapping != mapping) {
-			error = shmem_getpage(inode, index, &page, SGP_CACHE);
-			if (error)
-				break;
-			unlock_page(page);
-			put_page(spd.pages[page_nr]);
-			spd.pages[page_nr] = page;
-		}
-
-		isize = i_size_read(inode);
-		end_index = (isize - 1) >> PAGE_SHIFT;
-		if (unlikely(!isize || index > end_index))
-			break;
-
-		if (end_index == index) {
-			unsigned int plen;
-
-			plen = ((isize - 1) & ~PAGE_MASK) + 1;
-			if (plen <= loff)
-				break;
-
-			this_len = min(this_len, plen - loff);
-			len = this_len;
-		}
-
-		spd.partial[page_nr].offset = loff;
-		spd.partial[page_nr].len = this_len;
-		len -= this_len;
-		loff = 0;
-		spd.nr_pages++;
-		index++;
-	}
-
-	while (page_nr < nr_pages)
-		put_page(spd.pages[page_nr++]);
-
-	if (spd.nr_pages)
-		error = splice_to_pipe(pipe, &spd);
-
-	splice_shrink_spd(&spd);
-
-	if (error > 0) {
-		*ppos += error;
-		file_accessed(in);
-	}
-	return error;
-}
-
 /*
  * llseek SEEK_DATA or SEEK_HOLE through the radix_tree.
  */
@@ -3786,7 +3673,7 @@ static const struct file_operations shmem_file_operations = {
 	.read_iter	= shmem_file_read_iter,
 	.write_iter	= generic_file_write_iter,
 	.fsync		= noop_fsync,
-	.splice_read	= shmem_file_splice_read,
+	.splice_read	= generic_file_splice_read,
 	.splice_write	= iter_file_splice_write,
 	.fallocate	= shmem_fallocate,
 #endif

net/core/skbuff.c

@@ -1962,37 +1962,13 @@ static bool __skb_splice_bits(struct sk_buff *skb, struct pipe_inode_info *pipe,
 	return false;
 }
 
-ssize_t skb_socket_splice(struct sock *sk,
-			  struct pipe_inode_info *pipe,
-			  struct splice_pipe_desc *spd)
-{
-	int ret;
-
-	/* Drop the socket lock, otherwise we have reverse
-	 * locking dependencies between sk_lock and i_mutex
-	 * here as compared to sendfile(). We enter here
-	 * with the socket lock held, and splice_to_pipe() will
-	 * grab the pipe inode lock. For sendfile() emulation,
-	 * we call into ->sendpage() with the i_mutex lock held
-	 * and networking will grab the socket lock.
-	 */
-	release_sock(sk);
-	ret = splice_to_pipe(pipe, spd);
-	lock_sock(sk);
-
-	return ret;
-}
-
 /*
  * Map data from the skb to a pipe. Should handle both the linear part,
  * the fragments, and the frag list.
  */
 int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
 		    struct pipe_inode_info *pipe, unsigned int tlen,
-		    unsigned int flags,
+		    unsigned int flags)
-		    ssize_t (*splice_cb)(struct sock *,
-					 struct pipe_inode_info *,
-					 struct splice_pipe_desc *))
 {
 	struct partial_page partial[MAX_SKB_FRAGS];
 	struct page *pages[MAX_SKB_FRAGS];
@@ -2009,7 +1985,7 @@ int skb_splice_bits(struct sk_buff *skb, struct sock *sk, unsigned int offset,
 	__skb_splice_bits(skb, pipe, &offset, &tlen, &spd, sk);
 
 	if (spd.nr_pages)
-		ret = splice_cb(sk, pipe, &spd);
+		ret = splice_to_pipe(pipe, &spd);
 
 	return ret;
 }

net/ipv4/tcp.c

@@ -691,8 +691,7 @@ static int tcp_splice_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
 	int ret;
 
 	ret = skb_splice_bits(skb, skb->sk, offset, tss->pipe,
-			      min(rd_desc->count, len), tss->flags,
+			      min(rd_desc->count, len), tss->flags);
-			      skb_socket_splice);
 	if (ret > 0)
 		rd_desc->count -= ret;
 	return ret;

net/kcm/kcmsock.c

@@ -1160,19 +1160,6 @@ static int kcm_recvmsg(struct socket *sock, struct msghdr *msg,
 	return copied ? : err;
 }
 
-static ssize_t kcm_sock_splice(struct sock *sk,
-			       struct pipe_inode_info *pipe,
-			       struct splice_pipe_desc *spd)
-{
-	int ret;
-
-	release_sock(sk);
-	ret = splice_to_pipe(pipe, spd);
-	lock_sock(sk);
-
-	return ret;
-}
-
 static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
 			       struct pipe_inode_info *pipe, size_t len,
 			       unsigned int flags)
@@ -1202,8 +1189,7 @@ static ssize_t kcm_splice_read(struct socket *sock, loff_t *ppos,
 	if (len > rxm->full_len)
 		len = rxm->full_len;
 
-	copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags,
+	copied = skb_splice_bits(skb, sk, rxm->offset, pipe, len, flags);
-				 kcm_sock_splice);
 	if (copied < 0) {
 		err = copied;
 		goto err_out;

net/unix/af_unix.c

@@ -2475,28 +2475,13 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg,
 	return unix_stream_read_generic(&state);
 }
 
-static ssize_t skb_unix_socket_splice(struct sock *sk,
-				      struct pipe_inode_info *pipe,
-				      struct splice_pipe_desc *spd)
-{
-	int ret;
-	struct unix_sock *u = unix_sk(sk);
-
-	mutex_unlock(&u->iolock);
-	ret = splice_to_pipe(pipe, spd);
-	mutex_lock(&u->iolock);
-
-	return ret;
-}
-
 static int unix_stream_splice_actor(struct sk_buff *skb,
 				    int skip, int chunk,
 				    struct unix_stream_read_state *state)
 {
 	return skb_splice_bits(skb, state->socket->sk,
 			       UNIXCB(skb).consumed + skip,
-			       state->pipe, chunk, state->splice_flags,
+			       state->pipe, chunk, state->splice_flags);
-			       skb_unix_socket_splice);
 }
 
 static ssize_t unix_stream_splice_read(struct socket *sock,  loff_t *ppos,