netdev - [PATCH] page_pool: fill page only when refill condition is true

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Date:   Wed,  5 Feb 2020 16:22:34 +0800
From:   Li RongQing <lirongqing@...du.com>
To:     netdev@...r.kernel.org, brouer@...hat.com
Subject: [PATCH] page_pool: fill page only when refill condition is true

"do {} while" in page_pool_refill_alloc_cache will always
refill page once whether refill is true or false, and whether
alloc.count of pool is less than PP_ALLOC_CACHE_REFILL.

so fix it by calling page_pool_refill_alloc_cache() only when
refill is true

Fixes: 44768decb7c0 ("page_pool: handle page recycle for NUMA_NO_NODE condition")
Signed-off-by: Li RongQing <lirongqing@...du.com>
Cc: Jesper Dangaard Brouer <brouer@...hat.com>
---
 net/core/page_pool.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 9b7cbe35df37..35ce663cb9de 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -99,8 +99,7 @@ EXPORT_SYMBOL(page_pool_create);
 static void __page_pool_return_page(struct page_pool *pool, struct page *page);
 
 noinline
-static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
-						 bool refill)
+static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
 {
 	struct ptr_ring *r = &pool->ring;
 	struct page *page;
@@ -141,8 +140,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
 			page = NULL;
 			break;
 		}
-	} while (pool->alloc.count < PP_ALLOC_CACHE_REFILL &&
-		 refill);
+	} while (pool->alloc.count < PP_ALLOC_CACHE_REFILL);
 
 	/* Return last page */
 	if (likely(pool->alloc.count > 0))
@@ -156,7 +154,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
 static struct page *__page_pool_get_cached(struct page_pool *pool)
 {
 	bool refill = false;
-	struct page *page;
+	struct page *page = NULL;
 
 	/* Test for safe-context, caller should provide this guarantee */
 	if (likely(in_serving_softirq())) {
@@ -168,7 +166,8 @@ static struct page *__page_pool_get_cached(struct page_pool *pool)
 		refill = true;
 	}
 
-	page = page_pool_refill_alloc_cache(pool, refill);
+	if (refill)
+		page = page_pool_refill_alloc_cache(pool);
 	return page;
 }
 
-- 
2.16.2