Merge tag 'for-v4.6-rc/omap-fixes-a' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v4.6/fixes

ARM: OMAP2+: first hwmod fix for v4.6-rc

Fix a longstanding bug in the hwmod code that could cause
hardware SYSCONFIG register values to not match the kernel's
idea of what they should be, and that could result in lower
performance during IP block idle entry.

Basic build, boot, and PM test logs are available here:

http://www.pwsan.com/omap/testlogs/omap-hwmod-fixes-a-for-v4.6-rc/20160326231727/

1 files changed, 24 insertions, 12 deletions

diff --git a/mm/mempool.c b/mm/mempool.c
index 004d42b1dfaf..9b7a14a791cc 100644
--- a/mm/mempool.c
+++ b/mm/mempool.c
@@ -112,12 +112,12 @@ static void kasan_poison_element(mempool_t *pool, void *element)
 		kasan_free_pages(element, (unsigned long)pool->pool_data);
 }
 
-static void kasan_unpoison_element(mempool_t *pool, void *element)
+static void kasan_unpoison_element(mempool_t *pool, void *element, gfp_t flags)
 {
 	if (pool->alloc == mempool_alloc_slab)
-		kasan_slab_alloc(pool->pool_data, element);
+		kasan_slab_alloc(pool->pool_data, element, flags);
 	if (pool->alloc == mempool_kmalloc)
-		kasan_krealloc(element, (size_t)pool->pool_data);
+		kasan_krealloc(element, (size_t)pool->pool_data, flags);
 	if (pool->alloc == mempool_alloc_pages)
 		kasan_alloc_pages(element, (unsigned long)pool->pool_data);
 }
@@ -130,13 +130,13 @@ static void add_element(mempool_t *pool, void *element)
 	pool->elements[pool->curr_nr++] = element;
 }
 
-static void *remove_element(mempool_t *pool)
+static void *remove_element(mempool_t *pool, gfp_t flags)
 {
 	void *element = pool->elements[--pool->curr_nr];
 
 	BUG_ON(pool->curr_nr < 0);
+	kasan_unpoison_element(pool, element, flags);
 	check_element(pool, element);
-	kasan_unpoison_element(pool, element);
 	return element;
 }
 
@@ -154,7 +154,7 @@ void mempool_destroy(mempool_t *pool)
 		return;
 
 	while (pool->curr_nr) {
-		void *element = remove_element(pool);
+		void *element = remove_element(pool, GFP_KERNEL);
 		pool->free(element, pool->pool_data);
 	}
 	kfree(pool->elements);
@@ -250,7 +250,7 @@ int mempool_resize(mempool_t *pool, int new_min_nr)
 	spin_lock_irqsave(&pool->lock, flags);
 	if (new_min_nr <= pool->min_nr) {
 		while (new_min_nr < pool->curr_nr) {
-			element = remove_element(pool);
+			element = remove_element(pool, GFP_KERNEL);
 			spin_unlock_irqrestore(&pool->lock, flags);
 			pool->free(element, pool->pool_data);
 			spin_lock_irqsave(&pool->lock, flags);
@@ -310,25 +310,36 @@ EXPORT_SYMBOL(mempool_resize);
  * returns NULL. Note that due to preallocation, this function
  * *never* fails when called from process contexts. (it might
  * fail if called from an IRQ context.)
- * Note: using __GFP_ZERO is not supported.
+ * Note: neither __GFP_NOMEMALLOC nor __GFP_ZERO are supported.
  */
-void * mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
+void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask)
 {
 	void *element;
 	unsigned long flags;
 	wait_queue_t wait;
 	gfp_t gfp_temp;
 
+	/* If oom killed, memory reserves are essential to prevent livelock */
+	VM_WARN_ON_ONCE(gfp_mask & __GFP_NOMEMALLOC);
+	/* No element size to zero on allocation */
 	VM_WARN_ON_ONCE(gfp_mask & __GFP_ZERO);
+
 	might_sleep_if(gfp_mask & __GFP_DIRECT_RECLAIM);
 
-	gfp_mask |= __GFP_NOMEMALLOC;	/* don't allocate emergency reserves */
 	gfp_mask |= __GFP_NORETRY;	/* don't loop in __alloc_pages */
 	gfp_mask |= __GFP_NOWARN;	/* failures are OK */
 
 	gfp_temp = gfp_mask & ~(__GFP_DIRECT_RECLAIM|__GFP_IO);
 
 repeat_alloc:
+	if (likely(pool->curr_nr)) {
+		/*
+		 * Don't allocate from emergency reserves if there are
+		 * elements available.  This check is racy, but it will
+		 * be rechecked each loop.
+		 */
+		gfp_temp |= __GFP_NOMEMALLOC;
+	}
 
 	element = pool->alloc(gfp_temp, pool->pool_data);
 	if (likely(element != NULL))
@@ -336,7 +347,7 @@ repeat_alloc:
 
 	spin_lock_irqsave(&pool->lock, flags);
 	if (likely(pool->curr_nr)) {
-		element = remove_element(pool);
+		element = remove_element(pool, gfp_temp);
 		spin_unlock_irqrestore(&pool->lock, flags);
 		/* paired with rmb in mempool_free(), read comment there */
 		smp_wmb();
@@ -352,11 +363,12 @@ repeat_alloc:
 	 * We use gfp mask w/o direct reclaim or IO for the first round.  If
 	 * alloc failed with that and @pool was empty, retry immediately.
 	 */
-	if (gfp_temp != gfp_mask) {
+	if ((gfp_temp & ~__GFP_NOMEMALLOC) != gfp_mask) {
 		spin_unlock_irqrestore(&pool->lock, flags);
 		gfp_temp = gfp_mask;
 		goto repeat_alloc;
 	}
+	gfp_temp = gfp_mask;
 
 	/* We must not sleep if !__GFP_DIRECT_RECLAIM */
 	if (!(gfp_mask & __GFP_DIRECT_RECLAIM)) {