X-Git-Url: http://pilppa.org/gitweb/?a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_mru_cache.c;h=a0b2c0a2589a97166f23982999aa3a15b95a9687;hb=77336828c01933d37102c4bef6e2a2cf7e3243b3;hp=7deb9e3cbbd3dcb2669186605f8cb9fc91d084e3;hpb=939ab20152390c8ccccfa6fac0830405ca91d903;p=linux-2.6-omap-h63xx.git

diff --git a/fs/xfs/xfs_mru_cache.c b/fs/xfs/xfs_mru_cache.c
index 7deb9e3cbbd..a0b2c0a2589 100644
--- a/fs/xfs/xfs_mru_cache.c
+++ b/fs/xfs/xfs_mru_cache.c
@@ -206,8 +206,11 @@ _xfs_mru_cache_list_insert(
 	 */
 	if (!_xfs_mru_cache_migrate(mru, now)) {
 		mru->time_zero = now;
-		if (!mru->next_reap)
-			mru->next_reap = mru->grp_count * mru->grp_time;
+		if (!mru->queued) {
+			mru->queued = 1;
+			queue_delayed_work(xfs_mru_reap_wq, &mru->work,
+			                   mru->grp_count * mru->grp_time);
+		}
 	} else {
 		grp = (now - mru->time_zero) / mru->grp_time;
 		grp = (mru->lru_grp + grp) % mru->grp_count;
@@ -222,10 +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;
@@ -242,7 +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) {
 
@@ -256,7 +263,7 @@ _xfs_mru_cache_clear_reap_list(
 		kmem_zone_free(xfs_mru_elem_zone, elem);
 	}
 
-	mutex_spinlock(&mru->lock);
+	spin_lock(&mru->lock);
 }
 
 /*
@@ -271,30 +278,27 @@ _xfs_mru_cache_reap(
 	struct work_struct	*work)
 {
 	xfs_mru_cache_t		*mru = container_of(work, xfs_mru_cache_t, work.work);
-	unsigned long		now;
+	unsigned long		now, next;
 
 	ASSERT(mru && mru->lists);
 	if (!mru || !mru->lists)
 		return;
 
-	mutex_spinlock(&mru->lock);
-	now = jiffies;
-	if (mru->reap_all ||
-	    (mru->next_reap && time_after(now, mru->next_reap))) {
-		if (mru->reap_all)
-			now += mru->grp_count * mru->grp_time * 2;
-		mru->next_reap = _xfs_mru_cache_migrate(mru, now);
-		_xfs_mru_cache_clear_reap_list(mru);
+	spin_lock(&mru->lock);
+	next = _xfs_mru_cache_migrate(mru, jiffies);
+	_xfs_mru_cache_clear_reap_list(mru);
+
+	mru->queued = next;
+	if ((mru->queued > 0)) {
+		now = jiffies;
+		if (next <= now)
+			next = 0;
+		else
+			next -= now;
+		queue_delayed_work(xfs_mru_reap_wq, &mru->work, next);
 	}
 
-	/*
-	 * the process that triggered the reap_all is responsible
-	 * for restating the periodic reap if it is required.
-	 */
-	if (!mru->reap_all)
-		queue_delayed_work(xfs_mru_reap_wq, &mru->work, mru->grp_time);
-	mru->reap_all = 0;
-	mutex_spinunlock(&mru->lock, 0);
+	spin_unlock(&mru->lock);
 }
 
 int
@@ -352,7 +356,7 @@ xfs_mru_cache_create(
 
 	/* An extra list is needed to avoid reaping up to a grp_time early. */
 	mru->grp_count = grp_count + 1;
-	mru->lists = kmem_alloc(mru->grp_count * sizeof(*mru->lists), KM_SLEEP);
+	mru->lists = kmem_zalloc(mru->grp_count * sizeof(*mru->lists), KM_SLEEP);
 
 	if (!mru->lists) {
 		err = ENOMEM;
@@ -368,17 +372,12 @@ 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;
 	mru->free_func = free_func;
 
-	/* start up the reaper event */
-	mru->next_reap = 0;
-	mru->reap_all = 0;
-	queue_delayed_work(xfs_mru_reap_wq, &mru->work, mru->grp_time);
-
 	*mrup = mru;
 
 exit:
@@ -394,36 +393,26 @@ exit:
  * Call xfs_mru_cache_flush() to flush out all cached entries, calling their
  * free functions as they're deleted.  When this function returns, the caller is
  * guaranteed that all the free functions for all the elements have finished
- * executing.
- *
- * While we are flushing, we stop the periodic reaper event from triggering.
- * Normally, we want to restart this periodic event, but if we are shutting
- * down the cache we do not want it restarted. hence the restart parameter
- * where 0 = do not restart reaper and 1 = restart reaper.
+ * executing and the reaper is not running.
  */
 void
 xfs_mru_cache_flush(
-	xfs_mru_cache_t		*mru,
-	int			restart)
+	xfs_mru_cache_t		*mru)
 {
 	if (!mru || !mru->lists)
 		return;
 
-	cancel_rearming_delayed_workqueue(xfs_mru_reap_wq, &mru->work);
-
-	mutex_spinlock(&mru->lock);
-	mru->reap_all = 1;
-	mutex_spinunlock(&mru->lock, 0);
+	spin_lock(&mru->lock);
+	if (mru->queued) {
+		spin_unlock(&mru->lock);
+		cancel_rearming_delayed_workqueue(xfs_mru_reap_wq, &mru->work);
+		spin_lock(&mru->lock);
+	}
 
-	queue_work(xfs_mru_reap_wq, &mru->work.work);
-	flush_workqueue(xfs_mru_reap_wq);
+	_xfs_mru_cache_migrate(mru, jiffies + mru->grp_count * mru->grp_time);
+	_xfs_mru_cache_clear_reap_list(mru);
 
-	mutex_spinlock(&mru->lock);
-	WARN_ON_ONCE(mru->reap_all != 0);
-	mru->reap_all = 0;
-	if (restart)
-		queue_delayed_work(xfs_mru_reap_wq, &mru->work, mru->grp_time);
-	mutex_spinunlock(&mru->lock, 0);
+	spin_unlock(&mru->lock);
 }
 
 void
@@ -433,8 +422,7 @@ xfs_mru_cache_destroy(
 	if (!mru || !mru->lists)
 		return;
 
-	/* we don't want the reaper to restart here */
-	xfs_mru_cache_flush(mru, 0);
+	xfs_mru_cache_flush(mru);
 
 	kmem_free(mru->lists, mru->grp_count * sizeof(*mru->lists));
 	kmem_free(mru, sizeof(*mru));
@@ -470,13 +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;
 }
@@ -499,14 +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);
@@ -544,6 +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(
@@ -556,14 +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;
 }
@@ -587,10 +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;
 }
@@ -602,7 +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);
 }