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2015-05-20block: replace trylock with mutex_lock in blkdev_reread_part()Ming Lei1-2/+7
The only possible problem of using mutex_lock() instead of trylock is about deadlock. If there aren't any locks held before calling blkdev_reread_part(), deadlock can't be caused by this conversion. If there are locks held before calling blkdev_reread_part(), and if these locks arn't required in open, close handler and I/O path, deadlock shouldn't be caused too. Both user space's ioctl(BLKRRPART) and md_setup_drive() from init/do_mounts_md.c belongs to the 1st case, so the conversion is safe for the two cases. For loop, the previous patches in this pathset has fixed the ABBA lock dependency, so the conversion is OK. For nbd, tx_lock is held when calling the function: - both open and release won't hold the lock - when blkdev_reread_part() is run, I/O thread has been stopped already, so tx_lock won't be acquired in I/O path at that time. - so the conversion won't cause deadlock for nbd For dasd, both dasd_open(), dasd_release() and request function don't acquire any mutex/semphone, so the conversion should be safe. Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Jarod Wilson <jarod@redhat.com> Acked-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-20block: export blkdev_reread_part() and __blkdev_reread_part()Jarod Wilson1-3/+25
This patch exports blkdev_reread_part() for block drivers, also introduce __blkdev_reread_part(). For some drivers, such as loop, reread of partitions can be run from the release path, and bd_mutex may already be held prior to calling ioctl_by_bdev(bdev, BLKRRPART, 0), so introduce __blkdev_reread_part for use in such cases. CC: Christoph Hellwig <hch@lst.de> CC: Jens Axboe <axboe@kernel.dk> CC: Tejun Heo <tj@kernel.org> CC: Alexander Viro <viro@zeniv.linux.org.uk> CC: Markus Pargmann <mpa@pengutronix.de> CC: Stefan Weinhuber <wein@de.ibm.com> CC: Stefan Haberland <stefan.haberland@de.ibm.com> CC: Sebastian Ott <sebott@linux.vnet.ibm.com> CC: Fabian Frederick <fabf@skynet.be> CC: Ming Lei <ming.lei@canonical.com> CC: David Herrmann <dh.herrmann@gmail.com> CC: Andrew Morton <akpm@linux-foundation.org> CC: Peter Zijlstra <peterz@infradead.org> CC: nbd-general@lists.sourceforge.net CC: linux-s390@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-19block: remove unused BIO_RW_BLOCK and BIO_EOF flagsChristoph Hellwig1-2/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-19block: remove BIO_EOPNOTSUPPChristoph Hellwig1-3/+0
Since the big barrier rewrite/removal in 2007 we never fail FLUSH or FUA requests, which means we can remove the magic BIO_EOPNOTSUPP flag to help propagating those to the buffer_head layer. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-19block: use an atomic_t for mq_freeze_depthChristoph Hellwig1-14/+10
lockdep gets unhappy about the not disabling irqs when using the queue_lock around it. Instead of trying to fix that up just switch to an atomic_t and get rid of the lock. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08blk-mq: make plug work for mutiple disks and queuesShaohua Li3-9/+23
Last patch makes plug work for multiple queue case. However it only works for single disk case, because it assumes only one request in the plug list. If a task is accessing multiple disks, eg MD/DM, the assumption is wrong. Let blk_attempt_plug_merge() record request from the same queue. V2: use NULL parameter in !mq case. Fix a bug. Add comments in blk_attempt_plug_merge to make it less (hopefully) confusion. Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08blk-mq: do limited block plug for multiple queue caseShaohua Li1-23/+59
plug is still helpful for workload with IO merge, but it can be harmful otherwise especially with multiple hardware queues, as there is (supposed) no lock contention in this case and plug can introduce latency. For multiple queues, we do limited plug, eg plug only if there is request merge. If a request doesn't have merge with following request, the requet will be dispatched immediately. V2: check blk_queue_nomerges() as suggested by Jeff. Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08blk-mq: avoid re-initialize request which is failed in direct dispatchShaohua Li1-0/+2
If we directly issue a request and it fails, we use blk_mq_merge_queue_io(). But we already assigned bio to a request in blk_mq_bio_to_request. blk_mq_merge_queue_io shouldn't run blk_mq_bio_to_request again. Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08blk-mq: fix plugging in blk_sq_make_requestJeff Moyer1-22/+14
