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* fs: move guard_bio_eod() after bio_set_op_attrsMing Lei2020-01-091-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | Commit 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod") adds bio_truncate() for handling bio EOD. However, bio_truncate() doesn't use the passed 'op' parameter from guard_bio_eod's callers. So bio_trunacate() may retrieve wrong 'op', and zering pages may not be done for READ bio. Fixes this issue by moving guard_bio_eod() after bio_set_op_attrs() in submit_bh_wbc() so that bio_truncate() can always retrieve correct op info. Meantime remove the 'op' parameter from guard_bio_eod() because it isn't used any more. Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: linux-fsdevel@vger.kernel.org Fixes: 85a8ce62c2ea ("block: add bio_truncate to fix guard_bio_eod") Signed-off-by: Ming Lei <ming.lei@redhat.com> Fold in kerneldoc and bio_op() change. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix splitting segments on boundary masksMing Lei2019-12-301-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We ran into a problem with a mpt3sas based controller, where we would see random (and hard to reproduce) file corruption). The issue seemed specific to this controller, but wasn't specific to the file system. After a lot of debugging, we find out that it's caused by segments spanning a 4G memory boundary. This shouldn't happen, as the default setting for segment boundary masks is 4G. Turns out there are two issues in get_max_segment_size(): 1) The default segment boundary mask is bypassed 2) The segment start address isn't taken into account when checking segment boundary limit Fix these two issues by removing the bypass of the segment boundary check even if the mask is set to the default value, and taking into account the actual start address of the request when checking if a segment needs splitting. Cc: stable@vger.kernel.org # v5.1+ Reviewed-by: Chris Mason <clm@fb.com> Tested-by: Chris Mason <clm@fb.com> Fixes: dcebd755926b ("block: use bio_for_each_bvec() to compute multi-page bvec count") Signed-off-by: Ming Lei <ming.lei@redhat.com> Dropped const on the page pointer, ppc page_to_phys() doesn't mark the page as const... Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: add bio_truncate to fix guard_bio_eodMing Lei2019-12-281-0/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some filesystem, such as vfat, may send bio which crosses device boundary, and the worse thing is that the IO request starting within device boundaries can contain more than one segment past EOD. Commit dce30ca9e3b6 ("fs: fix guard_bio_eod to check for real EOD errors") tries to fix this issue by returning -EIO for this situation. However, this way lets fs user code lose chance to handle -EIO, then sync_inodes_sb() may hang for ever. Also the current truncating on last segment is dangerous by updating the last bvec, given bvec table becomes not immutable any more, and fs bio users may not retrieve the truncated pages via bio_for_each_segment_all() in its .end_io callback. Fixes this issue by supporting multi-segment truncating. And the approach is simpler: - just update bio size since block layer can make correct bvec with the updated bio size. Then bvec table becomes really immutable. - zero all truncated segments for read bio Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: linux-fsdevel@vger.kernel.org Fixed-by: dce30ca9e3b6 ("fs: fix guard_bio_eod to check for real EOD errors") Reported-by: syzbot+2b9e54155c8c25d8d165@syzkaller.appspotmail.com Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* compat_ioctl: block: handle Persistent ReservationsArnd Bergmann2019-12-211-0/+9
| | | | | | | | | | | | | These were added to blkdev_ioctl() in linux-5.5 but not blkdev_compat_ioctl, so add them now. Cc: <stable@vger.kernel.org> # v4.4+ Fixes: bbd3e064362e ("block: add an API for Persistent Reservations") Signed-off-by: Arnd Bergmann <arnd@arndb.de> Fold in followup patch from Arnd with missing pr.h header include. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* compat_ioctl: block: handle add zone open, close and finish ioctlArnd Bergmann2019-12-211-0/+3
| | | | | | | | | | These were added to blkdev_ioctl() in linux-5.5 but not blkdev_compat_ioctl, so add them now. Fixes: e876df1fe0ad ("block: add zone open, close and finish ioctl support") Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* compat_ioctl: block: handle BLKGETZONESZ/BLKGETNRZONESArnd Bergmann2019-12-211-0/+2
| | | | | | | | | | | | These were added to blkdev_ioctl() in v4.20 but not blkdev_compat_ioctl, so add them now. Cc: <stable@vger.kernel.org> # v4.20+ Fixes: 72cd87576d1d ("block: Introduce BLKGETZONESZ ioctl") Fixes: 65e4e3eee83d ("block: Introduce BLKGETNRZONES ioctl") Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* compat_ioctl: block: handle BLKREPORTZONE/BLKRESETZONEArnd Bergmann2019-12-211-0/+2
| | | | | | | | | | | These were added to blkdev_ioctl() but not blkdev_compat_ioctl, so add them now. Cc: <stable@vger.kernel.org> # v4.10+ Fixes: 3ed05a987e0f ("blk-zoned: implement ioctls") Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: fix memleak when __blk_rq_map_user_iov() is failedYang Yingliang2019-12-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When I doing fuzzy test, get the memleak report: BUG: memory leak unreferenced object 0xffff88837af80000 (size 4096): comm "memleak", pid 3557, jiffies 4294817681 (age 112.499s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 20 00 00 00 10 01 00 00 00 00 00 00 01 00 00 00 ............... backtrace: [<000000001c894df8>] bio_alloc_bioset+0x393/0x590 [<000000008b139a3c>] bio_copy_user_iov+0x300/0xcd0 [<00000000a998bd8c>] blk_rq_map_user_iov+0x2f1/0x5f0 [<000000005ceb7f05>] blk_rq_map_user+0xf2/0x160 [<000000006454da92>] sg_common_write.isra.21+0x1094/0x1870 [<00000000064bb208>] sg_write.part.25+0x5d9/0x950 [<000000004fc670f6>] sg_write+0x5f/0x8c [<00000000b0d05c7b>] __vfs_write+0x7c/0x100 [<000000008e177714>] vfs_write+0x1c3/0x500 [<0000000087d23f34>] ksys_write+0xf9/0x200 [<000000002c8dbc9d>] do_syscall_64+0x9f/0x4f0 [<00000000678d8e9a>] entry_SYSCALL_64_after_hwframe+0x49/0xbe If __blk_rq_map_user_iov() is failed in blk_rq_map_user_iov(), the bio(s) which is allocated before this failing will leak. The refcount of the bio(s) is init to 1 and increased to 2 by calling bio_get(), but __blk_rq_unmap_user() only decrease it to 1, so the bio cannot be freed. Fix it by calling blk_rq_unmap_user(). Reviewed-by: Bob Liu <bob.liu@oracle.com> Reported-by: Hulk Robot <hulkci@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix a lockdep complaint triggered by request queue flushingBart Van Assche2019-12-202-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid that running test nvme/012 from the blktests suite triggers the following false positive lockdep complaint: ============================================ WARNING: possible recursive locking detected 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Not tainted -------------------------------------------- ksoftirqd/1/16 is trying to acquire lock: 000000000282032e (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 but task is already holding lock: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&fq->mq_flush_lock)->rlock); lock(&(&fq->mq_flush_lock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by ksoftirqd/1/16: #0: 00000000cbadcbc2 (&(&fq->mq_flush_lock)->rlock){..-.}, at: flush_end_io+0x4e/0x1d0 stack backtrace: CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.0.0-rc3-xfstests-00015-g1236f7d60242 #841 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: dump_stack+0x67/0x90 __lock_acquire.cold.45+0x2b4/0x313 lock_acquire+0x98/0x160 _raw_spin_lock_irqsave+0x3b/0x80 flush_end_io+0x4e/0x1d0 blk_mq_complete_request+0x76/0x110 nvmet_req_complete+0x15/0x110 [nvmet] nvmet_bio_done+0x27/0x50 [nvmet] blk_update_request+0xd7/0x2d0 blk_mq_end_request+0x1a/0x100 blk_flush_complete_seq+0xe5/0x350 flush_end_io+0x12f/0x1d0 blk_done_softirq+0x9f/0xd0 __do_softirq+0xca/0x440 run_ksoftirqd+0x24/0x50 smpboot_thread_fn+0x113/0x1e0 kthread+0x121/0x140 ret_from_fork+0x3a/0x50 Cc: Christoph Hellwig <hch@infradead.org> Cc: Ming Lei <ming.lei@redhat.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: Fix the type of 'sts' in bsg_queue_rq()Bart Van Assche2019-12-201-1/+1
