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Tue, 27 Apr 2021 00:46:55 +0000 (GMT) From: Changheun Lee To: bvanassche@acm.org Cc: axboe@kernel.dk, bgoncalv@redhat.com, hch@lst.de, jaegeuk@kernel.org, linux-block@vger.kernel.org, ming.lei@redhat.com, nanich.lee@samsung.com, yi.zhang@redhat.com Subject: Re: [PATCH v2] block: Improve limiting the bio size Date: Tue, 27 Apr 2021 09:28:57 +0900 Message-Id: <20210427002857.8038-1-nanich.lee@samsung.com> X-Mailer: git-send-email 2.29.0 In-Reply-To: <34286266-1c03-35bc-94e8-08bd0ac3400a@acm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrEJsWRmVeSWpSXmKPExsWy7bCmnu7/uPYEgy9LDCxW3+1ns9h1cT6j xbQPP5ktVq4+ymTxZP0sZou9t7QtDk1uZrK4dv8Mu8X1c9PYHDg9Ll/x9rh8ttRj06pONo/d NxvYPN7vu8rm0bdlFaPH501yAexROTYZqYkpqUUKqXnJ+SmZeem2St7B8c7xpmYGhrqGlhbm Sgp5ibmptkouPgG6bpk5QHcpKZQl5pQChQISi4uV9O1sivJLS1IVMvKLS2yVUgtScgoMDQr0 ihNzi0vz0vWS83OtDA0MjEyBKhNyMh5eesNWsIW9ov9nO2MD4y/WLkZODgkBE4nL+54C2Vwc QgI7GCVeb1vEDOF8YpS49PYklPOZUeJew0RmuJZpz6BadjFKHN+ygxGuasa5V4wgVWwCOhJ9 b2+xgdgiAmISl798AytiFljNKNF6cztYQljARmL5y13sIDaLgKrE3rn3wJp5BawkWjqns0Cs k5f4c78HbDWngLXEzXM7mSFqBCVOznwCVsMMVNO8dTbYrRICjRwS29v7od5zkeiZ/JURwhaW eHV8CzuELSXx+d1eNoiGbkaJ5rb5jBDOBEaJJc+XMUFUGUt8+vwZKMEBtEJTYv0ufYiwosTO 33MZITbzSbz72sMKUiIhwCvR0SYEUaIicablPjPMrudrd0JN9JBYd/YmNFD7GCUunOhimsCo MAvJQ7OQPDQLYfMCRuZVjGKpBcW56anFhgWGyLG8iRGcWLVMdzBOfPtB7xAjEwfjIUYJDmYl EV62Xa0JQrwpiZVVqUX58UWlOanFhxhNgcE9kVlKNDkfmNrzSuINTY2MjY0tTMzMzUyNlcR5 052rE4QE0hNLUrNTUwtSi2D6mDg4pRqYvJkXy31sj1ng3aP885HMjyUrZ0lPdb9x4ycn96ra +QbzV/G5L48w/5/454p28KUjD6++PhH4o+D5dFeVG7v02uq05Vi/RF5q3jtP6GGro8qie1cM b1z8vyj2mWXRy87lazat582MqfmX/P+Gyqrgf+K83k8bSnREHpVGdroqBTxsmHloporD36+a ATO3xT69oZc6lXXrXTvjm69Drjb9jo/bmpuTrMv2/cAxl5PfMlZLxrRNTp5us/Wjh3ty3IE7 AiEvHuznDWid2y3lNlvt5Km8r8XFbbN/BHV7feKMWTr780PFmRqyvBo/l8zi8f47qy2nwYrH cvMKM/P1N01Z96RMX9/gEzF7m/GN0Lp9mUosxRmJhlrMRcWJAEQTnZY1BAAA X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrBLMWRmVeSWpSXmKPExsWy7bCSnO7/uPYEg4adEhar7/azWey6OJ/R YtqHn8wWK1cfZbJ4sn4Ws8XeW9oWhyY3M1lcu3+G3eL6uWlsDpwel694e1w+W+qxaVUnm8fu mw1sHu/3XWXz6NuyitHj8ya5APYoLpuU1JzMstQifbsEroyHl96wFWxhr+j/2c7YwPiLtYuR k0NCwETi8rRnQDYXh5DADkaJ86v3sEEkpCSOn3gLlOAAsoUlDh8uhqj5yCjx8+EDsBo2AR2J vre3wGwRATGJy1++MYIUMQtsZZR4+28pI0hCWMBGYvnLXewgNouAqsTeuffA4rwCVhItndNZ IJbJS/y538MMYnMKWEvcPLcTzBYCqrnbM5MFol5Q4uTMJ2A2M1B989bZzBMYBWYhSc1CklrA yLSKUTK1oDg3PbfYsMAoL7Vcrzgxt7g0L10vOT93EyM48LW0djDuWfVB7xAjEwfjIUYJDmYl EV62Xa0JQrwpiZVVqUX58UWlOanFhxilOViUxHkvdJ2MFxJITyxJzU5NLUgtgskycXBKNTAF 7dZjX1XKdk99CeOHhvu7pRiqtkdfjBLYq9nKa/bxVczFwx/6LkVPTM9MZZbQS3e9wRm8L3PD lkur5+xc4RllNiuC+6Dhtj2NUUVs17Y9L7XeOSdpi4J+dmHx9m//mNmlYu/fcp91LeBmMEPg 68UHz+vG7ZQ+tet59opTn+xaiyfyLTA/dvJPd/qnpZmcszrNjU8++swYVnGj34r3WOLCxqIX THMez28vbjuS2rPwyyf2rl3Nfwqn2bhptmav3vTosk5dhX1wQdKBX+1pNwr3yE7jqWL4m/5B bRq76/mNB2ZY2yVfkJre1VVWejLfmTNf/MrjQ2WW1auye2pdeSe+X5F3ZNmpVvnYbCe5M7uU WIozEg21mIuKEwEEC09X6wIAAA== X-CMS-MailID: 20210427004655epcas1p15cc4b2be6312c4762272474908607722 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20210427004655epcas1p15cc4b2be6312c4762272474908607722 References: <34286266-1c03-35bc-94e8-08bd0ac3400a@acm.org> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org > On 4/26/21 1:34 AM, Changheun Lee wrote: > > Should we check queue point in bio_max_size()? > > __device_add_disk() can be called with "register_queue=false" like as > > device_add_disk_no_queue_reg(). How about below? > > > > unsigned int bio_max_size(struct bio *bio) > > { > > struct request_queue *q; > > > > q = (bio->bi_bdev) ? bio->bi_bdev->bd_disk->queue : NULL; > > return q ? q->limits.bio_max_bytes : UINT_MAX; > > } > > How could bio_max_size() get called from inside __device_add_disk() if > no request queue is registered? Did I perhaps miss something? > > Thanks, > > Bart. __device_add_disk() do not call bio_max_size(). I just imagined bio operation on disk without request queue. Disk can be added without queue via device_add_disk_no_queue_reg(). It might be my miss-understood about it. I didn't check bio operation is possible on disk without request queue yet. Thanks, Changheun Lee.