The following appears in blk_sq_make_request: /* * If we have multiple hardware queues, just go directly to * one of those for sync IO. */ We clearly don't have multiple hardware queues, here! This comment was introduced with this commit 07068d5b8e (blk-mq: split make request handler for multi and single queue): We want slightly different behavior from them: - On single queue devices, we currently use the per-process plug for deferred IO and for merging. - On multi queue devices, we don't use the per-process plug, but we want to go straight to hardware for SYNC IO. The old code had this: use_plug = !is_flush_fua && ((q->nr_hw_queues == 1) || !is_sync); and that was converted to: use_plug = !is_flush_fua && !is_sync; which is not equivalent. For the single queue case, that second half of the && expression is always true. So, what I think was actually inteded follows (and this more closely matches what is done in blk_queue_bio). V2: delete the 'likely', which should not be a big deal Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-08blk: clean up plugShaohua Li1-12/+12
Current code looks like inner plug gets flushed with a blk_finish_plug(). Actually it's a nop. All requests/callbacks are added to current->plug, while only outmost plug is assigned to current->plug. So inner plug always has empty request/callback list, which makes blk_flush_plug_list() a nop. This tries to make the code more clear. Signed-off-by: Shaohua Li <shli@fb.com> Reviewed-by: Jeff Moyer <jmoyer@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05block: move PM request support to IDEChristoph Hellwig3-12/+1
This removes the request types and hacks from the block code and into the old IDE driver. There is a small amunt of code duplication due to this, but it's not too bad. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05bio: skip atomic inc/dec of ->bi_cnt for most use casesJens Axboe1-7/+11
Struct bio has a reference count that controls when it can be freed. Most uses cases is allocating the bio, which then returns with a single reference to it, doing IO, and then dropping that single reference. We can remove this atomic_dec_and_test() in the completion path, if nobody else is holding a reference to the bio. If someone does call bio_get() on the bio, then we flag the bio as now having valid count and that we must properly honor the reference count when it's being put. Tested-by: Robert Elliott <elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-05bio: skip atomic inc/dec of ->bi_remaining for non-chainsJens Axboe1-9/+29
Struct bio has an atomic ref count for chained bio's, and we use this to know when to end IO on the bio. However, most bio's are not chained, so we don't need to always introduce this atomic operation as part of ending IO. Add a helper to elevate the bi_remaining count, and flag the bio as now actually needing the decrement at end_io time. Rename the field to __bi_remaining to catch any current users of this doing the incrementing manually. For high IOPS workloads, this reduces the overhead of bio_endio() substantially. Tested-by: Robert Elliott <elliott@hp.com> Acked-by: Kent Overstreet <kent.overstreet@gmail.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-17blk-mq: fix iteration of busy bitmapJens Axboe1-3/+3
Commit 889fa31f00b2 was a bit too eager in reducing the loop count, so we ended up missing queues in some configurations. Ensure that our division rounds up, so that's not the case. Reported-by: Guenter Roeck <linux@roeck-us.net> Fixes: 889fa31f00b2 ("blk-mq: reduce unnecessary software queue looping") Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-17Merge branch 'for-4.1/core' of git://git.kernel.dk/linux-blockLinus Torvalds3-29/+58
Pull block layer core bits from Jens Axboe: "This is the core pull request for 4.1. Not a lot of stuff in here for this round, mostly little fixes or optimizations. This pull request contains: - An optimization that speeds up queue runs on blk-mq, especially for the case where there's a large difference between nr_cpu_ids and the actual mapped software queues on a hardware queue. From Chong Yuan. - Honor node local allocations for requests on legacy devices. From David Rientjes. - Cleanup of blk_mq_rq_to_pdu() from me. - exit_aio() fixup from me, greatly speeding up exiting multiple IO contexts off exit_group(). For my particular test case, fio exit took ~6 seconds. A typical case of both exposing RCU grace periods to user