| | | | | | | | | | | | | | | | This patch fixes the following sparse warnings: block/bsg-lib.c:269:19: warning: incorrect type in initializer (different base types) block/bsg-lib.c:269:19: expected int sts block/bsg-lib.c:269:19: got restricted blk_status_t [usertype] block/bsg-lib.c:286:16: warning: incorrect type in return expression (different base types) block/bsg-lib.c:286:16: expected restricted blk_status_t block/bsg-lib.c:286:16: got int [assigned] sts Cc: Martin Wilck <mwilck@suse.com> Fixes: d46fe2cb2dce ("block: drop device references in bsg_queue_rq()") Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAITRoman Penyaev2019-12-171-4/+7
| | | | | | | | | | | | | | | | | | | Non-mq devs do not honor REQ_NOWAIT so give a chance to the caller to repeat request gracefully on -EAGAIN error. The problem is well reproduced using io_uring: mkfs.ext4 /dev/ram0 mount /dev/ram0 /mnt # Preallocate a file dd if=/dev/zero of=/mnt/file bs=1M count=1 # Start fio with io_uring and get -EIO fio --rw=write --ioengine=io_uring --size=1M --direct=1 --name=job --filename=/mnt/file Signed-off-by: Roman Penyaev <rpenyaev@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* iocost: over-budget forced IOs should schedule async delayTejun Heo2019-12-161-5/+8
| | | | | | | | | | | | | | | | | | | When over-budget IOs are force-issued through root cgroup, iocg_kick_delay() adjusts the async delay accordingly but doesn't actually schedule async throttle for the issuing task. This bug is pretty well masked because sooner or later the offending threads are gonna get directly throttled on regular IOs or have async delay scheduled by mem_cgroup_throttle_swaprate(). However, it can affect control quality on filesystem metadata heavy operations. Let's fix it by invoking blkcg_schedule_throttle() when iocg_kick_delay() says async delay is needed. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org Reported-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'for-linus-20191212' of git://git.kernel.dk/linux-blockLinus Torvalds2019-12-133-23/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull block fixes from Jens Axboe: - stable fix for the bi_size overflow. Not a corruption issue, but a case wher we could merge but disallowed (Andreas) - NVMe pull request via Keith, with various fixes. - MD pull request from Song. - Merge window regression fix for the rq passthrough stats (Logan) - Remove unused blkcg_drain_queue() function (Guoqing) * tag 'for-linus-20191212' of git://git.kernel.dk/linux-block: blk-cgroup: remove blkcg_drain_queue block: fix NULL pointer dereference in account statistics with IDE md: make sure desc_nr less than MD_SB_DISKS md: raid1: check rdev before reference in raid1_sync_request func raid5: need to set STRIPE_HANDLE for batch head block: fix "check bi_size overflow before merge" nvme/pci: Fix read queue count nvme/pci Limit write queue sizes to possible cpus nvme/pci: Fix write and poll queue types nvme/pci: Remove last_cq_head nvme: Namepace identification descriptor list is optional nvme-fc: fix double-free scenarios on hw queues nvme: else following return is not needed nvme: add error message on mismatching controller ids nvme_fc: add module to ops template to allow module references nvmet-loop: Avoid preallocating big SGL for data nvme-fc: Avoid preallocating big SGL for data nvme-rdma: Avoid preallocating big SGL for data
| * blk-cgroup: remove blkcg_drain_queueGuoqing Jiang2019-12-121-20/+0
| | | | | | | | | | | | | | | | Since blk_drain_queue had already been removed, so this function is not needed anymore. Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: fix NULL pointer dereference in account statistics with IDELogan Gunthorpe2019-12-121-2/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The IDE driver creates some passthru requests which never get submitted to the block layer in such a way that blk_account_io_start() gets called. However, the driver still calls __blk_mq_end_request() in ide_end_rq() which will call blk_account_io_completion() which tries to dereferences req->part which is never set. See ide_prep_sense() for an example of where these requests come from. To fix this, blk_account_io_completion() and blk_account_io_done() should do nothing if req->part is not set. The back trace of this bug is: BUG: kernel NULL pointer dereference, address: 000002ac #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 00000000 Oops: 0002 [#1] CPU: 0 PID: 237 Comm: kworker/0:1H Not tainted 5.4.0-rc2-00011-g48d9b0d43105e #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 