[PATCH] locks: don't do unnecessary allocations (39005d02) · Commits · 戴 / test

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>

fs/locks.c

+10 −3

Original line number	Diff line number	Diff line
		@@ -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
		*/
		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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