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Wed, 03 Mar 2021 06:58:01 -0500 X-MC-Unique: TJBI0qZ4NyqOBlPrUtkKrw-1 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R131e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04426; MF=jefflexu@linux.alibaba.com; NM=1; PH=DS; RN=8; SR=0; TI=SMTPD_---0UQGHkBm_1614772664 Received: from localhost(mailfrom:jefflexu@linux.alibaba.com fp:SMTPD_---0UQGHkBm_1614772664) by smtp.aliyun-inc.com(127.0.0.1); Wed, 03 Mar 2021 19:57:45 +0800 From: Jeffle Xu To: msnitzer@redhat.com, axboe@kernel.dk Date: Wed, 3 Mar 2021 19:57:32 +0800 Message-Id: <20210303115740.127001-5-jefflexu@linux.alibaba.com> In-Reply-To: <20210303115740.127001-1-jefflexu@linux.alibaba.com> References: <20210303115740.127001-1-jefflexu@linux.alibaba.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Mimecast-Bulk-Signature: yes X-Mimecast-Spam-Signature: bulk X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-loop: dm-devel@redhat.com X-Mailman-Approved-At: Thu, 04 Mar 2021 09:41:43 -0500 Cc: caspar@linux.alibaba.com, linux-block@vger.kernel.org, joseph.qi@linux.alibaba.com, dm-devel@redhat.com, mpatocka@redhat.com, io-uring@vger.kernel.org Subject: [dm-devel] [PATCH v5 04/12] block: add poll_capable method to support bio-based IO polling X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dm-devel-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com This method can be used to check if bio-based device supports IO polling or not. For mq devices, checking for hw queue in polling mode is adequate, while the sanity check shall be implementation specific for bio-based devices. For example, dm device needs to check if all underlying devices are capable of IO polling. Though bio-based device may have done the sanity check during the device initialization phase, cacheing the result of this sanity check (such as by cacheing in the queue_flags) may not work. Because for dm devices, users could change the state of the underlying devices through '/sys/block//io_poll', bypassing the dm device above. In this case, the cached result of the very beginning sanity check could be out-of-date. Thus the sanity check needs to be done every time 'io_poll' is to be modified. Signed-off-by: Jeffle Xu --- block/blk-sysfs.c | 14 +++++++++++--- include/linux/blkdev.h | 1 + 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 0f4f0c8a7825..367c1d9a55c6 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -426,9 +426,17 @@ static ssize_t queue_poll_store(struct request_queue *q, const char *page, unsigned long poll_on; ssize_t ret; - if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || - !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) - return -EINVAL; + if (queue_is_mq(q)) { + if (!q->tag_set || q->tag_set->nr_maps <= HCTX_TYPE_POLL || + !q->tag_set->map[HCTX_TYPE_POLL].nr_queues) + return -EINVAL; + } else { + struct gendisk *disk = queue_to_disk(q); + + if (!disk->fops->poll_capable || + !disk->fops->poll_capable(disk)) + return -EINVAL; + } ret = queue_var_store(&poll_on, page, count); if (ret < 0) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 9dc83c30e7bc..7df40792c032 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1867,6 +1867,7 @@ static inline void blk_ksm_unregister(struct request_queue *q) { } struct block_device_operations { blk_qc_t (*submit_bio) (struct bio *bio); int (*poll)(struct request_queue *q, blk_qc_t cookie); + bool (*poll_capable)(struct gendisk *disk); int (*open) (struct block_device *, fmode_t); void (*release) (struct gendisk *, fmode_t); int (*rw_page)(struct block_device *, sector_t, struct page *, unsigned int);