[PATCH net-next v1 06/11] page_pool: introduce page_pool_free and use in mlx5

Jesper Dangaard Brouer
2019-06-13T18:28:38Z

In case driver fails to register the page_pool with XDP return API (via
xdp_rxq_info_reg_mem_model()), then the driver can free the page_pool
resources more directly than calling page_pool_destroy(), which does a
unnecessarily RCU free procedure.

This patch is preparing for removing page_pool_destroy(), from driver
invocation.

Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Tariq Toukan <tariqt@mellanox.com>
---
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 6 +++---
include/net/page_pool.h | 11 +++++++++++
net/core/page_pool.c | 15 +++++++++++----
3 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index 457cc39423f2..07de9ca4c53c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -545,8 +545,10 @@ 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)
+ if (err) {
+ page_pool_free(rq->page_pool);
goto err_free;
+ }

for (i = 0; i < wq_sz; i++) {
if (rq->wq_type == MLX5_WQ_TYPE_LINKED_LIST_STRIDING_RQ) {
@@ -611,8 +613,6 @@ 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);
- if (rq->page_pool)
- page_pool_destroy(rq->page_pool);
mlx5_wq_destroy(&rq->wq_ctrl);

return err;
diff --git a/include/net/page_pool.h b/include/net/page_pool.h
index e240fac4c5b9..754d980700df 100644
--- a/include/net/page_pool.h
+++ b/include/net/page_pool.h
@@ -111,6 +111,17 @@ struct page_pool *page_pool_create(const struct page_pool_params *params);

void page_pool_destroy(struct page_pool *pool);

+void __page_pool_free(struct page_pool *pool);
+static inline void page_pool_free(struct page_pool *pool)
+{
+ /* When page_pool isn't compiled-in, net/core/xdp.c doesn't
+ * allow registering MEM_TYPE_PAGE_POOL, but shield linker.
+ */
+#ifdef CONFIG_PAGE_POOL
+ __page_pool_free(pool);
+#endif
+}
+
/* Never call this directly, use helpers below */
void __page_pool_put_page(struct page_pool *pool,
struct page *page, bool allow_direct);
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 205af7bd6d09..41391b5dc14c 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -292,17 +292,24 @@ static void __page_pool_empty_ring(struct page_pool *pool)
}
}

+void __page_pool_free(struct page_pool *pool)
+{
+ WARN(pool->alloc.count, "API usage violation");
+ WARN(!ptr_ring_empty(&pool->ring), "ptr_ring is not empty");
+
+ ptr_ring_cleanup(&pool->ring, NULL);
+ kfree(pool);
+}
+EXPORT_SYMBOL(__page_pool_free);
+
static void __page_pool_destroy_rcu(struct rcu_head *rcu)
{
struct page_pool *pool;

pool = container_of(rcu, struct page_pool, rcu);

- WARN(pool->alloc.count, "API usage violation");
-
__page_pool_empty_ring(pool);
- ptr_ring_cleanup(&pool->ring, NULL);
- kfree(pool);
+ __page_pool_free(pool);
}

/* Cleanup and release resources */