linux/block, branch v5.2

blk-mq: fix up placement of debugfs directory of queue files

2019-07-06T16:07:38Z

When the blk-mq debugfs file creation logic was "cleaned up" it was cleaned up too much, causing the queue file to not be created in the correct location. Turns out the check for the directory being present is needed as if that has not happened yet, the files should not be created, and the function will be called later on in the initialization code so that the files can be created in the correct location. Fixes: 6cfc0081b046 ("blk-mq: no need to check return value of debugfs_create functions") Reported-by: Stephen Rothwell Cc: linux-block@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Jens Axboe

block, bfq: fix operator in BFQQ_TOTALLY_SEEKY

2019-06-25T17:38:08Z

By mistake, there is a '&' instead of a '==' in the definition of the macro BFQQ_TOTALLY_SEEKY. This commit replaces the wrong operator with the correct one. Fixes: 7074f076ff15 ("block, bfq: do not tag totally seeky queues as soft rt") Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block: fix page leak when merging to same page

2019-06-17T15:33:04Z

When multiple iovecs reference the same page, each get_user_page call will add a reference to the page. But once we've created the bio that information gets lost and only a single reference will be dropped after I/O completion. Use the same_page information returned from __bio_try_merge_page to drop additional references to pages that were already present in the bio. Based on a patch from Ming Lei. Link: https://lkml.org/lkml/2019/4/23/64 Fixes: 576ed913 ("block: use bio_add_page in bio_iov_iter_get_pages") Reported-by: David Gibson Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe

block: return from __bio_try_merge_page if merging occured in the same page

2019-06-17T15:33:02Z

We currently have an input same_page parameter to __bio_try_merge_page to prohibit merging in the same page. The rationale for that is that some callers need to account for every page added to a bio. Instead of letting these callers call twice into the merge code to account for the new vs existing page cases, just turn the paramter into an output one that returns if a merge in the same page occured and let them act accordingly. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe

blk-mq: remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests

2019-06-13T09:05:58Z

blk_mq_sched_free_requests() may be called in failure path in which q->elevator may not be setup yet, so remove WARN_ON(!q->elevator) from blk_mq_sched_free_requests for avoiding the false positive. This function is actually safe to call in case of !q->elevator because hctx->sched_tags is checked. Cc: Bart Van Assche Cc: Christoph Hellwig Cc: Yi Zhang Fixes: c3e2219216c9 ("block: free sched's request pool in blk_cleanup_queue") Reported-by: syzbot+b9d0d56867048c7bcfde@syzkaller.appspotmail.com Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

blk-mq: no need to check return value of debugfs_create functions

2019-06-13T09:00:30Z

When calling debugfs functions, there is no need to ever check the return value. The function can work or not, but the code logic should never do something different based on this. When all of these checks are cleaned up, lots of the functions used in the blk-mq-debugfs code can now return void, as no need to check the return value of them either. Overall, this ends up cleaning up the code and making it smaller, always a nice win. Cc: Jens Axboe Cc: linux-block@vger.kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Jens Axboe

block: force select mq-deadline for zoned block devices

2019-06-13T09:00:31Z

In most use cases of zoned block devices (aka SMR disks), the mq-deadline scheduler is mandatory as it implements sequential write command processing guarantees with zone write locking. So make sure that this scheduler is always enabled if CONFIG_BLK_DEV_ZONED is selected. Tested-by: Chaitanya Kulkarni Reviewed-by: Chaitanya Kulkarni Signed-off-by: Damien Le Moal Reviewed-by: Ming Lei Signed-off-by: Jens Axboe

cgroup/bfq: revert bfq.weight symlink change

2019-06-10T09:35:41Z

There's some discussion on how to do this the best, and Tejun prefers that BFQ just create the file itself instead of having cgroups support a symlink feature. Hence revert commit 54b7b868e826 and 19e9da9e86c4 for 5.2, and this can be done properly for 5.3. Signed-off-by: Jens Axboe

block, bfq: add weight symlink to the bfq.weight cgroup parameter

2019-06-07T07:29:40Z

Many userspace tools and services use the proportional-share policy of the blkio/io cgroups controller. The CFQ I/O scheduler implemented this policy for the legacy block layer. To modify the weight of a group in case CFQ was in charge, the 'weight' parameter of the group must be modified. On the other hand, the BFQ I/O scheduler implements the same policy in blk-mq, but, with BFQ, the parameter to modify has a different name: bfq.weight (forced choice until legacy block was present, because two different policies cannot share a common parameter in cgroups). Due to CFQ legacy, most if not all userspace configurations still use the parameter 'weight', and for the moment do not seem likely to be changed. But, when CFQ went away with legacy block, such a parameter ceased to exist. So, a simple workaround has been proposed [1] to make all configurations work: add a symlink, named weight, to bfq.weight. This commit adds such a symlink. [1] https://lkml.org/lkml/2019/4/8/555 Suggested-by: Johannes Thumshirn Signed-off-by: Angelo Ruocco Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block: free sched's request pool in blk_cleanup_queue

2019-06-07T04:39:39Z

In theory, IO scheduler belongs to request queue, and the request pool of sched tags belongs to the request queue too. However, the current tags allocation interfaces are re-used for both driver tags and sched tags, and driver tags is definitely host wide, and doesn't belong to any request queue, same with its request pool. So we need tagset instance for freeing request of sched tags. Meantime, blk_mq_free_tag_set() often follows blk_cleanup_queue() in case of non-BLK_MQ_F_TAG_SHARED, this way requires that request pool of sched tags to be freed before calling blk_mq_free_tag_set(). Commit 47cdee29ef9d94e ("block: move blk_exit_queue into __blk_release_queue") moves blk_exit_queue into __blk_release_queue for simplying the fast path in generic_make_request(), then causes oops during freeing requests of sched tags in __blk_release_queue(). Fix the above issue by move freeing request pool of sched tags into blk_cleanup_queue(), this way is safe becasue queue has been frozen and no any in-queue requests at that time. Freeing sched tags has to be kept in queue's release handler becasue there might be un-completed dispatch activity which might refer to sched tags. Cc: Bart Van Assche Cc: Christoph Hellwig Fixes: 47cdee29ef9d94e485eb08f962c74943023a5271 ("block: move blk_exit_queue into __blk_release_queue") Tested-by: Yi Zhang Reported-by: kernel test robot Signed-off-by: Ming Lei Signed-off-by: Jens Axboe