Received-SPF: pass (google.com: domain of linux-kernel+bounces-98196-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45e3:2400::1 as permitted sender) client-ip=2604:1380:45e3:2400::1;
Date: Sun, 10 Mar 2024 13:33:06 +0200
From: Leon Romanovsky <leon@kernel.org>
To: linke li <lilinke99@qq.com>
Cc: Bernard Metzler <bmt@zurich.ibm.com>, Jason Gunthorpe <jgg@ziepe.ca>,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] RDMA/siw: Reuse value read using READ_ONCE instead of
 re-reading it
Message-ID: <20240310113306.GF12921@unreal>
References: <tencent_32C3AEB0599DF0A0010A862439636CDA2707@qq.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <tencent_32C3AEB0599DF0A0010A862439636CDA2707@qq.com>

On Sat, Mar 09, 2024 at 08:27:16PM +0800, linke li wrote:
> In siw_orqe_start_rx, the orqe's flag in the if condition is read using
> READ_ONCE, checked, and then re-read, voiding all guarantees of the
> checks. Reuse the value that was read by READ_ONCE to ensure the
> consistency of the flags throughout the function.

Please read include/asm-generic/rwonce.h comments when READ_ONCE() is used.
There is no value in caching the output of READ_ONCE().

Thanks