Workqueue: kblockd drive_rq_insert_work EIP: blk_account_io_completion+0x7a/0xf0 Code: 89 54 24 08 31 d2 89 4c 24 04 31 c9 c7 04 24 02 00 00 00 c1 ee 09 e8 f5 21 a6 ff e8 70 5c a7 ff 8b 53 60 8d 04 bd 00 00 00 00 <01> b4 02 ac 02 00 00 8b 9a 88 02 00 00 85 db 74 11 85 d2 74 51 8b EAX: 00000000 EBX: f5b80000 ECX: 00000000 EDX: 00000000 ESI: 00000000 EDI: 00000000 EBP: f3031e70 ESP: f3031e54 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010046 CR0: 80050033 CR2: 000002ac CR3: 03c25000 CR4: 000406d0 Call Trace: <IRQ> blk_update_request+0x85/0x420 ide_end_rq+0x38/0xa0 ide_complete_rq+0x3d/0x70 cdrom_newpc_intr+0x258/0xba0 ide_intr+0x135/0x250 __handle_irq_event_percpu+0x3e/0x250 handle_irq_event_percpu+0x1f/0x50 handle_irq_event+0x32/0x60 handle_level_irq+0x6c/0x110 handle_irq+0x72/0xa0 </IRQ> do_IRQ+0x45/0xad common_interrupt+0x115/0x11c Fixes: 48d9b0d43105 ("block: account statistics for passthrough requests") Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * block: fix "check bi_size overflow before merge"Andreas Gruenbacher2019-12-091-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This partially reverts commit e3a5d8e386c3fb973fa75f2403622a8f3640ec06. Commit e3a5d8e386c3 ("check bi_size overflow before merge") adds a bio_full check to __bio_try_merge_page. This will cause __bio_try_merge_page to fail when the last bi_io_vec has been reached. Instead, what we want here is only the bi_size overflow check. Fixes: e3a5d8e386c3 ("block: check bi_size overflow before merge") Cc: stable@vger.kernel.org # v5.4+ Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | treewide: Use sizeof_field() macroPankaj Bharadiya2019-12-091-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | Replace all the occurrences of FIELD_SIZEOF() with sizeof_field() except at places where these are defined. Later patches will remove the unused definition of FIELD_SIZEOF(). This patch is generated using following script: EXCLUDE_FILES="include/linux/stddef.h|include/linux/kernel.h" git grep -l -e "\bFIELD_SIZEOF\b" | while read file; do if [[ "$file" =~ $EXCLUDE_FILES ]]; then continue fi sed -i -e 's/\bFIELD_SIZEOF\b/sizeof_field/g' $file; done Signed-off-by: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com> Link: https://lore.kernel.org/r/20190924105839.110713-3-pankaj.laxminarayan.bharadiya@intel.com Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: David Miller <davem@davemloft.net> # for net
* block: fix memleak of bio integrity dataJustin Tee2019-12-053-1/+8
| | | | | | | | | | | | | | | | | | | | | | 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") moves bio_integrity_free from bio_uninit() to bio_integrity_verify_fn() and bio_endio(). This way looks wrong because bio may be freed without calling bio_endio(), for example, blk_rq_unprep_clone() is called from dm_mq_queue_rq() when the underlying queue of dm-mpath is busy. So memory leak of bio integrity data is caused by commit 7c20f11680a4. Fixes this issue by re-adding bio_integrity_free() to bio_uninit(). Fixes: 7c20f11680a4 ("bio-integrity: stop abusing bi_end_io") Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by Justin Tee <justin.tee@broadcom.com> Add commit log, and simplify/fix the original patch wroten by Justin. Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* bfq-iosched: Ensure bio->bi_blkg is valid before using itHou Tao2019-12-051-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | bio->bi_blkg will be NULL when the issue of the request has bypassed the block layer as shown in the following oops: Internal error: Oops: 96000005 [#1] SMP CPU: 17 PID: 2996 Comm: scsi_id Not tainted 5.4.0 #4 Call trace: percpu_counter_add_batch+0x38/0x4c8 bfqg_stats_update_legacy_io+0x9c/0x280 bfq_insert_requests+0xbac/0x2190 blk_mq_sched_insert_request+0x288/0x670 blk_execute_rq_nowait+0x140/0x178 blk_execute_rq+0x8c/0x140 sg_io+0x604/0x9c0 scsi_cmd_ioctl+0xe38/0x10a8 scsi_cmd_blk_ioctl+0xac/0xe8 sd_ioctl+0xe4/0x238 blkdev_ioctl+0x590/0x20e0 block_ioctl+0x60/0x98 do_vfs_ioctl+0xe0/0x1b58 ksys_ioctl+0x80/0xd8 __arm64_sys_ioctl+0x40/0x78 el0_svc_handler+0xc4/0x270 so ensure its validity before using it. Fixes: fd41e60331b1 ("bfq-iosched: stop using blkg->stat_bytes and ->stat_ios") Signed-off-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: set the zone size in blk_revalidate_disk_zones atomicallyChristoph Hellwig2019-12-031-26/+33
