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[209.132.180.67]) by mx.google.com with ESMTP id j10-v6si19332943plg.499.2018.08.15.15.16.50; Wed, 15 Aug 2018 15:17:05 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727969AbeHPBJu (ORCPT + 99 others); Wed, 15 Aug 2018 21:09:50 -0400 Received: from vps-vb.mhejs.net ([37.28.154.113]:48372 "EHLO vps-vb.mhejs.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726957AbeHPBJu (ORCPT ); Wed, 15 Aug 2018 21:09:50 -0400 X-Greylist: delayed 1138 seconds by postgrey-1.27 at vger.kernel.org; Wed, 15 Aug 2018 21:09:48 EDT Received: by vps-vb.mhejs.net with esmtps (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.90_1) (envelope-from ) id 1fq3mY-0006Le-OS; Wed, 15 Aug 2018 23:56:46 +0200 To: Paolo Valente , Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel , Arianna Avanzini From: "Maciej S. Szmigiero" Subject: [PATCH] block, bfq: return nbytes and not zero from struct cftype .write() method Openpgp: preference=signencrypt Autocrypt: addr=mail@maciej.szmigiero.name; prefer-encrypt=mutual; keydata= xsFNBFpGusUBEADXUMM2t7y9sHhI79+2QUnDdpauIBjZDukPZArwD+sDlx5P+jxaZ13XjUQc 6oJdk+jpvKiyzlbKqlDtw/Y2Ob24tg1g/zvkHn8AVUwX+ZWWewSZ0vcwp7u/LvA+w2nJbIL1 N0/QUUdmxfkWTHhNqgkNX5hEmYqhwUPozFR0zblfD/6+XFR7VM9yT0fZPLqYLNOmGfqAXlxY m8nWmi+lxkd/PYqQQwOq6GQwxjRFEvSc09m/YPYo9hxh7a6s8hAP88YOf2PD8oBB1r5E7KGb Fv10Qss4CU/3zaiyRTExWwOJnTQdzSbtnM3S8/ZO/sL0FY/b4VLtlZzERAraxHdnPn8GgxYk oPtAqoyf52RkCabL9dsXPWYQjkwG8WEUPScHDy8Uoo6imQujshG23A99iPuXcWc/5ld9mIo/ Ee7kN50MOXwS4vCJSv0cMkVhh77CmGUv5++E/rPcbXPLTPeRVy6SHgdDhIj7elmx2Lgo0cyh uyxyBKSuzPvb61nh5EKAGL7kPqflNw7LJkInzHqKHDNu57rVuCHEx4yxcKNB4pdE2SgyPxs9 9W7Cz0q2Hd7Yu8GOXvMfQfrBiEV4q4PzidUtV6sLqVq0RMK7LEi0RiZpthwxz0IUFwRw2KS/ 9Kgs9LmOXYimodrV0pMxpVqcyTepmDSoWzyXNP2NL1+GuQtaTQARAQABzTBNYWNpZWogUy4g U3ptaWdpZXJvIDxtYWlsQG1hY2llai5zem1pZ2llcm8ubmFtZT7CwZQEEwEIAD4WIQRyeg1N 257Z9gOb7O+Ef143kM4JdwUCWka6xQIbAwUJA8JnAAULCQgHAgYVCgkICwIEFgIDAQIeAQIX gAAKCRCEf143kM4Jdx4+EACwi1bXraGxNwgFj+KI8T0Xar3fYdaOF7bb7cAHllBCPQkutjnx 8SkYxqGvSNbBhGtpL1TqAYLB1Jr+ElB8qWEV6bJrffbRmsiBPORAxMfu8FF+kVqCYZs3nbku XNzmzp6R/eii40S+XySiscmpsrVQvz7I+xIIYdC0OTUu0Vl3IHf718GBYSD+TodCazEdN96k p9uD9kWNCU1vnL7FzhqClhPYLjPCkotrWM4gBNDbRiEHv1zMXb0/jVIR/wcDIUv6SLhzDIQn Lhre8LyKwid+WQxq7ZF0H+0VnPf5q56990cEBeB4xSyI+tr47uNP2K1kmW1FPd5q6XlIlvh2 WxsG6RNphbo8lIE6sd7NWSY3wXu4/R1AGdn2mnXKMp2O9039ewY6IhoeodCKN39ZR9LNld2w Dp0MU39LukPZKkVtbMEOEi0R1LXQAY0TQO//0IlAehfbkkYv6IAuNDd/exnj59GtwRfsXaVR Nw7XR/8bCvwU4svyRqI4luSuEiXvM9rwDAXbRKmu+Pk5h+1AOV+KjKPWCkBEHaASOxuApouQ aPZw6HDJ3fdFmN+m+vNcRPzST30QxGrXlS5GgY6CJ10W9gt/IJrFGoGxGxYjj4WzO97Rg6Mq WMa7wMPPNcnX5Nc/b8HW67Jhs3trj0szq6FKhqBsACktOU4g/ksV8eEtnM7AzQRaRrwiAQwA xnVmJqeP9VUTISps+WbyYFYlMFfIurl7tzK74bc67KUBp+PHuDP9p4ZcJUGC3UZJP85/GlUV dE1NairYWEJQUB7bpogTuzMI825QXIB9z842HwWfP2RW5eDtJMeujzJeFaUpmeTG9snzaYxY N3r0TDKj5dZwSIThIMQpsmhH2zylkT0jH7kBPxb8IkCQ1c6wgKITwoHFjTIO0B75U7bBNSDp XUaUDvd6T3xd1Fz57ujAvKHrZfWtaNSGwLmUYQAcFvrKDGPB5Z3ggkiTtkmW3OCQbnIxGJJw /+HefYhB5/kCcpKUQ2RYcYgCZ0/WcES1xU5dnNe4i0a5gsOFSOYCpNCfTHttVxKxZZTQ/rxj XwTuToXmTI4Nehn96t25DHZ0t9L9UEJ0yxH2y8Av4rtf75K2yAXFZa8dHnQgCkyjA/gs0ujG wD+Gs7dYQxP4i+rLhwBWD3mawJxLxY0vGwkG7k7npqanlsWlATHpOdqBMUiAR22hs02FikAo iXNgWTy7ABEBAAHCwXwEGAEIACYWIQRyeg1N257Z9gOb7O+Ef143kM4JdwUCWka8IgIbDAUJ A8JnAAAKCRCEf143kM4Jd9nXD/9jstJU6L1MLyr/ydKOnY48pSlZYgII9rSnFyLUHzNcW2c/ qw9LPMlDcK13tiVRQgKT4W+RvsET/tZCQcap2OF3Z6vd1naTur7oJvgvVM5lVhUia2O60kEZ XNlMLFwLSmGXhaAXNBySpzN2xStSLCtbK58r7Vf9QS0mR0PGU2v68Cb8fFWcYu2Yzn3RXf0Y dIVWvaQG9whxZq5MdJm5dknfTcCG+MtmbP/DnpQpjAlgVmDgMgYTBW1W9etU36YW0pTqEYuv 6cmRgSAKEDaYHhFLTR1+lLJkp5fFo3Sjm7XqmXzfSv9JGJGMKzoFOMBoLYv+VFnMoLX5UJAs 0JyFqFY2YxGyLd4J103NI/ocqQeU0TVvOZGVkENPSxIESnbxPghsEC0MWEbGsvqA8FwvU7Xf GhZPYzTRf7CndDnezEA69EhwpZXKs4CvxbXo5PDTv0OWzVaAWqq8s8aTMJWWAhvobFozJ63z afYHkuEjMo0Xps3o3uvKg7coooH521nNsv4ci+KeBq3mgMCRAy0g/Ef+Ql7mt900RCBHu4tk tOhPc3J1ep/e2WAJ4ngUqJhilzyCJnzVJ4cT79VK/uPtlfUCZdUz+jTC88TmP1p5wlucS31k Thy/CV4cqDFB8yzEujTSiRzd7neG3sH0vcxBd69uvSxLZPLGID840k0v5sftPA== Message-ID: Date: Wed, 15 Aug 2018 23:56:45 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 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 The value that struct cftype .write() method returns is then directly returned to userspace as the value returned by write() syscall, so it should be the number of bytes actually written (or consumed) and not zero. Returning zero from write() syscall makes programs like /bin/echo or bash spin. Signed-off-by: Maciej S. Szmigiero Fixes: e21b7a0b9887 ("block, bfq: add full hierarchical scheduling and cgroups support") Cc: stable@vger.kernel.org --- block/bfq-cgroup.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c index a9e8633388f4..58c6efa9f9a9 100644 --- a/block/bfq-cgroup.c +++ b/block/bfq-cgroup.c @@ -913,7 +913,8 @@ static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, if (ret) return ret; - return bfq_io_set_weight_legacy(of_css(of), NULL, weight); + ret = bfq_io_set_weight_legacy(of_css(of), NULL, weight); + return ret ?: nbytes; } #ifdef CONFIG_DEBUG_BLK_CGROUP