From b5aea28dca13456c1a08b9b2ef8a8b92598ac426 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Fri, 28 Aug 2020 10:26:25 +0200 Subject: [PATCH] xsk: Add shared umem support between queue ids MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add support to share a umem between queue ids on the same device. This mode can be invoked with the XDP_SHARED_UMEM bind flag. Previously, sharing was only supported within the same queue id and device, and you shared one set of fill and completion rings. However, note that when sharing a umem between queue ids, you need to create a fill ring and a completion ring and tie them to the socket before you do the bind with the XDP_SHARED_UMEM flag. This so that the single-producer single-consumer semantics can be upheld. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/1598603189-32145-12-git-send-email-magnus.karlsson@intel.com --- include/net/xsk_buff_pool.h | 2 ++ net/xdp/xsk.c | 44 +++++++++++++++++++++++++------------ net/xdp/xsk_buff_pool.c | 26 ++++++++++++++++++++-- 3 files changed, 56 insertions(+), 16 deletions(-) diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h index 907537dddcac..0140d086dc84 100644 --- a/include/net/xsk_buff_pool.h +++ b/include/net/xsk_buff_pool.h @@ -81,6 +81,8 @@ struct xsk_buff_pool *xp_create_and_assign_umem(struct xdp_sock *xs, struct xdp_umem *umem); int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *dev, u16 queue_id, u16 flags); +int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem, + struct net_device *dev, u16 queue_id); void xp_destroy(struct xsk_buff_pool *pool); void xp_release(struct xdp_buff_xsk *xskb); void xp_get_pool(struct xsk_buff_pool *pool); diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 067e85424d36..ea8d2ec8386e 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -689,12 +689,6 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) goto out_unlock; } - if (xs->fq_tmp || xs->cq_tmp) { - /* Do not allow setting your own fq or cq. */ - err = -EINVAL; - goto out_unlock; - } - sock = xsk_lookup_xsk_from_fd(sxdp->sxdp_shared_umem_fd); if (IS_ERR(sock)) { err = PTR_ERR(sock); @@ -707,15 +701,41 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) sockfd_put(sock); goto out_unlock; } - if (umem_xs->dev != dev || umem_xs->queue_id != qid) { + if (umem_xs->dev != dev) { err = -EINVAL; sockfd_put(sock); goto out_unlock; } - /* Share the buffer pool with the other socket. */ - xp_get_pool(umem_xs->pool); - xs->pool = umem_xs->pool; + if (umem_xs->queue_id != qid) { + /* Share the umem with another socket on another qid */ + xs->pool = xp_create_and_assign_umem(xs, + umem_xs->umem); + if (!xs->pool) { + sockfd_put(sock); + goto out_unlock; + } + + err = xp_assign_dev_shared(xs->pool, umem_xs->umem, + dev, qid); + if (err) { + xp_destroy(xs->pool); + sockfd_put(sock); + goto out_unlock; + } + } else { + /* Share the buffer pool with the other socket. */ + if (xs->fq_tmp || xs->cq_tmp) { + /* Do not allow setting your own fq or cq. */ + err = -EINVAL; + sockfd_put(sock); + goto out_unlock; + } + + xp_get_pool(umem_xs->pool); + xs->pool = umem_xs->pool; + } + xdp_get_umem(umem_xs->umem); WRITE_ONCE(xs->umem, umem_xs->umem); sockfd_put(sock); @@ -847,10 +867,6 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, mutex_unlock(&xs->mutex); return -EBUSY; } - if (!xs->umem) { - mutex_unlock(&xs->mutex); - return -EINVAL; - } q = (optname == XDP_UMEM_FILL_RING) ? &xs->fq_tmp : &xs->cq_tmp; diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c index 547eb41f7837..795d7c81c0ca 100644 --- a/net/xdp/xsk_buff_pool.c +++ b/net/xdp/xsk_buff_pool.c @@ -123,8 +123,8 @@ static void xp_disable_drv_zc(struct xsk_buff_pool *pool) } } -int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *netdev, - u16 queue_id, u16 flags) +static int __xp_assign_dev(struct xsk_buff_pool *pool, + struct net_device *netdev, u16 queue_id, u16 flags) { bool force_zc, force_copy; struct netdev_bpf bpf; @@ -193,6 +193,28 @@ int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *netdev, return err; } +int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *dev, + u16 queue_id, u16 flags) +{ + return __xp_assign_dev(pool, dev, queue_id, flags); +} + +int xp_assign_dev_shared(struct xsk_buff_pool *pool, struct xdp_umem *umem, + struct net_device *dev, u16 queue_id) +{ + u16 flags; + + /* One fill and completion ring required for each queue id. */ + if (!pool->fq || !pool->cq) + return -EINVAL; + + flags = umem->zc ? XDP_ZEROCOPY : XDP_COPY; + if (pool->uses_need_wakeup) + flags |= XDP_USE_NEED_WAKEUP; + + return __xp_assign_dev(pool, dev, queue_id, flags); +} + void xp_clear_dev(struct xsk_buff_pool *pool) { if (!pool->netdev)