[PATCH 1/3] mm/slab: use list_first_entry_or_null()

[Geliang Tang]

Simplify the code with list_first_entry_or_null().

Signed-off-by: Geliang Tang <geliangtang@xxxxxxx>
---
 mm/slab.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/mm/slab.c b/mm/slab.c
index 4765c97..6bb0466 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2791,18 +2791,18 @@ retry:
 	}
 
 	while (batchcount > 0) {
-		struct list_head *entry;
 		struct page *page;
 		/* Get slab alloc is to come from. */
-		entry = n->slabs_partial.next;
-		if (entry == &n->slabs_partial) {
+		page = list_first_entry_or_null(&n->slabs_partial,
+				struct page, lru);
+		if (!page) {
 			n->free_touched = 1;
-			entry = n->slabs_free.next;
-			if (entry == &n->slabs_free)
+			page = list_first_entry_or_null(&n->slabs_free,
+					struct page, lru);
+			if (!page)
 				goto must_grow;
 		}
 
-		page = list_entry(entry, struct page, lru);
 		check_spinlock_acquired(cachep);
 
 		/*
@@ -3085,7 +3085,6 @@ retry:
 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 				int nodeid)
 {
-	struct list_head *entry;
 	struct page *page;
 	struct kmem_cache_node *n;
 	void *obj;
@@ -3098,15 +3097,16 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 retry:
 	check_irq_off();
 	spin_lock(&n->list_lock);
-	entry = n->slabs_partial.next;
-	if (entry == &n->slabs_partial) {
+	page = list_first_entry_or_null(&n->slabs_partial,
+			struct page, lru);
+	if (!page) {
 		n->free_touched = 1;
-		entry = n->slabs_free.next;
-		if (entry == &n->slabs_free)
+		page = list_first_entry_or_null(&n->slabs_free,
+				struct page, lru);
+		if (!page)
 			goto must_grow;
 	}
 
-	page = list_entry(entry, struct page, lru);
 	check_spinlock_acquired_node(cachep, nodeid);
 
 	STATS_INC_NODEALLOCS(cachep);
-- 
2.5.0


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