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Commit 39005d02 authored by Miklos Szeredi's avatar Miklos Szeredi Committed by Linus Torvalds
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[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: default avatarMiklos Szeredi <miklos@szeredi.hu>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0d9a490a

fs/locks.c

+10 −3
Original line number Diff line number Diff line
@@ -794,7 +794,8 @@ static int flock_lock_file(struct file *filp, struct file_lock *request) 
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) {