1 files changed, 38 insertions, 15 deletions

diff --git a/mm/z3fold.c b/mm/z3fold.c
index f579ad4a8100..4b366d181f35 100644
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -144,7 +144,8 @@ enum z3fold_page_flags {
 	PAGE_HEADLESS = 0,
 	MIDDLE_CHUNK_MAPPED,
 	NEEDS_COMPACTING,
-	PAGE_STALE
+	PAGE_STALE,
+	UNDER_RECLAIM
 };
 
 /*****************
@@ -173,6 +174,7 @@ static struct z3fold_header *init_z3fold_page(struct page *page,
 	clear_bit(MIDDLE_CHUNK_MAPPED, &page->private);
 	clear_bit(NEEDS_COMPACTING, &page->private);
 	clear_bit(PAGE_STALE, &page->private);
+	clear_bit(UNDER_RECLAIM, &page->private);
 
 	spin_lock_init(&zhdr->page_lock);
 	kref_init(&zhdr->refcount);
@@ -467,6 +469,8 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
 	spin_lock_init(&pool->lock);
 	spin_lock_init(&pool->stale_lock);
 	pool->unbuddied = __alloc_percpu(sizeof(struct list_head)*NCHUNKS, 2);
+	if (!pool->unbuddied)
+		goto out_pool;
 	for_each_possible_cpu(cpu) {
 		struct list_head *unbuddied =
 				per_cpu_ptr(pool->unbuddied, cpu);
@@ -479,7 +483,7 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
 	pool->name = name;
 	pool->compact_wq = create_singlethread_workqueue(pool->name);
 	if (!pool->compact_wq)
-		goto out;
+		goto out_unbuddied;
 	pool->release_wq = create_singlethread_workqueue(pool->name);
 	if (!pool->release_wq)
 		goto out_wq;
@@ -489,8 +493,11 @@ static struct z3fold_pool *z3fold_create_pool(const char *name, gfp_t gfp,
 
 out_wq:
 	destroy_workqueue(pool->compact_wq);
-out:
+out_unbuddied:
+	free_percpu(pool->unbuddied);
+out_pool:
 	kfree(pool);
+out:
 	return NULL;
 }
 
@@ -533,7 +540,7 @@ static int z3fold_alloc(struct z3fold_pool *pool, size_t size, gfp_t gfp,
 	struct z3fold_header *zhdr = NULL;
 	struct page *page = NULL;
 	enum buddy bud;
-	bool can_sleep = (gfp & __GFP_RECLAIM) == __GFP_RECLAIM;
+	bool can_sleep = gfpflags_allow_blocking(gfp);
 
 	if (!size || (gfp & __GFP_HIGHMEM))
 		return -EINVAL;
@@ -751,6 +758,10 @@ static void z3fold_free(struct z3fold_pool *pool, unsigned long handle)
 		atomic64_dec(&pool->pages_nr);
 		return;
 	}
+	if (test_bit(UNDER_RECLAIM, &page->private)) {
+		z3fold_page_unlock(zhdr);
+		return;
+	}
 	if (test_and_set_bit(NEEDS_COMPACTING, &page->private)) {
 		z3fold_page_unlock(zhdr);
 		return;
@@ -835,6 +846,8 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
 			kref_get(&zhdr->refcount);
 			list_del_init(&zhdr->buddy);
 			zhdr->cpu = -1;
+			set_bit(UNDER_RECLAIM, &page->private);
+			break;
 		}
 
 		list_del_init(&page->lru);
@@ -882,25 +895,35 @@ static int z3fold_reclaim_page(struct z3fold_pool *pool, unsigned int retries)
 				goto next;
 		}
 next:
-		spin_lock(&pool->lock);
 		if (test_bit(PAGE_HEADLESS, &page->private)) {
 			if (ret == 0) {
-				spin_unlock(&pool->lock);
 				free_z3fold_page(page);
 				return 0;
 			}
-		} else if (kref_put(&zhdr->refcount, release_z3fold_page)) {
-			atomic64_dec(&pool->pages_nr);
+			spin_lock(&pool->lock);
+			list_add(&page->lru, &pool->lru);
 			spin_unlock(&pool->lock);
-			return 0;
+		} else {
+			z3fold_page_lock(zhdr);
+			clear_bit(UNDER_RECLAIM, &page->private);
+			if (kref_put(&zhdr->refcount,
+					release_z3fold_page_locked)) {
+				atomic64_dec(&pool->pages_nr);
+				return 0;
+			}
+			/*
+			 * if we are here, the page is still not completely
+			 * free. Take the global pool lock then to be able
+			 * to add it back to the lru list
+			 */
+			spin_lock(&pool->lock);
+			list_add(&page->lru, &pool->lru);
+			spin_unlock(&pool->lock);
+			z3fold_page_unlock(zhdr);
 		}
 
-		/*
-		 * Add to the beginning of LRU.
-		 * Pool lock has to be kept here to ensure the page has
-		 * not already been released
-		 */
-		list_add(&page->lru, &pool->lru);
+		/* We started off locked to we need to lock the pool back */
+		spin_lock(&pool->lock);
 	}
 	spin_unlock(&pool->lock);
 	return -EAGAIN;