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authorLi RongQing <lirongqing@baidu.com>2020-02-11 10:13:44 +0800
committerDavid S. Miller <davem@davemloft.net>2020-02-13 14:11:51 -0800
commit304db6cb7610eb9104e1f911b235d87dc4802558 (patch)
tree9342e9b242f6feef581c57d1e931d65ad5abbc5a /net
parent89e960b5a99511f21d07da50eb34aeeb46cfba0f (diff)
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page_pool: refill page when alloc.count of pool is zero
"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 or not this is wrong, and will cause overflow of pool->alloc.cache the caller of __page_pool_get_cached should provide guarantee that pool->alloc.cache is safe to access, so in_serving_softirq should be removed as suggested by Jesper Dangaard Brouer in https://patchwork.ozlabs.org/patch/1233713/ so fix this issue by calling page_pool_refill_alloc_cache() only when pool->alloc.count is zero Fixes: 44768decb7c0 ("page_pool: handle page recycle for NUMA_NO_NODE condition") Signed-off-by: Li RongQing <lirongqing@baidu.com> Suggested-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/page_pool.c22
1 files changed, 8 insertions, 14 deletions
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 9b7cbe35df37..10d2b255df5e 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))
@@ -155,20 +153,16 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
/* fast path */
static struct page *__page_pool_get_cached(struct page_pool *pool)
{
- bool refill = false;
struct page *page;
- /* Test for safe-context, caller should provide this guarantee */
- if (likely(in_serving_softirq())) {
- if (likely(pool->alloc.count)) {
- /* Fast-path */
- page = pool->alloc.cache[--pool->alloc.count];
- return page;
- }
- refill = true;
+ /* Caller MUST guarantee safe non-concurrent access, e.g. softirq */
+ if (likely(pool->alloc.count)) {
+ /* Fast-path */
+ page = pool->alloc.cache[--pool->alloc.count];
+ } else {
+ page = page_pool_refill_alloc_cache(pool);
}
- page = page_pool_refill_alloc_cache(pool, refill);
return page;
}