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([2a02:810d:15c0:828:bcb8:77e6:8f45:4771]) by smtp.gmail.com with ESMTPSA id l22-20020aa7c3d6000000b00506be898998sm588954edr.29.2023.04.20.03.16.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 20 Apr 2023 03:16:28 -0700 (PDT) From: Krzysztof Kozlowski To: Vinod Koul , Bard Liao , Pierre-Louis Bossart , Sanyog Kale , Andy Gross , Bjorn Andersson , Konrad Dybcio , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org Cc: Krzysztof Kozlowski , Patrick Lai Subject: [PATCH 5/6] soudnwire: master: protect concurrecnt check for bus->md Date: Thu, 20 Apr 2023 12:16:16 +0200 Message-Id: <20230420101617.142225-6-krzysztof.kozlowski@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230420101617.142225-1-krzysztof.kozlowski@linaro.org> References: <20230420101617.142225-1-krzysztof.kozlowski@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The Soundwire master controllers might want to check for bus->md initialization to avoid race between early interrupt and finish of sdw_bus_master_add()/sdw_master_device_add(). Such early interrupt can happen if Soundwire devices are not powered off during their probe. Add a store release barrier, so the Soundwire controllers can safely check it in concurrent (e.g. in interrupt) way. Signed-off-by: Krzysztof Kozlowski --- Cc: Patrick Lai --- drivers/soundwire/master.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/soundwire/master.c b/drivers/soundwire/master.c index 9b05c9e25ebe..d5bf13e7e602 100644 --- a/drivers/soundwire/master.c +++ b/drivers/soundwire/master.c @@ -161,7 +161,12 @@ int sdw_master_device_add(struct sdw_bus *bus, struct = device *parent, /* add shortcuts to improve code readability/compactness */ md->bus =3D bus; bus->dev =3D &md->dev; - bus->md =3D md; + /* + * Make sure the contents of md is stored before storing bus->md. + * Paired with new slave attached and slave status interrupts + * on the Soundwire master side. + */ + smp_store_release(&bus->md, md); =20 pm_runtime_set_autosuspend_delay(&bus->md->dev, SDW_MASTER_SUSPEND_DELAY_= MS); pm_runtime_use_autosuspend(&bus->md->dev); --=20 2.34.1