| | | | | | | | | | | | | | | | | | | | The current zone revalidation code has a major problem in that it doesn't update the zone size and q->nr_zones atomically, leading to a short window where an out of bounds access to the zone arrays is possible. To fix this move the setting of the zone size into the crticial sections blk_revalidate_disk_zones so that it gets updated together with the zone bitmaps and q->nr_zones. This also slightly simplifies the caller as it deducts the zone size from the report_zones. This change also allows to check for a power of two zone size in generic code. Reported-by: Hans Holmberg <hans@owltronix.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: don't handle bio based drivers in blk_revalidate_disk_zonesChristoph Hellwig2019-12-031-11/+5
| | | | | | | | | | | bio based drivers only need to update q->nr_zones. Do that manually instead of overloading blk_revalidate_disk_zones to keep that function simpler for the next round of changes that will rely even more on the request based functionality. Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: allocate the zone bitmaps lazilyChristoph Hellwig2019-12-031-33/+32
| | | | | | | | | | | Allocate the conventional zone bitmap and the sequential zone locking bitmap only when we find a zone of the respective type. This avoids wasting memory on the conventional zone bitmap for devices that only have sequential zones, and will also prepare for other future changes. Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: replace seq_zones_bitmap with conv_zones_bitmapChristoph Hellwig2019-12-031-9/+9
| | | | | | | | | | Invert the meaning of seq_zones_bitmap by keeping a bitmap of conventional zones. This allows not having a bitmap for devices that do not have conventional zones. Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: simplify blkdev_nr_zonesChristoph Hellwig2019-12-032-19/+9
| | | | | | | | | | Simplify the arguments to blkdev_nr_zones by passing a gendisk instead of the block_device and capacity. This also removes the need for __blkdev_nr_zones as all callers are outside the fast path and can deal with the additional branch. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* block: remove the empty line at the end of blk-zoned.cChristoph Hellwig2019-12-031-1/+0
| | | | | Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* Merge tag 'compat-ioctl-5.5' of ↵Linus Torvalds2019-12-011-4/+128
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground Pull removal of most of fs/compat_ioctl.c from Arnd Bergmann: "As part of the cleanup of some remaining y2038 issues, I came to fs/compat_ioctl.c, which still has a couple of commands that need support for time64_t. In completely unrelated work, I spent time on cleaning up parts of this file in the past, moving things out into drivers instead. After Al Viro reviewed an earlier version of this series and did a lot more of that cleanup, I decided to try to completely eliminate the rest of it and move it all into drivers. This series incorporates some of Al's work and many patches of my own, but in the end stops short of actually removing the last part, which is the scsi ioctl handlers. I have patches for those as well, but they need more testing or possibly a rewrite" * tag 'compat-ioctl-5.5' of git://git.kernel.org:/pub/scm/linux/kernel/git/arnd/playground: (42 commits) scsi: sd: enable compat ioctls for sed-opal pktcdvd: add compat_ioctl handler compat_ioctl: move SG_GET_REQUEST_TABLE handling compat_ioctl: ppp: move simple commands into ppp_generic.c compat_ioctl: handle PPPIOCGIDLE for 64-bit time_t compat_ioctl: move PPPIOCSCOMPRESS to ppp_generic compat_ioctl: unify copy-in of ppp filters tty: handle compat PPP ioctls compat_ioctl: move SIOCOUTQ out of compat_ioctl.c compat_ioctl: handle SIOCOUTQNSD af_unix: add compat_ioctl support compat_ioctl: reimplement SG_IO handling compat_ioctl: move WDIOC handling into wdt drivers fs: compat_ioctl: move FITRIM emulation into file systems gfs2: add compat_ioctl support compat_ioctl: remove unused convert_in_user macro compat_ioctl: remove last RAID handling code compat_ioctl: remove /dev/raw ioctl translation compat_ioctl: remove PCI ioctl translation compat_ioctl: remove joystick ioctl translation ...
