kill-the-BKL/reiserfs: provide a tool to lock only once the write lock
authorFrederic Weisbecker <fweisbec@gmail.com>
Tue, 14 Apr 2009 03:34:23 +0000 (05:34 +0200)
committerFrederic Weisbecker <fweisbec@gmail.com>
Mon, 14 Sep 2009 05:18:02 +0000 (07:18 +0200)
commitdaf88c898312a22b5385655bc6e0b064eaa2efba
tree016c432fc26c174d5aee3647e54f2aafb690dceb
parenta412f9efdd6424bf4bf28c8e8c92060b5e975482
kill-the-BKL/reiserfs: provide a tool to lock only once the write lock

Sometimes we don't want to recursively hold the per superblock write
lock because we want to be sure it is actually released when we come
to sleep.

This patch introduces the necessary tools for that.

reiserfs_write_lock_once() does the same job than reiserfs_write_lock()
except that it won't try to acquire recursively the lock if the current
task already owns it. Also the lock_depth before the call of this function
is returned.

reiserfs_write_unlock_once() unlock only if reiserfs_write_lock_once()
returned a depth equal to -1, ie: only if it actually locked.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@texware.it>
Cc: Jeff Mahoney <jeffm@suse.com>
Cc: Alexander Beregalov <a.beregalov@gmail.com>
Cc: Chris Mason <chris.mason@oracle.com>
LKML-Reference: <1239680065-25013-2-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fs/reiserfs/lock.c
include/linux/reiserfs_fs.h