From 1da4bbeffe41ba318812d7590955faee8636668b Mon Sep 17 00:00:00 2001 From: Ivan Khoronzhuk Date: Tue, 9 Jul 2019 00:34:28 +0300 Subject: net: core: page_pool: add user refcnt and reintroduce page_pool_destroy Jesper recently removed page_pool_destroy() (from driver invocation) and moved shutdown and free of page_pool into xdp_rxq_info_unreg(), in-order to handle in-flight packets/pages. This created an asymmetry in drivers create/destroy pairs. This patch reintroduce page_pool_destroy and add page_pool user refcnt. This serves the purpose to simplify drivers error handling as driver now drivers always calls page_pool_destroy() and don't need to track if xdp_rxq_info_reg_mem_model() was unsuccessful. This could be used for a special cases where a single RX-queue (with a single page_pool) provides packets for two net_device'es, and thus needs to register the same page_pool twice with two xdp_rxq_info structures. This patch is primarily to ease API usage for drivers. The recently merged netsec driver, actually have a bug in this area, which is solved by this API change. This patch is a modified version of Ivan Khoronzhuk's original patch. Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronzhuk@linaro.org/ Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API") Signed-off-by: Jesper Dangaard Brouer Reviewed-by: Ilias Apalodimas Acked-by: Jesper Dangaard Brouer Reviewed-by: Saeed Mahameed Signed-off-by: Ivan Khoronzhuk Signed-off-by: David S. Miller --- include/net/page_pool.h | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'include/net') diff --git a/include/net/page_pool.h b/include/net/page_pool.h index ee9c871d2043..2cbcdbdec254 100644 --- a/include/net/page_pool.h +++ b/include/net/page_pool.h @@ -101,6 +101,12 @@ struct page_pool { struct ptr_ring ring; atomic_t pages_state_release_cnt; + + /* A page_pool is strictly tied to a single RX-queue being + * protected by NAPI, due to above pp_alloc_cache. This + * refcnt serves purpose is to simplify drivers error handling. + */ + refcount_t user_cnt; }; struct page *page_pool_alloc_pages(struct page_pool *pool, gfp_t gfp); @@ -134,6 +140,15 @@ static inline void page_pool_free(struct page_pool *pool) #endif } +/* Drivers use this instead of page_pool_free */ +static inline void page_pool_destroy(struct page_pool *pool) +{ + if (!pool) + return; + + page_pool_free(pool); +} + /* Never call this directly, use helpers below */ void __page_pool_put_page(struct page_pool *pool, struct page *page, bool allow_direct); @@ -201,4 +216,14 @@ static inline bool is_page_pool_compiled_in(void) #endif } +static inline void page_pool_get(struct page_pool *pool) +{ + refcount_inc(&pool->user_cnt); +} + +static inline bool page_pool_put(struct page_pool *pool) +{ + return refcount_dec_and_test(&pool->user_cnt); +} + #endif /* _NET_PAGE_POOL_H */ -- cgit v1.2.3