| * compat_ioctl: reimplement SG_IO handlingArnd Bergmann2019-10-231-4/+128
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two code locations that implement the SG_IO ioctl: the old sg.c driver, and the generic scsi_ioctl helper that is in turn used by multiple drivers. To eradicate the old compat_ioctl conversion handler for the SG_IO command, I implement a readable pair of put_sg_io_hdr() /get_sg_io_hdr() helper functions that can be used for both compat and native mode, and then I call this from both drivers. For the iovec handling, there is already a compat_import_iovec() function that can simply be called in place of import_iovec(). To avoid having to pass the compat/native state through multiple indirections, I mark the SG_IO command itself as compatible in fs/compat_ioctl.c and use in_compat_syscall() to figure out where we are called from. As a side-effect of this, the sg.c driver now also accepts the 32-bit sg_io_hdr format in compat mode using the read/write interface, not just ioctl. This should improve compatiblity with old 32-bit binaries, but it would break if any application intentionally passes the 64-bit data structure in compat mode here. Steffen Maier helped debug an issue in an earlier version of this patch. Cc: Steffen Maier <maier@linux.ibm.com> Cc: linux-scsi@vger.kernel.org Cc: Doug Gilbert <dgilbert@interlog.com> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
* | Merge tag 'for-5.5/disk-revalidate-20191122' of git://git.kernel.dk/linux-blockLinus Torvalds2019-11-252-133/+84
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull disk revalidation updates from Jens Axboe: "This continues the work that Jan Kara started to thoroughly cleanup and consolidate how we handle rescans and revalidations" * tag 'for-5.5/disk-revalidate-20191122' of git://git.kernel.dk/linux-block: block: move clearing bd_invalidated into check_disk_size_change block: remove (__)blkdev_reread_part as an exported API block: fix bdev_disk_changed for non-partitioned devices block: move rescan_partitions to fs/block_dev.c block: merge invalidate_partitions into rescan_partitions block: refactor rescan_partitions
| * | block: remove (__)blkdev_reread_part as an exported APIChristoph Hellwig2019-11-141-30/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In general drivers should never mess with partition tables directly. Unfortunately s390 and loop do for somewhat historic reasons, but they can use bdev_disk_changed directly instead when we export it as they satisfy the sanity checks we have in __blkdev_reread_part. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Stefan Haberland <sth@linux.ibm.com> [dasd] Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: fix bdev_disk_changed for non-partitioned devicesChristoph Hellwig2019-11-142-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We still have to set the capacity to 0 if invalidating or call revalidate_disk if not even if the disk has no partitions. Fix that by merging rescan_partitions into bdev_disk_changed and just stubbing out blk_add_partitions and blk_drop_partitions for non-partitioned devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: move rescan_partitions to fs/block_dev.cChristoph Hellwig2019-11-141-35/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Large parts of rescan_partitions aren't about partitions, and moving it to block_dev.c will allow for some further cleanups by merging it into its only caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: merge invalidate_partitions into rescan_partitionsChristoph Hellwig2019-11-142-25/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A lot of the logic in invalidate_partitions and rescan_partitions is shared. Merge the two functions to simplify things. There is a small behavior change in that we now send the kevent change notice also if we were not invalidating but no partitions were found, which seems like the right thing to do. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: refactor rescan_partitionsChristoph Hellwig2019-11-141-78/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split out a helper that adds one single partition, and another one calling that dealing with the parsed_partitions state. This makes it much more obvious how we clean up all state and start again when using the rescan label. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | Merge tag 'for-5.5/zoned-20191122' of git://git.kernel.dk/linux-blockLinus Torvalds2019-11-253-280/+156
|\ \ \ | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull zoned block device update from Jens Axboe: "Enhancements and improvements to the zoned device support" * tag 'for-5.5/zoned-20191122' of git://git.kernel.dk/linux-block: scsi: sd_zbc: Remove set but not used variable 'buflen' block: rework zone reporting scsi: sd_zbc: Cleanup sd_zbc_alloc_report_buffer() null_blk: Add zone_nr_conv to features null_blk: clean up report zones null_blk: clean up the block device operations block: Remove partition support for zoned block devices block: Simplify report zones execution block: cleanup the !zoned case in blk_revalidate_disk_zones block: Enhance blk_revalidate_disk_zones()
