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@xxxxxxxxxx>
Index: linux/fs/locks.c
===================================================================
--- linux.orig/fs/locks.c 2006-03-31 18:55:33.000000000 +0200
+++ linux/fs/locks.c 2006-03-31 18:55:33.000000000 +0200
@@ -795,7 +795,8 @@ int __posix_lock_file(struct inode *inod
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;
@@ -804,9 +805,15 @@ int __posix_lock_file(struct inode *inod
/*
* 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) {
-
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