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[24.9.64.241]) by smtp.gmail.com with ESMTPSA id n65sm905604ila.69.2020.05.08.08.07.26 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 08 May 2020 08:07:27 -0700 (PDT) Subject: Re: [PATCH 1/2] fs: avoid fdput() after failed fdget() in ksys_sync_file_range() To: Luis Chamberlain , Al Viro Cc: axboe@kernel.dk, zohar@linux.vnet.ibm.com, keescook@chromium.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan References: <31be6e0896eba59c06eb9d3d137b214f7220cc53.1588894359.git.skhan@linuxfoundation.org> <20200508000509.GK23230@ZenIV.linux.org.uk> <20200508002422.GL23230@ZenIV.linux.org.uk> <20200508022139.GD11244@42.do-not-panic.com> From: Shuah Khan Message-ID: <7d3e7bf5-22e4-ab3d-798e-33d3657e1cf1@linuxfoundation.org> Date: Fri, 8 May 2020 09:07:26 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200508022139.GD11244@42.do-not-panic.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/7/20 8:21 PM, Luis Chamberlain wrote: > On Fri, May 08, 2020 at 01:24:22AM +0100, Al Viro wrote: >> On Fri, May 08, 2020 at 01:05:09AM +0100, Al Viro wrote: >>> On Thu, May 07, 2020 at 05:57:09PM -0600, Shuah Khan wrote: >>>> Fix ksys_sync_file_range() to avoid fdput() after a failed fdget(). >>>> fdput() doesn't do fput() on this file since FDPUT_FPUT isn't set >>>> in fd.flags. Fix it anyway since failed fdget() doesn't require >>>> a fdput(). >>>> >>>> This was introdcued in a commit to add sync_file_range() helper. >>> >>> Er... What's the point microoptimizing the slow path here? >> >> PS: I'm not saying the patch is incorrect, but Fixes: is IMO over the >> top. And looking at that thing, >> { >> struct fd f = fdget(fd); >> int ret; >> >> if (unlikely(!f.file)) >> return -EBADF; >> >> ret = sync_file_range(f.file, offset, nbytes, flags); >> fdput(f); >> return ret; >> } >> >> might be cleaner, but that's a matter of taste... > > This makes it easier to read. > Yes it does. I will make the changes and send v2. thanks, -- Shuah