From: Jakub Kicinski <kuba@kernel.org>
To: Michal Luczaj <mhal@rbox.co>
Cc: "David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Cong Wang <cong.wang@bytedance.com>,
Tom Herbert <tom@herbertland.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] kcm: Fix splice support
Date: Wed, 30 Jul 2025 18:02:15 -0700 [thread overview]
Message-ID: <20250730180215.2ad7df72@kernel.org> (raw)
In-Reply-To: <20250725-kcm-splice-v1-1-9a725ad2ee71@rbox.co>
On Fri, 25 Jul 2025 12:33:04 +0200 Michal Luczaj wrote:
> Flags passed in for splice() syscall should not end up in
> skb_recv_datagram(). As SPLICE_F_NONBLOCK == MSG_PEEK, kernel gets
> confused: skb isn't unlinked from a receive queue, while strp_msg::offset
> and strp_msg::full_len are updated.
>
> Unbreak the logic a bit more by mapping both O_NONBLOCK and
> SPLICE_F_NONBLOCK to MSG_DONTWAIT. This way we align with man splice(2) in
> regard to errno EAGAIN:
>
> SPLICE_F_NONBLOCK was specified in flags or one of the file descriptors
> had been marked as nonblocking (O_NONBLOCK), and the operation would
> block.
Coincidentally looks like we're not honoring
sock->file->f_flags & O_NONBLOCK
in TLS..
next prev parent reply other threads:[~2025-07-31 1:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-25 10:33 Michal Luczaj
2025-07-31 1:02 ` Jakub Kicinski [this message]
2025-08-03 10:00 ` Michal Luczaj
2025-08-04 23:51 ` Jakub Kicinski
2025-08-06 21:15 ` Michal Luczaj
2025-07-31 1:10 ` patchwork-bot+netdevbpf
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