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io_uring/kbuf: use region api for pbuf rings
Convert internal parts of the provided buffer ring managment to the region API. It's the last non-region mapped ring we have, so it also kills a bunch of now unused memmap.c helpers. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/6c40cf7beaa648558acd4d84bc0fb3279a35d74b.1732886067.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov
Jens Axboe
parent
90175f3f50
commit
ef62de3c4a
4 changed files with 74 additions and 241 deletions
164
io_uring/kbuf.c
164
io_uring/kbuf.c
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@ -351,17 +351,7 @@ static int __io_remove_buffers(struct io_ring_ctx *ctx,
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if (bl->flags & IOBL_BUF_RING) {
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i = bl->buf_ring->tail - bl->head;
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if (bl->buf_nr_pages) {
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int j;
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if (!(bl->flags & IOBL_MMAP)) {
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for (j = 0; j < bl->buf_nr_pages; j++)
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unpin_user_page(bl->buf_pages[j]);
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}
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io_pages_unmap(bl->buf_ring, &bl->buf_pages,
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&bl->buf_nr_pages, bl->flags & IOBL_MMAP);
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bl->flags &= ~IOBL_MMAP;
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}
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io_free_region(ctx, &bl->region);
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/* make sure it's seen as empty */
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INIT_LIST_HEAD(&bl->buf_list);
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bl->flags &= ~IOBL_BUF_RING;
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@ -614,75 +604,14 @@ int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags)
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return IOU_OK;
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}
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static int io_pin_pbuf_ring(struct io_uring_buf_reg *reg,
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struct io_buffer_list *bl)
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{
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struct io_uring_buf_ring *br = NULL;
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struct page **pages;
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int nr_pages, ret;
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pages = io_pin_pages(reg->ring_addr,
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flex_array_size(br, bufs, reg->ring_entries),
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&nr_pages);
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if (IS_ERR(pages))
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return PTR_ERR(pages);
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br = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
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if (!br) {
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ret = -ENOMEM;
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goto error_unpin;
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}
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#ifdef SHM_COLOUR
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/*
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* On platforms that have specific aliasing requirements, SHM_COLOUR
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* is set and we must guarantee that the kernel and user side align
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* nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
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* the application mmap's the provided ring buffer. Fail the request
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* if we, by chance, don't end up with aligned addresses. The app
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* should use IOU_PBUF_RING_MMAP instead, and liburing will handle
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* this transparently.
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*/
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if ((reg->ring_addr | (unsigned long) br) & (SHM_COLOUR - 1)) {
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ret = -EINVAL;
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goto error_unpin;
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}
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#endif
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bl->buf_pages = pages;
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bl->buf_nr_pages = nr_pages;
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bl->buf_ring = br;
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bl->flags |= IOBL_BUF_RING;
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bl->flags &= ~IOBL_MMAP;
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return 0;
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error_unpin:
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unpin_user_pages(pages, nr_pages);
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kvfree(pages);
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vunmap(br);
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return ret;
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}
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static int io_alloc_pbuf_ring(struct io_ring_ctx *ctx,
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struct io_uring_buf_reg *reg,
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struct io_buffer_list *bl)
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{
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size_t ring_size;
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ring_size = reg->ring_entries * sizeof(struct io_uring_buf_ring);
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bl->buf_ring = io_pages_map(&bl->buf_pages, &bl->buf_nr_pages, ring_size);
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if (IS_ERR(bl->buf_ring)) {
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bl->buf_ring = NULL;
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return -ENOMEM;
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}
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bl->flags |= (IOBL_BUF_RING | IOBL_MMAP);
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return 0;
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}
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int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
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{
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struct io_uring_buf_reg reg;
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struct io_buffer_list *bl, *free_bl = NULL;
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struct io_uring_region_desc rd;
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struct io_uring_buf_ring *br;
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unsigned long mmap_offset;
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unsigned long ring_size;
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int ret;
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lockdep_assert_held(&ctx->uring_lock);
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@ -694,19 +623,8 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
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return -EINVAL;
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if (reg.flags & ~(IOU_PBUF_RING_MMAP | IOU_PBUF_RING_INC))
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return -EINVAL;
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if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
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if (!reg.ring_addr)
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return -EFAULT;
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if (reg.ring_addr & ~PAGE_MASK)
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return -EINVAL;
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} else {
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if (reg.ring_addr)
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return -EINVAL;
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}
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if (!is_power_of_2(reg.ring_entries))
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return -EINVAL;
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/* cannot disambiguate full vs empty due to head/tail size */
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if (reg.ring_entries >= 65536)
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return -EINVAL;
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@ -722,21 +640,47 @@ int io_register_pbuf_ring(struct io_ring_ctx *ctx, void __user *arg)
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return -ENOMEM;
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}
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if (!(reg.flags & IOU_PBUF_RING_MMAP))
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ret = io_pin_pbuf_ring(®, bl);
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else
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ret = io_alloc_pbuf_ring(ctx, ®, bl);
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mmap_offset = reg.bgid << IORING_OFF_PBUF_SHIFT;
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ring_size = flex_array_size(br, bufs, reg.ring_entries);
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memset(&rd, 0, sizeof(rd));
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rd.size = PAGE_ALIGN(ring_size);
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if (!(reg.flags & IOU_PBUF_RING_MMAP)) {
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rd.user_addr = reg.ring_addr;
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rd.flags |= IORING_MEM_REGION_TYPE_USER;
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}
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ret = io_create_region_mmap_safe(ctx, &bl->region, &rd, mmap_offset);
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if (ret)
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goto fail;
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br = io_region_get_ptr(&bl->region);
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#ifdef SHM_COLOUR
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/*
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* On platforms that have specific aliasing requirements, SHM_COLOUR
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* is set and we must guarantee that the kernel and user side align
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* nicely. We cannot do that if IOU_PBUF_RING_MMAP isn't set and
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* the application mmap's the provided ring buffer. Fail the request
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* if we, by chance, don't end up with aligned addresses. The app
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* should use IOU_PBUF_RING_MMAP instead, and liburing will handle
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* this transparently.
