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[173.197.98.125]) by smtp.gmail.com with ESMTPSA id e18-20020a656792000000b005dc389409c1sm10901115pgr.93.2024.02.23.10.21.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 23 Feb 2024 10:21:45 -0800 (PST) Message-ID: <808e13f8-11da-4ec1-969d-d2495cbd3a88@linaro.org> Date: Fri, 23 Feb 2024 08:21:42 -1000 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] atomic.h: Reword confusing comment for qatomic_cmpxchg Content-Language: en-US To: Peter Maydell , qemu-devel@nongnu.org Cc: Jonathan Cameron References: <20240223182035.1048541-1-peter.maydell@linaro.org> From: Richard Henderson In-Reply-To: <20240223182035.1048541-1-peter.maydell@linaro.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=2607:f8b0:4864:20::434; envelope-from=richard.henderson@linaro.org; helo=mail-pf1-x434.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 2/23/24 08:20, Peter Maydell wrote: > The qatomic_cmpxchg() and qatomic_cmpxchg__nocheck() macros have > a comment that reads: > Returns the eventual value, failed or not > > This is somewhere between cryptic and wrong, since the value actually > returned is the value that was in memory before the cmpxchg. Reword > to match how we describe these macros in atomics.rst. > > Signed-off-by: Peter Maydell > --- > include/qemu/atomic.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h > index f1d3d1702a9..99110abefb3 100644 > --- a/include/qemu/atomic.h > +++ b/include/qemu/atomic.h > @@ -202,7 +202,7 @@ > qatomic_xchg__nocheck(ptr, i); \ > }) > > -/* Returns the eventual value, failed or not */ > +/* Returns the old value of '*ptr' (whether the cmpxchg failed or not) */ > #define qatomic_cmpxchg__nocheck(ptr, old, new) ({ \ > typeof_strip_qual(*ptr) _old = (old); \ > (void)__atomic_compare_exchange_n(ptr, &_old, new, false, \ Reviewed-by: Richard Henderson r~