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Subject[PATCH 1/2] fs/locks: Use allocation rather than the stack in fcntl_getlk()
Date
Struct file_lock is fairly large, so let's save some space on the stack by
using an allocation for struct file_lock in fcntl_getlk(), just as we do
for fcntl_setlk().

Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
---
fs/locks.c | 46 ++++++++++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/fs/locks.c b/fs/locks.c
index afefeb4ad6de..d7daa6c8932f 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2086,14 +2086,17 @@ static void posix_lock_to_flock64(struct flock64 *flock, struct file_lock *fl)
*/
int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
{
- struct file_lock file_lock;
+ struct file_lock *fl;
int error;

+ fl = locks_alloc_lock();
+ if (fl == NULL)
+ return -ENOMEM;
error = -EINVAL;
if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
goto out;

- error = flock_to_posix_lock(filp, &file_lock, flock);
+ error = flock_to_posix_lock(filp, fl, flock);
if (error)
goto out;

@@ -2103,23 +2106,22 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
goto out;

cmd = F_GETLK;
- file_lock.fl_flags |= FL_OFDLCK;
- file_lock.fl_owner = filp;
+ fl->fl_flags |= FL_OFDLCK;
+ fl->fl_owner = filp;
}

- error = vfs_test_lock(filp, &file_lock);
+ error = vfs_test_lock(filp, fl);
if (error)
goto out;

- flock->l_type = file_lock.fl_type;
- if (file_lock.fl_type != F_UNLCK) {
- error = posix_lock_to_flock(flock, &file_lock);
+ flock->l_type = fl->fl_type;
+ if (fl->fl_type != F_UNLCK) {
+ error = posix_lock_to_flock(flock, fl);
if (error)
- goto rel_priv;
+ goto out;
}
-rel_priv:
- locks_release_private(&file_lock);
out:
+ locks_free_lock(fl);
return error;
}

@@ -2298,14 +2300,18 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
*/
int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
{
- struct file_lock file_lock;
+ struct file_lock *fl;
int error;

+ fl = locks_alloc_lock();
+ if (fl == NULL)
+ return -ENOMEM;
+
error = -EINVAL;
if (flock->l_type != F_RDLCK && flock->l_type != F_WRLCK)
goto out;

- error = flock64_to_posix_lock(filp, &file_lock, flock);
+ error = flock64_to_posix_lock(filp, fl, flock);
if (error)
goto out;

@@ -2315,20 +2321,20 @@ int fcntl_getlk64(struct file *filp, unsigned int cmd, struct flock64 *flock)
goto out;

cmd = F_GETLK64;
- file_lock.fl_flags |= FL_OFDLCK;
- file_lock.fl_owner = filp;
+ fl->fl_flags |= FL_OFDLCK;
+ fl->fl_owner = filp;
}

- error = vfs_test_lock(filp, &file_lock);
+ error = vfs_test_lock(filp, fl);
if (error)
goto out;

- flock->l_type = file_lock.fl_type;
- if (file_lock.fl_type != F_UNLCK)
- posix_lock_to_flock64(flock, &file_lock);
+ flock->l_type = fl->fl_type;
+ if (fl->fl_type != F_UNLCK)
+ posix_lock_to_flock64(flock, fl);

- locks_release_private(&file_lock);
out:
+ locks_free_lock(fl);
return error;
}

--
2.9.3
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