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AJvYcCW46JtIwCUVbaRb2d72G+lKUfaw44S/+7OXbj4P2O4Y/eOG6G/tULsXofkRAd2y9K5pXaHRj9EAfVWC8ib+FwL5ffrm4DDi7z1dxxZg X-Gm-Message-State: AOJu0YxbuKkEsLcTlyrsvoC7o34tUgC4rf7yL8T+riG8tI+URKB9QjT8 O1qTEjSlCGku4flZjvcsakUvzG4qMWo2IUzS0CUwt3KXs4NDYqFtHaT7Z1d2YUE= X-Google-Smtp-Source: AGHT+IF+Cyeo2mWoylUN+f5sX3aHqZjl0czKC66QZp6hGbPe4oQB/7UWKaqNwH8HfMckY+LPhaXuhw== X-Received: by 2002:a17:903:41cf:b0:1db:ce31:96b1 with SMTP id u15-20020a17090341cf00b001dbce3196b1mr478555ple.6.1709647142261; Tue, 05 Mar 2024 05:59:02 -0800 (PST) Received: from [192.168.1.150] ([198.8.77.194]) by smtp.gmail.com with ESMTPSA id ld4-20020a170902fac400b001db5b39635dsm10625132plb.277.2024.03.05.05.59.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Mar 2024 05:59:01 -0800 (PST) Message-ID: Date: Tue, 5 Mar 2024 06:58:59 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] coredump: get machine check errors early rather than during iov_iter Content-Language: en-US To: Tong Tiangen , Linus Torvalds , David Howells , Al Viro , Alexander Viro , Christian Brauner , Jan Kara , Andrew Morton Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, wangkefeng.wang@huawei.com, Guohanjun References: <20240305133336.3804360-1-tongtiangen@huawei.com> From: Jens Axboe In-Reply-To: <20240305133336.3804360-1-tongtiangen@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/5/24 6:33 AM, Tong Tiangen wrote: > The commit f1982740f5e7 ("iov_iter: Convert iterate*() to inline funcs") > leads to deadloop in generic_perform_write()[1], due to return value of > copy_page_from_iter_atomic() changed from non-zero value to zero. > > The code logic of the I/O performance-critical path of the iov_iter is > mixed with machine check[2], actually, there's no need to complicate it, > a more appropriate method is to get the error as early as possible in > the coredump process instead of during the I/O process. In addition, > the iov_iter performance-critical path can have clean logic. Looks good to me, and I'm a big fan of getting rid of the copy_mc bits on the generic iov iterator side: Reviewed-by: Jens Axboe -- Jens Axboe