space, and serializing exit of them. - Make blk_mq_queue_enter() honor the gfp mask passed in, so we only wait if __GFP_WAIT is set. From Keith Busch. - blk-mq exports and two added helpers from Mike Snitzer, which will be used by the dm-mq code. - Cleanups of blk-mq queue init from Wei Fang and Xiaoguang Wang" * 'for-4.1/core' of git://git.kernel.dk/linux-block: blk-mq: reduce unnecessary software queue looping aio: fix serial draining in exit_aio() blk-mq: cleanup blk_mq_rq_to_pdu() blk-mq: put blk_queue_rq_timeout together in blk_mq_init_queue() block: remove redundant check about 'set->nr_hw_queues' in blk_mq_alloc_tag_set() block: allocate request memory local to request queue blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't set blk-mq: export blk_mq_run_hw_queues blk-mq: add blk_mq_init_allocated_queue and export blk_mq_register_disk
2015-04-15blk-mq: reduce unnecessary software queue loopingChong Yuan1-4/+9
In flush_busy_ctxs() and blk_mq_hctx_has_pending(), regardless of how many ctxs assigned to one hctx, they will all loop hctx->ctx_map.map_size times. Here hctx->ctx_map.map_size is a const ALIGN(nr_cpu_ids, 8) / 8. Especially, flush_busy_ctxs() is in hot code path. And it's unnecessary. Change ->map_size to contain the actually mapped software queues, so we only loop for as many iterations as we have to. And remove cpumask setting and nr_ctx count in blk_mq_init_cpu_queues() since they are all re-done in blk_mq_map_swqueue(). blk_mq_map_swqueue(). Signed-off-by: Chong Yuan <chong.yuan@memblaze.com> Reviewed-by: Wenbo Wang <wenbo.wang@memblaze.com> Updated by me for formatting and commenting. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-04-15Merge branch 'for-linus-1' of ↵Linus Torvalds2-10/+8
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs update from Al Viro: "Part one: - struct filename-related cleanups - saner iov_iter_init() replacements (and switching the syscalls to use of those) - ntfs switch to ->write_iter() (Anton) - aio cleanups and splitting iocb into common and async parts (Christoph) - assorted fixes (me, bfields, Andrew Elble) There's a lot more, including the completion of switchover to ->{read,write}_iter(), d_inode/d_backing_inode annotations, f_flags race fixes, etc, but that goes after #for-davem merge. David has pulled it, and once it's in I'll send the next vfs pull request" * 'for-linus-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (35 commits) sg_start_req(): use import_iovec() sg_start_req(): make sure that there's not too many elements in iovec blk_rq_map_user(): use import_single_range() sg_io(): use import_iovec() process_vm_access: switch to {compat_,}import_iovec() switch keyctl_instantiate_key_common() to iov_iter switch {compat_,}do_readv_writev() to {compat_,}import_iovec() aio_setup_vectored_rw(): switch to {compat_,}import_iovec() vmsplice_to_user(): switch to import_iovec() kill aio_setup_single_vector() aio: simplify arguments of aio_setup_..._rw() aio: lift iov_iter_init() into aio_setup_..._rw() lift iov_iter into {compat_,}do_readv_writev() NFS: fix BUG() crash in notify_change() with patch to chown_common() dcache: return -ESTALE not -EBUSY on distributed fs race NTFS: Version 2.1.32 - Update file write from aio_write to write_iter. VFS: Add iov_iter_fault_in_multipages_readable() drop bogus check in file_open_root() switch security_inode_getattr() to struct path * constify tomoyo_realpath_from_path() ...
2015-04-12blk_rq_map_user(): use import_single_range()Al Viro1-3/+3
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-12sg_io(): use import_iovec()Al Viro1-7/+5
... and don't skip access_ok() validation. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-04-11blk-mq: initialize 'struct request' and associated data to zeroLinus Torvalds1-3/+1
Jan Engelhardt reports a strange oops with an invalid ->sense_buffer pointer in scsi_init_cmd_errh() with the blk-mq code. The sense_buffer pointer should have been initialized by the call to scsi_init_request() from blk_mq_init_rq_map(), but there seems to be some non-repeatable memory corruptor. This patch makes sure we initialize the whole struct request allocation (and the associated 'struct scsi_cmnd' for the SCSI case) to zero, by using __GFP_ZERO in the allocation. The old code initialized a couple of individual fields, leaving the rest undefined (although many of them are then initialized in later phases, like blk_mq_rq_ctx_init() etc. It's not entirely clear why this matters, but it's the rigth thing to do regardless, and with 4.0 imminent this is the defensive "let's just make sure everything is initialized properly" patch. Tested-by: Jan Engelhardt <jengelh@inai.de> Acked-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-31block: fix blk_stack_limits() regression due to lcm() changeMike Snitzer1-3/+3
