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authorMiklos Szeredi <miklos@szeredi.hu>2006-06-23 13:05:10 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-23 18:43:02 +0400
commit39005d022ad221b76dc2de0ac62ef475a796433b (patch)
treee0a36fec7076d48764f0588b9ce09ce8e9f067ff /fs/locks.c
parent0d9a490abe1f69fda220f7866f6f23af41daa128 (diff)
downloadlinux-39005d022ad221b76dc2de0ac62ef475a796433b.tar.xz
[PATCH] locks: don't do unnecessary allocations
posix_lock_file() always allocates new locks in advance, even if it's easy to determine that no allocations will be needed. Optimize these cases: - FL_ACCESS flag is set - Unlocking the whole range Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/locks.c')
-rw-r--r--fs/locks.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/locks.c b/fs/locks.c
index c5ac6b40e766..2344f241c687 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -794,7 +794,8 @@ out:
static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
{
struct file_lock *fl;
- struct file_lock *new_fl, *new_fl2;
+ struct file_lock *new_fl = NULL;
+ struct file_lock *new_fl2 = NULL;
struct file_lock *left = NULL;
struct file_lock *right = NULL;
struct file_lock **before;
@@ -803,9 +804,15 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
/*
* We may need two file_lock structures for this operation,
* so we get them in advance to avoid races.
+ *
+ * In some cases we can be sure, that no new locks will be needed
*/
- new_fl = locks_alloc_lock();
- new_fl2 = locks_alloc_lock();
+ if (!(request->fl_flags & FL_ACCESS) &&
+ (request->fl_type != F_UNLCK ||
+ request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
+ new_fl = locks_alloc_lock();
+ new_fl2 = locks_alloc_lock();
+ }
lock_kernel();
if (request->fl_type != F_UNLCK) {