| * | block: rework zone reportingChristoph Hellwig2019-11-121-156/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid the need to allocate a potentially large array of struct blk_zone in the block layer by switching the ->report_zones method interface to a callback model. Now the caller simply supplies a callback that is executed on each reported zone, and private data for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Remove partition support for zoned block devicesDamien Le Moal2019-11-123-121/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | No known partitioning tool supports zoned block devices, especially the host managed flavor with strong sequential write constraints. Furthermore, there are also no known user nor use cases for partitioned zoned block devices. This patch removes partition device creation for zoned block devices, which allows simplifying the processing of zone commands for zoned block devices. A warning is added if a partition table is found on the device. For report zones operations no zone sector information remapping is necessary anymore, simplifying the code. Of note is that remapping of zone reports for DM targets is still necessary as done by dm_remap_zone_report(). Similarly, remaping of a zone reset bio is not necessary anymore. Testing for the applicability of the zone reset all request also becomes simpler and only needs to check that the number of sectors of the requested zone range is equal to the disk capacity. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Simplify report zones executionDamien Le Moal2019-11-121-29/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | All kernel users of blkdev_report_zones() as well as applications use through ioctl(BLKZONEREPORT) expect to potentially get less zone descriptors than requested. As such, the use of the internal report zones command execution loop implemented by blk_report_zones() is not necessary and can even be harmful to performance by causing the execution of inefficient small zones report command to service the reminder of a requested zone array. This patch removes blk_report_zones(), simplifying the code. Also remove a now incorrect comment in dm_blk_report_zones(). Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Javier Gonzalez <javier@javigon.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: cleanup the !zoned case in blk_revalidate_disk_zonesChristoph Hellwig2019-11-121-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk_revalidate_disk_zones is never called for non-zoned devices. Just return early and warn instead of trying to handle this case. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: Enhance blk_revalidate_disk_zones()Damien Le Moal2019-11-121-2/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For ZBC and ZAC zoned devices, the scsi driver revalidation processing implemented by sd_revalidate_disk() includes a call to sd_zbc_read_zones() which executes a full disk zone report used to check that all zones of the disk are the same size. This processing is followed by a call to blk_revalidate_disk_zones(), used to initialize the device request queue zone bitmaps (zone type and zone write lock bitmaps). To do so, blk_revalidate_disk_zones() also executes a full device zone report to obtain zone types. As a result, the entire zoned block device revalidation process includes two full device zone report. By moving the zone size checks into blk_revalidate_disk_zones(), this process can be optimized to a single full device zone report, leading to shorter device scan and revalidation times. This patch implements this optimization, reducing the original full device zone report implemented in sd_zbc_check_zones() to a single, small, report zones command execution to obtain the size of the first zone of the device. Checks whether all zones of the device are the same size as the first zone size are moved to the generic blk_check_zone() function called from blk_revalidate_disk_zones(). This optimization also has the following benefits: 1) fewer memory allocations in the scsi layer during disk revalidation as the potentailly large buffer for zone report execution is not needed. 2) Implement zone checks in a generic manner, reducing the burden on device driver which only need to obtain the zone size and check that this size is a power of 2 number of LBAs. Any new type of zoned block device will benefit from this. Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | | Merge tag 'for-5.5/block-20191121' of git://git.kernel.dk/linux-blockLinus Torvalds2019-11-2531-516/+963
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull core block updates from Jens Axboe: "Due to more granular branches, this one is small and will be followed with other core branches that add specific features. I meant to just have a core and drivers branch, but external dependencies we ended up adding a few more that are also core. The changes are: - Fixes and improvements for the zoned device support (Ajay, Damien) - sed-opal table writing and datastore UID (Revanth) - blk-cgroup (and bfq) blk-cgroup stat fixes (Tejun) - Improvements to the block stats tracking (Pavel) - Fix for overruning sysfs buffer for large number of CPUs (Ming) - Optimization for small IO (Ming, Christoph) - Fix typo in RWH lifetime hint (Eugene) - Dead code removal and documentation (Bart) - Reduction in memory usage for queue and tag set (Bart) - Kerneldoc header documentation (André) - Device/partition revalidation fixes (Jan) - Stats tracking for flush requests (Konstantin) - Various other little fixes here and there (et al)" * tag 'for-5.5/block-20191121' of git://git.kernel.dk/linux-block: (48 commits) Revert "block: split bio if the only bvec's length is > SZ_4K" block: add iostat counters for flush requests block,bfq: Skip tracing hooks if possible block: sed-opal: Introduce SUM_SET_LIST parameter and append it using 'add_token_u64' blk-cgroup: cgroup_rstat_updated() shouldn't be called on cgroup1 block: Don't disable interrupts in trigger_softirq() sbitmap: Delete sbitmap_any_bit_clear() blk-mq: Delete blk_mq_has_free_tags() and blk_mq_can_queue() block: split bio if the only bvec's length is > SZ_4K block: still try to split bio if the bvec crosses pages blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT blk-cgroup: reimplement basic IO stats using cgroup rstat blk-cgroup: remove now unused blkg_print_stat_{bytes|ios}_recursive() blk-throtl: stop using blkg->stat_bytes and ->stat_ios bfq-iosched: stop using blkg->stat_bytes and ->stat_ios bfq-iosched: relocate bfqg_*rwstat*() helpers block: add zone open, close and finish ioctl support block: add zone open, close and finish operations block: Simplify REQ_OP_ZONE_RESET_ALL handling block: Remove REQ_OP_ZONE_RESET plugging ...