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>
2015-03-30blk-mq: put blk_queue_rq_timeout together in blk_mq_init_queue()Wei Fang1-4/+1
Don't assign ->rq_timeout twice. Signed-off-by: Wei Fang <fangwei1@huawei.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-30block: remove redundant check about 'set->nr_hw_queues' in ↵Xiaoguang Wang1-1/+1
blk_mq_alloc_tag_set() At the beginning of blk_mq_alloc_tag_set(), we have already checked whether 'set->nr_hw_queues' is zero, so here remove this redundant check. Signed-off-by: Xiaoguang Wang <wangxg.fnst@cn.fujitsu.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-25block: allocate request memory local to request queueDavid Rientjes1-3/+16
blk_init_rl() allocates a mempool using mempool_create_node() with node local memory. This only allocates the mempool and element list locally to the requeue queue node. What we really want to do is allocate the request itself local to the queue. To do this, we need our own alloc and free functions that will allocate from request_cachep and pass the request queue node in to prefer node local memory. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-20Fix bug in blk_rq_merge_okWenbo Wang1-1/+1
Use the right array index to reference the last element of rq->biotail->bi_io_vec[] Signed-off-by: Wenbo Wang <wenbo.wang@memblaze.com> Reviewed-by: Chong Yuan <chong.yuan@memblaze.com> Fixes: 66cb45aa41315 ("block: add support for limiting gaps in SG lists") Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-19blkmq: Fix NULL pointer deref when all reserved tags inSam Bradshaw1-2/+4
When allocating from the reserved tags pool, bt_get() is called with a NULL hctx. If all tags are in use, the hw queue is kicked to push out any pending IO, potentially freeing tags, and tag allocation is retried. The problem is that blk_mq_run_hw_queue() doesn't check for a NULL hctx. So we avoid it with a simple NULL hctx test. Tested by hammering mtip32xx with concurrent smartctl/hdparm. Signed-off-by: Sam Bradshaw <sbradshaw@micron.com> Signed-off-by: Selvan Mani <smani@micron.com> Fixes: b32232073e80 ("blk-mq: fix hang in bt_get()") Cc: stable@kernel.org Added appropriate comment. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-13blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't setKeith Busch1-3/+6
Return -EBUSY if we're unable to enter a queue immediately when allocating a blk-mq request without __GFP_WAIT. Signed-off-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-13blk-mq: export blk_mq_run_hw_queuesMike Snitzer1-4/+4
Rename blk_mq_run_queues to blk_mq_run_hw_queues, add async argument, and export it. DM's suspend support must be able to run the queue without starting stopped hw queues. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-13blk-mq: add blk_mq_init_allocated_queue and export blk_mq_register_diskMike Snitzer2-10/+21
Add a variant of blk_mq_init_queue that allows a previously allocated queue to be initialized. blk_mq_init_allocated_queue models blk_init_allocated_queue -- which was also created for DM's use. DM's approach to device creation requires a placeholder request_queue be allocated for use with alloc_dev() but the decision about what type of request_queue will be ultimately created is deferred until all component devices referenced in the DM table are processed to determine the table type (request-based, blk-mq request-based, or bio-based). Also, because of DM's late finalization of the request_queue type the call to blk_mq_register_disk() doesn't happen during alloc_dev(). Must export blk_mq_register_disk() so that DM can backfill the 'mq' dir once the blk-mq queue is fully allocated. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Ming Lei <ming.lei@canonical.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-03-13blk-mq: fix use of incorrect goto label in blk_mq_init_queue error pathMike Snitzer1-3/+3
If percpu_ref_init() fails the allocated q and hctxs must get cleaned up; using 'err_map' doesn't allow that to happen. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Reviewed-by: Ming Lei <ming.lei@canonical.com> Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-21blk-throttle: check stats_cpu before reading it from sysfsThadeu Lima de Souza Cascardo1-0/+3
