From: Dominique Martinet <asmadeus@codewreck.org>
To: Gui-Dong Han <hanguidong02@gmail.com>
Cc: ericvh@kernel.org, lucho@ionkov.net, linux_oss@crudebyte.com,
v9fs@lists.linux.dev, linux-kernel@vger.kernel.org,
baijiaju1990@gmail.com
Subject: Re: [PATCH] 9p: Add missing read barrier in virtio zero-copy path
Date: Mon, 15 Jun 2026 22:13:31 +0900 [thread overview]
Message-ID: <ai_6e8Rhfq1coHw_@codewreck.org> (raw)
In-Reply-To: <20260529075441.233369-1-hanguidong02@gmail.com>
Gui-Dong Han wrote on Fri, May 29, 2026 at 03:54:41PM +0800:
> Commit 2b6e72ed747f ("9P: Add memory barriers to protect request
> fields over cb/rpc threads handoff") added a read barrier after
> p9_client_rpc() waits for req->status, pairing with the write barrier in
> p9_client_cb(). The virtio zero-copy wait path was missed.
>
> Add the same read barrier after the zero-copy wait before reading the
> completed request.
>
> Fixes: abfa034e4b8e ("fs/9p: Update zero-copy implementation in 9p")
This doesn't make sense, the wmb was added a few years later, so I guess
this should be
Fixes: 2b6e72ed747f ("9P: Add memory barriers to protect request fields over cb/rpc threads handoff")
With that said, a rmb here makes sense, so picking up (with fix tag
fixed up)
--
Dominique
prev parent reply other threads:[~2026-06-15 13:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-29 7:54 [PATCH] 9p: Add missing read barrier in virtio zero-copy path Gui-Dong Han
2026-06-15 13:13 ` Dominique Martinet [this message]
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