linux/block, branch v5.6

block: Fix partition support for host aware zoned block devices

2020-03-12T13:54:39Z

Commit b72053072c0b ("block: allow partitions on host aware zone devices") introduced the helper function disk_has_partitions() to check if a given disk has valid partitions. However, since this function result directly depends on the disk partition table length rather than the actual existence of valid partitions in the table, it returns true even after all partitions are removed from the disk. For host aware zoned block devices, this results in zone management support to be kept disabled even after removing all partitions. Fix this by changing disk_has_partitions() to walk through the partition table entries and return true if and only if a valid non-zero size partition is found. Fixes: b72053072c0b ("block: allow partitions on host aware zone devices") Cc: stable@vger.kernel.org # 5.5 Reviewed-by: Damien Le Moal Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Shin'ichiro Kawasaki Signed-off-by: Jens Axboe

blk-mq: insert flush request to the front of dispatch queue

2020-03-12T13:26:12Z

commit 01e99aeca397 ("blk-mq: insert passthrough request into hctx->dispatch directly") may change to add flush request to the tail of dispatch by applying the 'add_head' parameter of blk_mq_sched_insert_request. Turns out this way causes performance regression on NCQ controller because flush is non-NCQ command, which can't be queued when there is any in-flight NCQ command. When adding flush rq to the front of hctx->dispatch, it is easier to introduce extra time to flush rq's latency compared with adding to the tail of dispatch queue because of S_SCHED_RESTART, then chance of flush merge is increased, and less flush requests may be issued to controller. So always insert flush request to the front of dispatch queue just like before applying commit 01e99aeca397 ("blk-mq: insert passthrough request into hctx->dispatch directly"). Cc: Damien Le Moal Cc: Shinichiro Kawasaki Reported-by: Shinichiro Kawasaki Fixes: 01e99aeca397 ("blk-mq: insert passthrough request into hctx->dispatch directly") Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

blk-iocost: fix incorrect vtime comparison in iocg_is_idle()

2020-03-10T17:37:00Z

vtimes may wrap and time_before/after64() should be used to determine whether a given vtime is before or after another. iocg_is_idle() was incorrectly using plain "<" comparison do determine whether done_vtime is before vtime. Here, the only thing we're interested in is whether done_vtime matches vtime which indicates that there's nothing in flight. Let's test for inequality instead. Signed-off-by: Tejun Heo Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Jens Axboe

block, bfq: fix overwrite of bfq_group pointer in bfq_find_set_group()

2020-03-06T14:00:58Z

The bfq_find_set_group() function takes as input a blkcg (which represents a cgroup) and retrieves the corresponding bfq_group, then it updates the bfq internal group hierarchy (see comments inside the function for why this is needed) and finally it returns the bfq_group. In the hierarchy update cycle, the pointer holding the correct bfq_group that has to be returned is mistakenly used to traverse the hierarchy bottom to top, meaning that in each iteration it gets overwritten with the parent of the current group. Since the update cycle stops at root's children (depth = 2), the overwrite becomes a problem only if the blkcg describes a cgroup at a hierarchy level deeper than that (depth > 2). In this case the root's child that happens to be also an ancestor of the correct bfq_group is returned. The main consequence is that processes contained in a cgroup at depth greater than 2 are wrongly placed in the group described above by BFQ. This commits fixes this problem by using a different bfq_group pointer in the update cycle in order to avoid the overwrite of the variable holding the original group reference. Reported-by: Kwon Je Oh Signed-off-by: Carlo Nonato Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block: Remove used kblockd_schedule_work_on()

