- Update to 2.6.25-rc3.

[linux-flexiantxendom0-3.2.10.git] / fs / xfs / xfs_mru_cache.c

diff --git a/fs/xfs/xfs_mru_cache.c b/fs/xfs/xfs_mru_cache.c
index e0b358c..a0b2c0a 100644 (file)
--- a/fs/xfs/xfs_mru_cache.c
+++ b/fs/xfs/xfs_mru_cache.c
@@ -225,10 +225,14 @@ _xfs_mru_cache_list_insert(
  * list need to be deleted.  For each element this involves removing it from the
  * data store, removing it from the reap list, calling the client's free
  * function and deleting the element from the element zone.
+ *
+ * We get called holding the mru->lock, which we drop and then reacquire.
+ * Sparse need special help with this to tell it we know what we are doing.
  */
 STATIC void
 _xfs_mru_cache_clear_reap_list(
-       xfs_mru_cache_t         *mru)
+       xfs_mru_cache_t         *mru) __releases(mru->lock) __acquires(mru->lock)
+
 {
        xfs_mru_cache_elem_t    *elem, *next;
        struct list_head        tmp;
@@ -245,7 +249,7 @@ _xfs_mru_cache_clear_reap_list(
                 */
                list_move(&elem->list_node, &tmp);
        }
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 
        list_for_each_entry_safe(elem, next, &tmp, list_node) {
 
@@ -259,7 +263,7 @@ _xfs_mru_cache_clear_reap_list(
                kmem_zone_free(xfs_mru_elem_zone, elem);
        }
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
 }
 
 /*
@@ -280,7 +284,7 @@ _xfs_mru_cache_reap(
        if (!mru || !mru->lists)
                return;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
        next = _xfs_mru_cache_migrate(mru, jiffies);
        _xfs_mru_cache_clear_reap_list(mru);
 
@@ -294,7 +298,7 @@ _xfs_mru_cache_reap(
                queue_delayed_work(xfs_mru_reap_wq, &mru->work, next);
        }
 
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 }
 
 int
@@ -368,7 +372,7 @@ xfs_mru_cache_create(
         */
        INIT_RADIX_TREE(&mru->store, GFP_ATOMIC);
        INIT_LIST_HEAD(&mru->reap_list);
-       spinlock_init(&mru->lock, "xfs_mru_cache");
+       spin_lock_init(&mru->lock);
        INIT_DELAYED_WORK(&mru->work, _xfs_mru_cache_reap);
 
        mru->grp_time  = grp_time;
@@ -398,17 +402,17 @@ xfs_mru_cache_flush(
        if (!mru || !mru->lists)
                return;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
        if (mru->queued) {
-               mutex_spinunlock(&mru->lock, 0);
+               spin_unlock(&mru->lock);
                cancel_rearming_delayed_workqueue(xfs_mru_reap_wq, &mru->work);
-               mutex_spinlock(&mru->lock);
+               spin_lock(&mru->lock);
        }
 
        _xfs_mru_cache_migrate(mru, jiffies + mru->grp_count * mru->grp_time);
        _xfs_mru_cache_clear_reap_list(mru);
 
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 }
 
 void
@@ -454,13 +458,13 @@ xfs_mru_cache_insert(
        elem->key = key;
        elem->value = value;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
 
        radix_tree_insert(&mru->store, key, elem);
        radix_tree_preload_end();
        _xfs_mru_cache_list_insert(mru, elem);
 
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 
        return 0;
 }
@@ -483,14 +487,14 @@ xfs_mru_cache_remove(
        if (!mru || !mru->lists)
                return NULL;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
        elem = radix_tree_delete(&mru->store, key);
        if (elem) {
                value = elem->value;
                list_del(&elem->list_node);
        }
 
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 
        if (elem)
                kmem_zone_free(xfs_mru_elem_zone, elem);
@@ -528,6 +532,10 @@ xfs_mru_cache_delete(
  *
  * If the element isn't found, this function returns NULL and the spinlock is
  * released.  xfs_mru_cache_done() should NOT be called when this occurs.
+ *
+ * Because sparse isn't smart enough to know about conditional lock return
+ * status, we need to help it get it right by annotating the path that does
+ * not release the lock.
  */
 void *
 xfs_mru_cache_lookup(
@@ -540,14 +548,14 @@ xfs_mru_cache_lookup(
        if (!mru || !mru->lists)
                return NULL;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
        elem = radix_tree_lookup(&mru->store, key);
        if (elem) {
                list_del(&elem->list_node);
                _xfs_mru_cache_list_insert(mru, elem);
-       }
-       else
-               mutex_spinunlock(&mru->lock, 0);
+               __release(mru_lock); /* help sparse not be stupid */
+       } else
+               spin_unlock(&mru->lock);
 
        return elem ? elem->value : NULL;
 }
@@ -571,10 +579,12 @@ xfs_mru_cache_peek(
        if (!mru || !mru->lists)
                return NULL;
 
-       mutex_spinlock(&mru->lock);
+       spin_lock(&mru->lock);
        elem = radix_tree_lookup(&mru->store, key);
        if (!elem)
-               mutex_spinunlock(&mru->lock, 0);
+               spin_unlock(&mru->lock);
+       else
+               __release(mru_lock); /* help sparse not be stupid */
 
        return elem ? elem->value : NULL;
 }
@@ -586,7 +596,7 @@ xfs_mru_cache_peek(
  */
 void
 xfs_mru_cache_done(
-       xfs_mru_cache_t *mru)
+       xfs_mru_cache_t *mru) __releases(mru->lock)
 {
-       mutex_spinunlock(&mru->lock, 0);
+       spin_unlock(&mru->lock);
 }