CC: Tariq + Saeed, could you please review the mlx5 part. On Fri, 5 Jul 2019 02:14:02 +0300 Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> wrote: > 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.khoronzhuk@xxxxxxxxxx/ > Fixes: 5c67bf0ec4d0 ("net: netsec: Use page_pool API") > Signed-off-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> > Reviewed-by: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx> > Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@xxxxxxxxxx> Acked-by: Jesper Dangaard Brouer <brouer@xxxxxxxxxx> Thank you Ivan for taking this more simple approach. If we later see more drivers wanting this feature of a single RX-queue providing packets to multiple net_device'es, then we can change into your more generic API at XDP-reg-layer approach later. For now, we keep code complexity as low as possible. > --- > .../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); -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
