Commit 304db6cb authored by Li RongQing's avatar Li RongQing Committed by David S. Miller

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: 44768dec ("page_pool: handle page recycle for NUMA_NO_NODE condition")
Signed-off-by: default avatarLi RongQing <lirongqing@baidu.com>
Suggested-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: default avatarIlias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 89e960b5
...@@ -99,8 +99,7 @@ EXPORT_SYMBOL(page_pool_create); ...@@ -99,8 +99,7 @@ EXPORT_SYMBOL(page_pool_create);
static void __page_pool_return_page(struct page_pool *pool, struct page *page); static void __page_pool_return_page(struct page_pool *pool, struct page *page);
noinline noinline
static struct page *page_pool_refill_alloc_cache(struct page_pool *pool, static struct page *page_pool_refill_alloc_cache(struct page_pool *pool)
bool refill)
{ {
struct ptr_ring *r = &pool->ring; struct ptr_ring *r = &pool->ring;
struct page *page; struct page *page;
...@@ -141,8 +140,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool, ...@@ -141,8 +140,7 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
page = NULL; page = NULL;
break; break;
} }
} while (pool->alloc.count < PP_ALLOC_CACHE_REFILL && } while (pool->alloc.count < PP_ALLOC_CACHE_REFILL);
refill);
/* Return last page */ /* Return last page */
if (likely(pool->alloc.count > 0)) if (likely(pool->alloc.count > 0))
...@@ -155,20 +153,16 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool, ...@@ -155,20 +153,16 @@ static struct page *page_pool_refill_alloc_cache(struct page_pool *pool,
/* fast path */ /* fast path */
static struct page *__page_pool_get_cached(struct page_pool *pool) static struct page *__page_pool_get_cached(struct page_pool *pool)
{ {
bool refill = false;
struct page *page; struct page *page;
/* Test for safe-context, caller should provide this guarantee */ /* Caller MUST guarantee safe non-concurrent access, e.g. softirq */
if (likely(in_serving_softirq())) {
if (likely(pool->alloc.count)) { if (likely(pool->alloc.count)) {
/* Fast-path */ /* Fast-path */
page = pool->alloc.cache[--pool->alloc.count]; page = pool->alloc.cache[--pool->alloc.count];
return page; } else {
} page = page_pool_refill_alloc_cache(pool);
refill = true;
} }
page = page_pool_refill_alloc_cache(pool, refill);
return page; return page;
} }
......
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