2020-03-02T14:17:31Z

Commit ee63cfa7fc19 ("block: add kblockd_schedule_work_on()") introduced the helper in 2016. Remove it because since then no caller was added. Cc: Jens Axboe Signed-off-by: Daniel Wagner Signed-off-by: Jens Axboe

blk-mq: Remove some unused function arguments

2020-02-26T17:34:41Z

The struct blk_mq_hw_ctx pointer argument in blk_mq_put_tag(), blk_mq_poll_nsecs(), and blk_mq_poll_hybrid_sleep() is unused, so remove it. Overall obj code size shows a minor reduction, before: text data bss dec hex filename 27306 1312 0 28618 6fca block/blk-mq.o 4303 272 0 4575 11df block/blk-mq-tag.o after: 27282 1312 0 28594 6fb2 block/blk-mq.o 4311 272 0 4583 11e7 block/blk-mq-tag.o Reviewed-by: Johannes Thumshirn Reviewed-by: Hannes Reinecke Signed-off-by: John Garry -- This minor patch had been carried as part of the blk-mq shared tags RFC, I'd rather not carry it anymore as it required rebasing, so now or never.. Signed-off-by: Jens Axboe

blk-mq: insert passthrough request into hctx->dispatch directly

2020-02-25T01:50:48Z

For some reason, device may be in one situation which can't handle FS request, so STS_RESOURCE is always returned and the FS request will be added to hctx->dispatch. However passthrough request may be required at that time for fixing the problem. If passthrough request is added to scheduler queue, there isn't any chance for blk-mq to dispatch it given we prioritize requests in hctx->dispatch. Then the FS IO request may never be completed, and IO hang is caused. So passthrough request has to be added to hctx->dispatch directly for fixing the IO hang. Fix this issue by inserting passthrough request into hctx->dispatch directly together withing adding FS request to the tail of hctx->dispatch in blk_mq_dispatch_rq_list(). Actually we add FS request to tail of hctx->dispatch at default, see blk_mq_request_bypass_insert(). Then it becomes consistent with original legacy IO request path, in which passthrough request is always added to q->queue_head. Cc: Dongli Zhang Cc: Christoph Hellwig Cc: Ewan D. Milne Signed-off-by: Ming Lei Signed-off-by: Jens Axboe

Merge tag 'block-5.6-2020-02-05' of git://git.kernel.dk/linux-block

2020-02-06T06:15:23Z

Pull more block updates from Jens Axboe: "Some later arrivals, but all fixes at this point: - bcache fix series (Coly) - Series of BFQ fixes (Paolo) - NVMe pull request from Keith with a few minor NVMe fixes - Various little tweaks" * tag 'block-5.6-2020-02-05' of git://git.kernel.dk/linux-block: (23 commits) nvmet: update AEN list and array at one place nvmet: Fix controller use after free nvmet: Fix error print message at nvmet_install_queue function brd: check and limit max_part par nvme-pci: remove nvmeq->tags nvmet: fix dsm failure when payload does not match sgl descriptor nvmet: Pass lockdep expression to RCU lists block, bfq: clarify the goal of bfq_split_bfqq() block, bfq: get a ref to a group when adding it to a service tree block, bfq: remove ifdefs from around gets/puts of bfq groups block, bfq: extend incomplete name of field on_st block, bfq: get extra ref to prevent a queue from being freed during a group move block, bfq: do not insert oom queue into position tree block, bfq: do not plug I/O for bfq_queues with no proc refs bcache: check return value of prio_read() bcache: fix incorrect data type usage in btree_flush_write() bcache: add readahead cache policy options via sysfs interface bcache: explicity type cast in bset_bkey_last() bcache: fix memory corruption in bch_cache_accounting_clear() xen/blkfront: limit allocated memory size to actual use case ...

block, bfq: clarify the goal of bfq_split_bfqq()

2020-02-03T13:58:15Z

The exact, general goal of the function bfq_split_bfqq() is not that apparent. Add a comment to make it clear. Tested-by: Oleksandr Natalenko Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe

block, bfq: get a ref to a group when adding it to a service tree

2020-02-03T13:58:15Z

BFQ schedules generic entities, which may represent either bfq_queues or groups of bfq_queues. When an entity is inserted into a service tree, a reference must be taken, to make sure that the entity does not disappear while still referred in the tree. Unfortunately, such a reference is mistakenly taken only if the entity represents a bfq_queue. This commit takes a reference also in case the entity represents a group. Tested-by: Oleksandr Natalenko Tested-by: Chris Evich Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe