@@ -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);
}
@@ -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);
@@ -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 */
@@ -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");
@@ -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);
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 <brouer@redhat.com> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@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(-)