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*/
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if (!(reg.flags & IOU_PBUF_RING_MMAP) &&
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((reg.ring_addr | (unsigned long)br) & (SHM_COLOUR - 1))) {
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ret = -EINVAL;
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goto fail;
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}
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#endif
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if (!ret) {
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bl->nr_entries = reg.ring_entries;
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bl->mask = reg.ring_entries - 1;
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bl->flags |= IOBL_BUF_RING;
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bl->buf_ring = br;
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if (reg.flags & IOU_PBUF_RING_INC)
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bl->flags |= IOBL_INC;
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io_buffer_add_list(ctx, bl, reg.bgid);
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return 0;
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}
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fail:
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io_free_region(ctx, &bl->region);
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kfree(free_bl);
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return ret;
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}
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@ -794,32 +738,18 @@ int io_register_pbuf_status(struct io_ring_ctx *ctx, void __user *arg)
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return 0;
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}
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struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
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unsigned long bgid)
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struct io_mapped_region *io_pbuf_get_region(struct io_ring_ctx *ctx,
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unsigned int bgid)
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{
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struct io_buffer_list *bl;
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bl = xa_load(&ctx->io_bl_xa, bgid);
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/* must be a mmap'able buffer ring and have pages */
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if (bl && bl->flags & IOBL_MMAP)
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return bl;
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return ERR_PTR(-EINVAL);
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}
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int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct io_ring_ctx *ctx = file->private_data;
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loff_t pgoff = vma->vm_pgoff << PAGE_SHIFT;
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struct io_buffer_list *bl;
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int bgid;
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lockdep_assert_held(&ctx->mmap_lock);
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bgid = (pgoff & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
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bl = io_pbuf_get_bl(ctx, bgid);
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if (IS_ERR(bl))
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return PTR_ERR(bl);
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bl = xa_load(&ctx->io_bl_xa, bgid);
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if (!bl || !(bl->flags & IOBL_BUF_RING))
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return NULL;
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if (WARN_ON_ONCE(!io_region_is_set(&bl->region)))
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return NULL;
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return io_uring_mmap_pages(ctx, vma, bl->buf_pages, bl->buf_nr_pages);
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return &bl->region;
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}
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@ -3,15 +3,13 @@
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#define IOU_KBUF_H
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#include <uapi/linux/io_uring.h>
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#include <linux/io_uring_types.h>
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enum {
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/* ring mapped provided buffers */
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IOBL_BUF_RING = 1,
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/* ring mapped provided buffers, but mmap'ed by application */
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IOBL_MMAP = 2,
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/* buffers are consumed incrementally rather than always fully */
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IOBL_INC = 4,
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IOBL_INC = 2,
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};
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struct io_buffer_list {
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@ -21,11 +19,8 @@ struct io_buffer_list {
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*/
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union {
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struct list_head buf_list;
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struct {
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struct page **buf_pages;
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struct io_uring_buf_ring *buf_ring;
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};
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};
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__u16 bgid;
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/* below is for ring provided buffers */
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@ -35,6 +30,8 @@ struct io_buffer_list {
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__u16 mask;
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__u16 flags;
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struct io_mapped_region region;
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};
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struct io_buffer {
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@ -81,9 +78,8 @@ void __io_put_kbuf(struct io_kiocb *req, int len, unsigned issue_flags);
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bool io_kbuf_recycle_legacy(struct io_kiocb *req, unsigned issue_flags);
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struct io_buffer_list *io_pbuf_get_bl(struct io_ring_ctx *ctx,
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unsigned long bgid);
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int io_pbuf_mmap(struct file *file, struct vm_area_struct *vma);
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struct io_mapped_region *io_pbuf_get_region(struct io_ring_ctx *ctx,
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unsigned int bgid);
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static inline bool io_kbuf_recycle_ring(struct io_kiocb *req)
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{
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@ -36,90 +36,6 @@ static void *io_mem_alloc_compound(struct page **pages, int nr_pages,
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return page_address(page);
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}
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static void *io_mem_alloc_single(struct page **pages, int nr_pages, size_t size,
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gfp_t gfp)
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{
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void *ret;
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int i;
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for (i = 0; i < nr_pages; i++) {
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pages[i] = alloc_page(gfp);
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if (!pages[i])
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goto err;
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}
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ret = vmap(pages, nr_pages, VM_MAP, PAGE_KERNEL);
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if (ret)
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return ret;
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err:
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while (i--)
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put_page(pages[i]);
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return ERR_PTR(-ENOMEM);
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}
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void *io_pages_map(struct page ***out_pages, unsigned short *npages,
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size_t size)
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{
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gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN;
