linux/block
Mike Snitzer e9637415a9 block: fix blk_stack_limits() regression due to lcm() change
Linux 3.19 commit 69c953c ("lib/lcm.c: lcm(n,0)=lcm(0,n) is 0, not n")
caused blk_stack_limits() to not properly stack queue_limits for stacked
devices (e.g. DM).

Fix this regression by establishing lcm_not_zero() and switching
blk_stack_limits() over to using it.

DM uses blk_set_stacking_limits() to establish the initial top-level
queue_limits that are then built up based on underlying devices' limits
using blk_stack_limits().  In the case of optimal_io_size (io_opt)
blk_set_stacking_limits() establishes a default value of 0.  With commit
69c953c, lcm(0, n) is no longer n, which compromises proper stacking of
the underlying devices' io_opt.

Test:
$ modprobe scsi_debug dev_size_mb=10 num_tgts=1 opt_blks=1536
$ cat /sys/block/sde/queue/optimal_io_size
786432
$ dmsetup create node --table "0 100 linear /dev/sde 0"

Before this fix:
$ cat /sys/block/dm-5/queue/optimal_io_size
0

After this fix:
$ cat /sys/block/dm-5/queue/optimal_io_size
786432

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.19+
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-31 09:45:50 -06:00
..
partitions Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block 2015-02-12 14:13:23 -08:00
Kconfig block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
Kconfig.iosched blkcg: make CONFIG_BLK_CGROUP bool 2012-03-06 21:27:21 +01:00
Makefile block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
bio-integrity.c block: fix regression where bio_integrity_process uses wrong bio_vec iterator 2014-12-02 08:15:21 -07:00
bio.c block: rewrite and split __bio_copy_iov() 2015-02-05 09:30:44 -07:00
blk-cgroup.c blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-cgroup.h blkcg: remove blkcg->id 2014-09-08 09:55:37 -06:00
blk-core.c Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block 2015-02-12 14:13:23 -08:00
blk-exec.c blk-mq: avoid infinite recursion with the FUA flag 2014-09-22 11:55:19 -06:00
blk-flush.c blk-mq: support per-distpatch_queue flush machinery 2014-09-25 15:22:45 -06:00
blk-integrity.c block: Don't merge requests if integrity flags differ 2014-09-27 09:14:57 -06:00
blk-ioc.c block: Substitute rcu_access_pointer() for rcu_dereference_raw() 2014-02-18 12:21:26 -08:00
blk-iopoll.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-03 12:57:53 -07:00
blk-lib.c block: Quiesce zeroout wrapper 2015-02-05 10:14:54 -07:00
blk-map.c block: handle the null_mapped flag correctly in blk_rq_map_user_iov 2015-02-11 11:24:12 -07:00
blk-merge.c Fix bug in blk_rq_merge_ok 2015-03-20 08:50:41 -06:00
blk-mq-cpu.c blk-mq: add file comments and update copyright notices 2014-05-28 10:15:41 -06:00
blk-mq-cpumap.c blk-mq: Use all available hardware queues 2014-12-09 09:08:21 -07:00
blk-mq-sysfs.c Revert "blk-mq: fix hctx/ctx kobject use-after-free" 2015-01-29 08:30:49 -08:00
blk-mq-tag.c blkmq: Fix NULL pointer deref when all reserved tags in 2015-03-18 17:06:18 -06:00
blk-mq-tag.h blk-mq: add tag allocation policy 2015-01-23 14:18:00 -07:00
blk-mq.c blk-mq: fix use of incorrect goto label in blk_mq_init_queue error path 2015-03-13 08:22:32 -06:00
blk-mq.h blk-mq: release mq's kobjects in blk_release_queue() 2015-01-29 08:30:51 -08:00
blk-settings.c block: fix blk_stack_limits() regression due to lcm() change 2015-03-31 09:45:50 -06:00
blk-softirq.c block: fix regression with block enabled tagging 2014-04-09 21:54:06 -06:00
blk-sysfs.c blk-mq: release mq's kobjects in blk_release_queue() 2015-01-29 08:30:51 -08:00
blk-tag.c block: support different tag allocation policy 2015-01-23 14:15:46 -07:00
blk-throttle.c blk-throttle: check stats_cpu before reading it from sysfs 2015-02-20 22:11:58 -08:00
blk-timeout.c blk-mq: Allow requests to never expire 2015-01-08 08:59:01 -07:00
blk.h blk-mq: support per-distpatch_queue flush machinery 2014-09-25 15:22:45 -06:00
bounce.c mm: convert some level-less printks to pr_* 2014-06-06 16:08:18 -07:00
bsg-lib.c bsg: Remove unused function bsg_goose_queue() 2012-12-06 14:33:02 +01:00
bsg.c block: Simplify bsg complete all 2015-02-04 09:57:52 -07:00
cfq-iosched.c cfq-iosched: handle failure of cfq group allocation 2015-02-09 10:22:39 -07:00
cmdline-parser.c block: remove unrelated header files and export symbol 2014-01-21 20:18:26 -08:00
compat_ioctl.c block, bdi: an active gendisk always has a request_queue associated with it 2014-09-08 10:00:35 -06:00
deadline-iosched.c block: Stop abusing csd.list for fifo_time 2014-02-24 14:46:32 -08:00
elevator.c block / PM: Replace CONFIG_PM_RUNTIME with CONFIG_PM 2014-12-04 01:00:23 +01:00
genhd.c genhd: check for int overflow in disk_expand_part_tbl() 2014-11-19 13:09:07 -07:00
ioctl.c block: Add discard flag to blkdev_issue_zeroout() function 2015-01-21 10:41:46 -07:00
ioprio.c block: Fix computation of merged request priority 2014-10-31 08:30:43 -06:00
noop-iosched.c elevator: Fix a race in elevator switching 2013-07-03 13:25:24 +02:00
partition-generic.c block: Fix dev_t minor allocation lifetime 2014-09-03 15:01:02 -06:00
scsi_ioctl.c block: pass iov_iter to the BLOCK_PC mapping functions 2015-02-05 09:30:40 -07:00
t10-pi.c block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00