netdev - [PATCH net-next] page_pool: remove spinlock in page_pool_refill_alloc

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Date:   Fri, 7 Jan 2022 17:00:42 +0800
From:   Yunsheng Lin <linyunsheng@...wei.com>
To:     <davem@...emloft.net>, <kuba@...nel.org>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <hawk@...nel.org>, <ilias.apalodimas@...aro.org>
Subject: [PATCH net-next] page_pool: remove spinlock in page_pool_refill_alloc_cache()

As page_pool_refill_alloc_cache() is only called by
__page_pool_get_cached(), which assumes non-concurrent access
as suggested by the comment in __page_pool_get_cached(), and
ptr_ring allows concurrent access between consumer and producer,
so remove the spinlock in page_pool_refill_alloc_cache().

Signed-off-by: Yunsheng Lin <linyunsheng@...wei.com>
---
 net/core/page_pool.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 1a6978427d6c..6efad8b29e9c 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -130,9 +130,6 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
 	pref_nid = numa_mem_id(); /* will be zero like page_to_nid() */
 #endif
 
-	/* Slower-path: Get pages from locked ring queue */
-	spin_lock(&r->consumer_lock);
-
 	/* Refill alloc array, but only if NUMA match */
 	do {
 		page = __ptr_ring_consume(r);
@@ -157,7 +154,6 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
 	if (likely(pool->alloc.count > 0))
 		page = pool->alloc.cache[--pool->alloc.count];
 
-	spin_unlock(&r->consumer_lock);
 	return page;
 }
 
-- 
2.33.0