| * | | Revert "block: split bio if the only bvec's length is > SZ_4K"Jens Axboe2019-11-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We really don't need this, as the slow path will do the right thing anyway. This reverts commit 6952a7f8446ee85ea9d10ab87b64797a031eaae3. Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: add iostat counters for flush requestsKonstantin Khlebnikov2019-11-213-5/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Requests that triggers flushing volatile writeback cache to disk (barriers) have significant effect to overall performance. Block layer has sophisticated engine for combining several flush requests into one. But there is no statistics for actual flushes executed by disk. Requests which trigger flushes usually are barriers - zero-size writes. This patch adds two iostat counters into /sys/class/block/$dev/stat and /proc/diskstats - count of completed flush requests and their total time. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block,bfq: Skip tracing hooks if possibleDmitry Monakhov2019-11-201-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In most cases blk_tracing is not active, but bfq_log_bfqq macro generate pid_str unconditionally, which result in significant overhead. ## Test modprobe null_blk echo bfq > /sys/block/nullb0/queue/scheduler fio --name=t --ioengine=libaio --direct=1 --filename=/dev/nullb0 \ --runtime=30 --time_based=1 --rw=write --iodepth=128 --bs=4k # Results | | baseline | w/ patch | gain | | iops | 113.19K | 126.42K | +11% | Acked-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Dmitry Monakhov <dmonakhov@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: sed-opal: Introduce SUM_SET_LIST parameter and append it using ↵Revanth Rajashekar2019-11-182-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 'add_token_u64' In function 'activate_lsp', rather than hard-coding the short atom header(0x83), we need to let the function 'add_short_atom_header' append the header based on the parameter being appended. The parameter has been defined in Section 3.1.2.1 of https://trustedcomputinggroup.org/wp-content/uploads/TCG_Storage-Opal_Feature_Set_Single_User_Mode_v1-00_r1-00-Final.pdf Reviewed-by: Jon Derrick <jonathan.derrick@intel.com> Signed-off-by: Revanth Rajashekar <revanth.rajashekar@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | block: Don't disable interrupts in trigger_softirq()Sebastian Andrzej Siewior2019-11-181-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | trigger_softirq() is always invoked as a SMP-function call which is always invoked with disables interrupts. Don't disable interrupt in trigger_softirq() because interrupts are already disabled. Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | | blk-mq: Delete blk_mq_has_free_tags() and blk_mq_can_queue()John Garry2019-11-133-15/+0
| |/ / | | | | | | | | | | | | | | | | | | These functions are not referenced, so delete them. Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: split bio if the only bvec's length is > SZ_4KMing Lei2019-11-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 64K PAGE_SIZE is popular on ARM64 or other ARCHs, and 64K has been big enough to break some devices probably, so change the logic to split bio if the only bvec's length is > SZ_4K instead of PAGE_SIZE. Fixes: fa5322872187 (block: avoid blk_bio_segment_split for small I/O operations) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | block: still try to split bio if the bvec crosses pagesMing Lei2019-11-081-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some device may set segment boundary as PAGE_SIZE - 1. If the bvec crosses pages, and meantime its length is <= PAGE_SIZE, we still need to split the bvec into 2 segments. Fixes this issue by still splitting bio if the single bvec crosses pages. Reported-by: kernel test robot <lkp@intel.com> Fixes: fa5322872187 (block: avoid blk_bio_segment_split for small I/O operations) Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTATTejun Heo2019-11-078-97/+287
| | | | | | | | | | | | | | | | | | | | | | | | | | | blkg_rwstat is now only used by bfq-iosched and blk-throtl when on cgroup1. Let's move it into its own files and gate it behind a config option. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
| * | blk-cgroup: reimplement basic IO stats using cgroup rstatTejun Heo2019-11-071-25/+99
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | blk-cgroup has been using blkg_rwstat to track basic IO stats. Unfortunately, reading recursive stats scales badly as itinvolves walking all descendants. On systems with a huge number of cgroups (dead or alive), this can lead to substantial CPU cost when reading IO stats. This patch reimplements basic IO stats using cgroup rstat which uses more memory but makes recursive stat reading O(# descendants which have been active since last reading) instead of O(# descendants). * blk-cgroup core no longer uses sync/async stats. Introduce new stat enums - BLKG_IOSTAT_{READ|WRITE|DISCARD}. * Add blkg_iostat[_set] which encapsulates byte and io stats, last values for propagation delta calculation and u64_stats_sync for correctness on 32bit archs. * Update the new percpu stat counters directly and implement blkcg_rstat_flush() to implement propagation. * blkg_print_stat() can now bring the stats up to date by calling cgroup_rstat_flush() and print them instead of directly summing up all descendants. * It now allocates 96 bytes per cpu. It used to be 40 bytes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Dan Schatzberg <dschatzberg@fb.com> Cc: Daniel Xu <dlxu@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>