Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6

* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6: (23 commits)
  [PATCH] sysfs: fix a kobject leak in sysfs_add_link on the error path
  [PATCH] sysfs: don't export dir symbols
  [PATCH] get_cpu_sysdev() signedness fix
  [PATCH] kobject_add_dir
  [PATCH] debugfs: Add debugfs_create_blob() helper for exporting binary data
  [PATCH] sysfs: fix problem with duplicate sysfs directories and files
  [PATCH] Kobject: kobject.h: fix a typo
  [PATCH] Kobject: provide better warning messages when people do stupid things
  [PATCH] Driver core: add macros notice(), dev_notice()
  [PATCH] firmware: fix BUG: in fw_realloc_buffer
  [PATCH] sysfs: kzalloc conversion
  [PATCH] fix module sysfs files reference counting
  [PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to USB subsystem
  [PATCH] add EXPORT_SYMBOL_GPL_FUTURE() to RCU subsystem
  [PATCH] add EXPORT_SYMBOL_GPL_FUTURE()
  [PATCH] Clean up module.c symbol searching logic
  [PATCH] kobj_map semaphore to mutex conversion
  [PATCH] kref: avoid an atomic operation in kref_put()
  [PATCH] handle errors returned by platform_get_irq*()
  [PATCH] driver core: platform_get_irq*(): return -ENXIO on error
  ...

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/kref.c b/lib/kref.c
index 0d07cc31c818..4a467faf1367 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -52,7 +52,12 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
         WARN_ON(release == NULL);
         WARN_ON(release == (void (*)(struct kref *))kfree);
 
-        if (atomic_dec_and_test(&kref->refcount)) {
+        /*
+         * if current count is one, we are the last user and can release object
+         * right now, avoiding an atomic operation on 'refcount'
+         */
+        if ((atomic_read(&kref->refcount) == 1) ||
+            (atomic_dec_and_test(&kref->refcount))) {
                 release(kref);
                 return 1;
         }