Re: [PATCH V2 net-next 6/7] tap: support receiving skb from msg_control
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2017-03-30 15:03:09
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On Thu, Mar 30, 2017 at 03:22:29PM +0800, Jason Wang wrote:
quoted hunk ↗ jump to hunk
This patch makes tap_recvmsg() can receive from skb from its caller through msg_control. Vhost_net will be the first user. Signed-off-by: Jason Wang <jasowang@redhat.com> --- drivers/net/tap.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)diff --git a/drivers/net/tap.c b/drivers/net/tap.c index abdaf86..07d9174 100644 --- a/drivers/net/tap.c +++ b/drivers/net/tap.c@@ -824,15 +824,17 @@ static ssize_t tap_put_user(struct tap_queue *q, static ssize_t tap_do_read(struct tap_queue *q, struct iov_iter *to, - int noblock) + int noblock, struct sk_buff *skb) { DEFINE_WAIT(wait); - struct sk_buff *skb; ssize_t ret = 0; if (!iov_iter_count(to)) return 0; + if (skb) + goto done; + while (1) { if (!noblock) prepare_to_wait(sk_sleep(&q->sk), &wait,@@ -856,6 +858,7 @@ static ssize_t tap_do_read(struct tap_queue *q, if (!noblock) finish_wait(sk_sleep(&q->sk), &wait); +done:
Please just use an if {} block here. goto on error is ok,
but we are far from done here and goto done is misleading.
quoted hunk ↗ jump to hunk
if (skb) { ret = tap_put_user(q, skb, to); if (unlikely(ret < 0))@@ -872,7 +875,7 @@ static ssize_t tap_read_iter(struct kiocb *iocb, struct iov_iter *to) struct tap_queue *q = file->private_data; ssize_t len = iov_iter_count(to), ret; - ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK); + ret = tap_do_read(q, to, file->f_flags & O_NONBLOCK, NULL); ret = min_t(ssize_t, ret, len); if (ret > 0) iocb->ki_pos = ret;@@ -1155,7 +1158,8 @@ static int tap_recvmsg(struct socket *sock, struct msghdr *m, int ret; if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) return -EINVAL; - ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT); + ret = tap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT, + m->msg_control); if (ret > total_len) { m->msg_flags |= MSG_TRUNC; ret = flags & MSG_TRUNC ? ret : total_len;-- 2.7.4