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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-12 13:00:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-12 13:00:44 -0700
commit4ac1800f81eb52f776aca201e791eec2ef355259 (patch)
tree032e7be62091aa106e83307c805d1180db57ebd8 /lib
parenta1bf4c7da62fcadea065f7c9a561d61c26ea4882 (diff)
parent3e7aafc39c59c639ebd5961f893743f076df9b4e (diff)
downloadlinux-4ac1800f81eb52f776aca201e791eec2ef355259.tar.bz2
Merge tag 'gfs2-4.17.fixes2' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull more gfs2 updates from Bob Peterson: "We decided to request the latest three patches to be merged into this merge window while it's still open. - The first patch adds a new function to lockref: lockref_put_not_zero - The second patch fixes GFS2's glock dump code so it uses the new lockref function. This fixes a problem whereby lock dumps could miss glocks. - I made a minor patch to update some comments and fix the lock ordering text in our gfs2-glocks.txt Documentation file" * tag 'gfs2-4.17.fixes2' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: GFS2: Minor improvements to comments and documentation gfs2: Stop using rhashtable_walk_peek lockref: Add lockref_put_not_zero
Diffstat (limited to 'lib')
-rw-r--r--lib/lockref.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/lockref.c b/lib/lockref.c
index 47169ed7e964..3d468b53d4c9 100644
--- a/lib/lockref.c
+++ b/lib/lockref.c
@@ -81,6 +81,34 @@ int lockref_get_not_zero(struct lockref *lockref)
EXPORT_SYMBOL(lockref_get_not_zero);
/**
+ * lockref_put_not_zero - Decrements count unless count <= 1 before decrement
+ * @lockref: pointer to lockref structure
+ * Return: 1 if count updated successfully or 0 if count would become zero
+ */
+int lockref_put_not_zero(struct lockref *lockref)
+{
+ int retval;
+
+ CMPXCHG_LOOP(
+ new.count--;
+ if (old.count <= 1)
+ return 0;
+ ,
+ return 1;
+ );
+
+ spin_lock(&lockref->lock);
+ retval = 0;
+ if (lockref->count > 1) {
+ lockref->count--;
+ retval = 1;
+ }
+ spin_unlock(&lockref->lock);
+ return retval;
+}
+EXPORT_SYMBOL(lockref_put_not_zero);
+
+/**
* lockref_get_or_lock - Increments count unless the count is 0 or dead
* @lockref: pointer to lockref structure
* Return: 1 if count updated successfully or 0 if count was zero