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authorBjörn Töpel <bjorn.topel@intel.com>2020-11-30 21:51:59 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2020-12-01 02:09:25 +0300
commite392081837283fbe5df1837fd85012ae5bfae098 (patch)
treef0c1d7ea91db4dfc7f03b59818246ac15d9ca2a7 /net/xdp
parent45a86681844e375bef6f6add272ccc309bb6a08d (diff)
downloadlinux-e392081837283fbe5df1837fd85012ae5bfae098.tar.xz
xsk: Check need wakeup flag in sendmsg()
Add a check for need wake up in sendmsg(), so that if a user calls sendmsg() when no wakeup is needed, do not trigger a wakeup. To simplify the need wakeup check in the syscall, unconditionally enable the need wakeup flag for Tx. This has a side-effect for poll(); If poll() is called for a socket without enabled need wakeup, a Tx wakeup is unconditionally performed. The wakeup matrix for AF_XDP now looks like: need wakeup | poll() | sendmsg() | recvmsg() ------------+--------------+-------------+------------ disabled | wake Tx | wake Tx | nop enabled | check flag; | check flag; | check flag; | wake Tx/Rx | wake Tx | wake Rx Signed-off-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Magnus Karlsson <magnus.karlsson@intel.com> Link: https://lore.kernel.org/bpf/20201130185205.196029-5-bjorn.topel@gmail.com
Diffstat (limited to 'net/xdp')
-rw-r--r--net/xdp/xsk.c6
-rw-r--r--net/xdp/xsk_buff_pool.c13
2 files changed, 11 insertions, 8 deletions
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 1d1e0cd51a95..c72b4dba2878 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -522,13 +522,17 @@ static int xsk_sendmsg(struct socket *sock, struct msghdr *m, size_t total_len)
bool need_wait = !(m->msg_flags & MSG_DONTWAIT);
struct sock *sk = sock->sk;
struct xdp_sock *xs = xdp_sk(sk);
+ struct xsk_buff_pool *pool;
if (unlikely(!xsk_is_bound(xs)))
return -ENXIO;
if (unlikely(need_wait))
return -EOPNOTSUPP;
- return __xsk_sendmsg(sk);
+ pool = xs->pool;
+ if (pool->cached_need_wakeup & XDP_WAKEUP_TX)
+ return __xsk_sendmsg(sk);
+ return 0;
}
static int xsk_recvmsg(struct socket *sock, struct msghdr *m, size_t len, int flags)
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 8a3bf4e1318e..96bb607853ad 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -144,14 +144,13 @@ static int __xp_assign_dev(struct xsk_buff_pool *pool,
if (err)
return err;
- if (flags & XDP_USE_NEED_WAKEUP) {
+ if (flags & XDP_USE_NEED_WAKEUP)
pool->uses_need_wakeup = true;
- /* Tx needs to be explicitly woken up the first time.
- * Also for supporting drivers that do not implement this
- * feature. They will always have to call sendto().
- */
- pool->cached_need_wakeup = XDP_WAKEUP_TX;
- }
+ /* Tx needs to be explicitly woken up the first time. Also
+ * for supporting drivers that do not implement this
+ * feature. They will always have to call sendto() or poll().
+ */
+ pool->cached_need_wakeup = XDP_WAKEUP_TX;
dev_hold(netdev);