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[109.252.170.211]) by smtp.googlemail.com with ESMTPSA id n8sm418776ljj.69.2020.09.29.10.42.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 29 Sep 2020 10:42:53 -0700 (PDT) Subject: Re: [PATCH v4 2/2] iommu/tegra-smmu: Expand mutex protection range To: Nicolin Chen , thierry.reding@gmail.com, joro@8bytes.org Cc: vdumpa@nvidia.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, hch@infradead.org References: <20200929061325.10197-1-nicoleotsuka@gmail.com> <20200929061325.10197-3-nicoleotsuka@gmail.com> From: Dmitry Osipenko Message-ID: <184163e9-01d4-dcc5-0adf-a3d175e56f16@gmail.com> Date: Tue, 29 Sep 2020 20:42:52 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200929061325.10197-3-nicoleotsuka@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 29.09.2020 09:13, Nicolin Chen пишет: > This is used to protect potential race condition at use_count. > since probes of client drivers, calling attach_dev(), may run > concurrently. > > Signed-off-by: Nicolin Chen > --- It's always better not to mix success and error code paths in order to keep code readable, but not a big deal in the case of this particular patch since the changed code is quite simple. Please try to avoid doing this in the future patches. Also, please note that in general it's better to use locked/unlocked versions for the functions like it's already done for tegra_smmu_map/unmap, this will remove the need to maintain lockings in the code. The code touched by this patch doesn't have complicated code paths, so it's good enough to me. Reviewed-by: Dmitry Osipenko