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struct page **pages;
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int nr_pages;
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void *ret;
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nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
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pages = kvmalloc_array(nr_pages, sizeof(struct page *), gfp);
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if (!pages)
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return ERR_PTR(-ENOMEM);
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ret = io_mem_alloc_compound(pages, nr_pages, size, gfp);
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if (!IS_ERR(ret))
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goto done;
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if (nr_pages == 1)
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goto fail;
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ret = io_mem_alloc_single(pages, nr_pages, size, gfp);
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if (!IS_ERR(ret)) {
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done:
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*out_pages = pages;
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*npages = nr_pages;
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return ret;
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}
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fail:
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kvfree(pages);
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*out_pages = NULL;
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*npages = 0;
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return ret;
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}
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void io_pages_unmap(void *ptr, struct page ***pages, unsigned short *npages,
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bool put_pages)
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{
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bool do_vunmap = false;
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if (!ptr)
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return;
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if (put_pages && *npages) {
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struct page **to_free = *pages;
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int i;
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/*
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* Only did vmap for the non-compound multiple page case.
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* For the compound page, we just need to put the head.
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*/
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if (PageCompound(to_free[0]))
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*npages = 1;
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else if (*npages > 1)
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do_vunmap = true;
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for (i = 0; i < *npages; i++)
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put_page(to_free[i]);
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}
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if (do_vunmap)
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vunmap(ptr);
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kvfree(*pages);
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*pages = NULL;
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*npages = 0;
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}
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struct page **io_pin_pages(unsigned long uaddr, unsigned long len, int *npages)
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{
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unsigned long start, end, nr_pages;
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@ -374,16 +290,14 @@ static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff,
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return ERR_PTR(-EFAULT);
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return ctx->sq_sqes;
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case IORING_OFF_PBUF_RING: {
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struct io_buffer_list *bl;
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struct io_mapped_region *region;
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unsigned int bgid;
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void *ptr;
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bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
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bl = io_pbuf_get_bl(ctx, bgid);
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if (IS_ERR(bl))
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return bl;
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ptr = bl->buf_ring;
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return ptr;
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region = io_pbuf_get_region(ctx, bgid);
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if (!region)
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return ERR_PTR(-EINVAL);
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return io_region_validate_mmap(ctx, region);
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}
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case IORING_MAP_OFF_PARAM_REGION:
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return io_region_validate_mmap(ctx, &ctx->param_region);
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@ -392,15 +306,6 @@ static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff,
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return ERR_PTR(-EINVAL);
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}
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int io_uring_mmap_pages(struct io_ring_ctx *ctx, struct vm_area_struct *vma,
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struct page **pages, int npages)
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{
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unsigned long nr_pages = npages;
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vm_flags_set(vma, VM_DONTEXPAND);
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return vm_insert_pages(vma, vma->vm_start, pages, &nr_pages);
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}
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#ifdef CONFIG_MMU
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static int io_region_mmap(struct io_ring_ctx *ctx,
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@ -435,8 +340,17 @@ __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
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return io_region_mmap(ctx, &ctx->ring_region, vma, page_limit);
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case IORING_OFF_SQES:
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return io_region_mmap(ctx, &ctx->sq_region, vma, UINT_MAX);
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case IORING_OFF_PBUF_RING:
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return io_pbuf_mmap(file, vma);
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case IORING_OFF_PBUF_RING: {
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struct io_mapped_region *region;
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unsigned int bgid;
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bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
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region = io_pbuf_get_region(ctx, bgid);
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if (!region)
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return -EINVAL;
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return io_region_mmap(ctx, region, vma, UINT_MAX);
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}
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case IORING_MAP_OFF_PARAM_REGION:
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return io_region_mmap(ctx, &ctx->param_region, vma, UINT_MAX);
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}
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@ -4,13 +4,6 @@
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#define IORING_MAP_OFF_PARAM_REGION 0x20000000ULL
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struct page **io_pin_pages(unsigned long ubuf, unsigned long len, int *npages);
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int io_uring_mmap_pages(struct io_ring_ctx *ctx, struct vm_area_struct *vma,
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struct page **pages, int npages);
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void *io_pages_map(struct page ***out_pages, unsigned short *npages,
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size_t size);
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void io_pages_unmap(void *ptr, struct page ***pages, unsigned short *npages,
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bool put_pages);
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#ifndef CONFIG_MMU
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unsigned int io_uring_nommu_mmap_capabilities(struct file *file);
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