2023-12-01 06:11:14

by Yewon Choi

Subject: [PATCH bpf] xsk: skip polling event check for unbound socket

In xsk_poll(), checking available events and setting mask bits should
be executed only when a socket has been bound. Setting mask bits for
unbound socket is meaningless.
Currently, it checks events even when xsk_check_common() failed.
To prevent this, we move goto location (skip_tx) after that checking.

Fixes: 1596dae2f17e ("xsk: check IFF_UP earlier in Tx path")
Signed-off-by: Yewon Choi <[email protected]>
---
net/xdp/xsk.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index ae9f8cb611f6..1e5a65326d1d 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -947,7 +947,7 @@ static __poll_t xsk_poll(struct file *file, struct socket *sock,

rcu_read_lock();
if (xsk_check_common(xs))
- goto skip_tx;
+ goto out;

pool = xs->pool;

@@ -959,12 +959,12 @@ static __poll_t xsk_poll(struct file *file, struct socket *sock,
xsk_generic_xmit(sk);
}

-skip_tx:
if (xs->rx && !xskq_prod_is_empty(xs->rx))
mask |= EPOLLIN | EPOLLRDNORM;
if (xs->tx && xsk_tx_writeable(xs))
mask |= EPOLLOUT | EPOLLWRNORM;

+out:
rcu_read_unlock();
return mask;
}
--
2.37.3

2023-12-05 09:04:02

by Magnus Karlsson

Subject: Re: [PATCH bpf] xsk: skip polling event check for unbound socket

On Fri, 1 Dec 2023 at 07:11, Yewon Choi <[email protected]> wrote:
>
> In xsk_poll(), checking available events and setting mask bits should
> be executed only when a socket has been bound. Setting mask bits for
> unbound socket is meaningless.
> Currently, it checks events even when xsk_check_common() failed.
> To prevent this, we move goto location (skip_tx) after that checking.

Thanks for the fix.

Acked-by: Magnus Karlsson <[email protected]>

> Fixes: 1596dae2f17e ("xsk: check IFF_UP earlier in Tx path")
> Signed-off-by: Yewon Choi <[email protected]>
> ---
> net/xdp/xsk.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index ae9f8cb611f6..1e5a65326d1d 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -947,7 +947,7 @@ static __poll_t xsk_poll(struct file *file, struct socket *sock,
>
> rcu_read_lock();
> if (xsk_check_common(xs))
> - goto skip_tx;
> + goto out;
>
> pool = xs->pool;
>
> @@ -959,12 +959,12 @@ static __poll_t xsk_poll(struct file *file, struct socket *sock,
> xsk_generic_xmit(sk);
> }
>
> -skip_tx:
> if (xs->rx && !xskq_prod_is_empty(xs->rx))
> mask |= EPOLLIN | EPOLLRDNORM;
> if (xs->tx && xsk_tx_writeable(xs))
> mask |= EPOLLOUT | EPOLLWRNORM;
>
> +out:
> rcu_read_unlock();
> return mask;
> }
> --
> 2.37.3
>
>

2023-12-05 12:51:17

by patchwork-bot+netdevbpf

Subject: Re: [PATCH bpf] xsk: skip polling event check for unbound socket

Hello:

This patch was applied to bpf/bpf.git (master)
by Daniel Borkmann <[email protected]>:

On Fri, 1 Dec 2023 15:10:52 +0900 you wrote:
> In xsk_poll(), checking available events and setting mask bits should
> be executed only when a socket has been bound. Setting mask bits for
> unbound socket is meaningless.
> Currently, it checks events even when xsk_check_common() failed.
> To prevent this, we move goto location (skip_tx) after that checking.
>
> Fixes: 1596dae2f17e ("xsk: check IFF_UP earlier in Tx path")
> Signed-off-by: Yewon Choi <[email protected]>
>
> [...]

Here is the summary with links:
- [bpf] xsk: skip polling event check for unbound socket
https://git.kernel.org/bpf/bpf/c/e4d008d49a71

You are awesome, thank you!
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