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 Khoronzhu's original patch. Link: https://lore.kernel.org/netdev/20190625175948.24771-2-ivan.khoronz...@linaro.org/ Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API") Signed-off-by: Jesper Dangaard Brouer <bro...@redhat.com> Reviewed-by: Ilias Apalodimas <ilias.apalodi...@linaro.org> Signed-off-by: Ivan Khoronzhuk <ivan.khoronz...@linaro.org> --- .../net/ethernet/mellanox/mlx5/core/en_main.c | 4 +-- drivers/net/ethernet/socionext/netsec.c | 8 ++---- include/net/page_pool.h | 25 +++++++++++++++++++ net/core/page_pool.c | 8 ++++++ net/core/xdp.c | 3 +++ 5 files changed, 40 insertions(+), 8 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c index 2f9093ba82aa..ac882b2341d0 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c @@ -575,8 +575,6 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c, } err = xdp_rxq_info_reg_mem_model(&rq->xdp_rxq, MEM_TYPE_PAGE_POOL, rq->page_pool); - if (err) - page_pool_free(rq->page_pool); } if (err) goto err_free; @@ -644,6 +642,7 @@ static int mlx5e_alloc_rq(struct mlx5e_channel *c, if (rq->xdp_prog) bpf_prog_put(rq->xdp_prog); xdp_rxq_info_unreg(&rq->xdp_rxq); + page_pool_destroy(rq->page_pool); mlx5_wq_destroy(&rq->wq_ctrl); return err; @@ -678,6 +677,7 @@ static void mlx5e_free_rq(struct mlx5e_rq *rq) } xdp_rxq_info_unreg(&rq->xdp_rxq); + page_pool_destroy(rq->page_pool); mlx5_wq_destroy(&rq->wq_ctrl); } diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c index 5544a722543f..43ab0ce90704 100644 --- a/drivers/net/ethernet/socionext/netsec.c +++ b/drivers/net/ethernet/socionext/netsec.c @@ -1210,15 +1210,11 @@ static void netsec_uninit_pkt_dring(struct netsec_priv *priv, int id) } } - /* Rx is currently using page_pool - * since the pool is created during netsec_setup_rx_dring(), we need to - * free the pool manually if the registration failed - */ + /* Rx is currently using page_pool */ if (id == NETSEC_RING_RX) { if (xdp_rxq_info_is_reg(&dring->xdp_rxq)) xdp_rxq_info_unreg(&dring->xdp_rxq); - else - page_pool_free(dring->page_pool); + page_pool_destroy(dring->page_pool); } memset(dring->desc, 0, sizeof(struct netsec_desc) * DESC_NUM); 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 */ diff --git a/net/core/page_pool.c b/net/core/page_pool.c index b366f59885c1..3272dc7a8c81 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -49,6 +49,9 @@ static int page_pool_init(struct page_pool *pool, atomic_set(&pool->pages_state_release_cnt, 0); + /* Driver calling page_pool_create() also call page_pool_destroy() */ + refcount_set(&pool->user_cnt, 1); + if (pool->p.flags & PP_FLAG_DMA_MAP) get_device(pool->p.dev); @@ -70,6 +73,7 @@ struct page_pool *page_pool_create(const struct page_pool_params *params) kfree(pool); return ERR_PTR(err); } + return pool; } EXPORT_SYMBOL(page_pool_create); @@ -356,6 +360,10 @@ static void __warn_in_flight(struct page_pool *pool) void __page_pool_free(struct page_pool *pool) { + /* Only last user actually free/release resources */ + if (!page_pool_put(pool)) + return; + WARN(pool->alloc.count, "API usage violation"); WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty"); diff --git a/net/core/xdp.c b/net/core/xdp.c index 829377cc83db..d7bf62ffbb5e 100644 --- a/net/core/xdp.c +++ b/net/core/xdp.c @@ -370,6 +370,9 @@ int xdp_rxq_info_reg_mem_model(struct xdp_rxq_info *xdp_rxq, goto err; } + if (type == MEM_TYPE_PAGE_POOL) + page_pool_get(xdp_alloc->page_pool); + mutex_unlock(&mem_id_lock); trace_mem_connect(xdp_alloc, xdp_rxq); -- 2.17.1
