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fs/lock: Don't allocate file_lock in flock_make_lock().

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Two functions, flock syscall and locks_remove_flock(), call
flock_make_lock().  It allocates struct file_lock from slab
cache if its argument fl is NULL.

When we call flock syscall, we pass NULL to allocate memory
for struct file_lock.  However, we always free it at the end
by locks_free_lock().  We need not allocate it and instead
should use a local variable as locks_remove_flock() does.

Also, the validation for flock_translate_cmd() is not necessary
for locks_remove_flock().  So we move the part to flock syscall
and make flock_make_lock() return nothing.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-16 21:35:31 -07:00 committed by Jeff Layton
parent ff6992735a
commit 4149be7bda
1 changed files with 16 additions and 32 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

48
fs/locks.c
View file

@ -425,21 +425,9 @@ static inline int flock_translate_cmd(int cmd) {
}
/* Fill in a file_lock structure with an appropriate FLOCK lock. */
static struct file_lock *
flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
static void flock_make_lock(struct file *filp, struct file_lock *fl, int type)
{
int type = flock_translate_cmd(cmd);
if (type < 0)
return ERR_PTR(type);
if (fl == NULL) {
fl = locks_alloc_lock();
if (fl == NULL)
return ERR_PTR(-ENOMEM);
} else {
locks_init_lock(fl);
}
locks_init_lock(fl);
fl->fl_file = filp;
fl->fl_owner = filp;
@ -447,8 +435,6 @@ flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
fl->fl_flags = FL_FLOCK;
fl->fl_type = type;
fl->fl_end = OFFSET_MAX;
return fl;
}
static int assign_type(struct file_lock *fl, long type)
@ -2097,10 +2083,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait);
*/
SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
int can_sleep, error, unlock, type;
struct fd f = fdget(fd);
struct file_lock *lock;
int can_sleep, unlock;
int error;
struct file_lock fl;
error = -EBADF;
if (!f.file)
@ -2127,28 +2112,27 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
goto out_putf;
}
lock = flock_make_lock(f.file, cmd, NULL);
if (IS_ERR(lock)) {
error = PTR_ERR(lock);
type = flock_translate_cmd(cmd);
if (type < 0) {
error = type;
goto out_putf;
}
if (can_sleep)
lock->fl_flags |= FL_SLEEP;
flock_make_lock(f.file, &fl, type);
error = security_file_lock(f.file, lock->fl_type);
if (can_sleep)
fl.fl_flags |= FL_SLEEP;
error = security_file_lock(f.file, fl.fl_type);
if (error)
goto out_free;
goto out_putf;
if (f.file->f_op->flock)
error = f.file->f_op->flock(f.file,
(can_sleep) ? F_SETLKW : F_SETLK,
lock);
&fl);
else
error = locks_lock_file_wait(f.file, lock);
out_free:
locks_free_lock(lock);
error = locks_lock_file_wait(f.file, &fl);
out_putf:
fdput(f);
@ -2614,7 +2598,7 @@ locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
if (list_empty(&flctx->flc_flock))
return;
flock_make_lock(filp, LOCK_UN, &fl);
flock_make_lock(filp, &fl, F_UNLCK);
fl.fl_flags |= FL_CLOSE;
if (filp->f_op->flock)