When reading blkio.throttle.io_serviced in a recently created blkio cgroup, it's possible to race against the creation of a throttle policy, which delays the allocation of stats_cpu. Like other functions in the throttle code, just checking for a NULL stats_cpu prevents the following oops caused by that race. [ 1117.285199] Unable to handle kernel paging request for data at address 0x7fb4d0020 [ 1117.285252] Faulting instruction address: 0xc0000000003efa2c [ 1137.733921] Oops: Kernel access of bad area, sig: 11 [#1] [ 1137.733945] SMP NR_CPUS=2048 NUMA PowerNV [ 1137.734025] Modules linked in: bridge stp llc kvm_hv kvm binfmt_misc autofs4 [ 1137.734102] CPU: 3 PID: 5302 Comm: blkcgroup Not tainted 3.19.0 #5 [ 1137.734132] task: c000000f1d188b00 ti: c000000f1d210000 task.ti: c000000f1d210000 [ 1137.734167] NIP: c0000000003efa2c LR: c0000000003ef9f0 CTR: c0000000003ef980 [ 1137.734202] REGS: c000000f1d213500 TRAP: 0300 Not tainted (3.19.0) [ 1137.734230] MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI> CR: 42008884 XER: 20000000 [ 1137.734325] CFAR: 0000000000008458 DAR: 00000007fb4d0020 DSISR: 40000000 SOFTE: 0 GPR00: c0000000003ed3a0 c000000f1d213780 c000000000c59538 0000000000000000 GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000 GPR08: ffffffffffffffff 00000007fb4d0020 00000007fb4d0000 c000000000780808 GPR12: 0000000022000888 c00000000fdc0d80 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 000001003e120200 c000000f1d5b0cc0 0000000000000200 0000000000000000 GPR24: 0000000000000001 c000000000c269e0 0000000000000020 c000000f1d5b0c80 GPR28: c000000000ca3a08 c000000000ca3dec c000000f1c667e00 c000000f1d213850 [ 1137.734886] NIP [c0000000003efa2c] .tg_prfill_cpu_rwstat+0xac/0x180 [ 1137.734915] LR [c0000000003ef9f0] .tg_prfill_cpu_rwstat+0x70/0x180 [ 1137.734943] Call Trace: [ 1137.734952] [c000000f1d213780] [d000000005560520] 0xd000000005560520 (unreliable) [ 1137.734996] [c000000f1d2138a0] [c0000000003ed3a0] .blkcg_print_blkgs+0xe0/0x1a0 [ 1137.735039] [c000000f1d213960] [c0000000003efb50] .tg_print_cpu_rwstat+0x50/0x70 [ 1137.735082] [c000000f1d2139e0] [c000000000104b48] .cgroup_seqfile_show+0x58/0x150 [ 1137.735125] [c000000f1d213a70] [c0000000002749dc] .kernfs_seq_show+0x3c/0x50 [ 1137.735161] [c000000f1d213ae0] [c000000000218630] .seq_read+0xe0/0x510 [ 1137.735197] [c000000f1d213bd0] [c000000000275b04] .kernfs_fop_read+0x164/0x200 [ 1137.735240] [c000000f1d213c80] [c0000000001eb8e0] .__vfs_read+0x30/0x80 [ 1137.735276] [c000000f1d213cf0] [c0000000001eb9c4] .vfs_read+0x94/0x1b0 [ 1137.735312] [c000000f1d213d90] [c0000000001ebb38] .SyS_read+0x58/0x100 [ 1137.735349] [c000000f1d213e30] [c000000000009218] syscall_exit+0x0/0x98 [ 1137.735383] Instruction dump: [ 1137.735405] 7c6307b4 7f891800 409d00b8 60000000 60420000 3d420004 392a63b0 786a1f24 [ 1137.735471] 7d49502a e93e01c8 7d495214 7d2ad214 <7cead02a> e9090008 e9490010 e9290018 And here is one code that allows to easily reproduce this, although this has first been found by running docker. void run(pid_t pid) { int n; int status; int fd; char *buffer; buffer = memalign(BUFFER_ALIGN, BUFFER_SIZE); n = snprintf(buffer, BUFFER_SIZE, "%d\n", pid); fd = open(CGPATH "/test/tasks", O_WRONLY); write(fd, buffer, n); close(fd); if (fork() > 0) { fd = open("/dev/sda", O_RDONLY | O_DIRECT); read(fd, buffer, 512); close(fd); wait(&status); } else { fd = open(CGPATH "/test/blkio.throttle.io_serviced", O_RDONLY); n = read(fd, buffer, BUFFER_SIZE); close(fd); } free(buffer); exit(0); } void test(void) { int status; mkdir(CGPATH "/test", 0666); if (fork() > 0) wait(&status); else run(getpid()); rmdir(CGPATH "/test"); } int main(int argc, char **argv) { int i; for (i = 0; i < NR_TESTS; i++) test(); return 0; } Reported-by: Ricardo Marin Matinata <rmm@br.ibm.com> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-13Merge branch 'for-3.20/drivers' of git://git.kernel.dk/linux-blockLinus Torvalds1-47/+25
Pull block driver changes from Jens Axboe: "This contains: - The 4k/partition fixes for brd from Boaz/Matthew. - A few xen front/back block fixes from David Vrabel and Roger Pau Monne. - Floppy changes from Takashi, cleaning the device file creation. - Switching libata to use the new blk-mq tagging policy, removing code (and a suboptimal implementation) from libata. This will throw you a merge conflict, since a bug in the original libata tagging code was fixed since this code was branched. Trivial. From Shaohua. - Conversion of loop to blk-mq, from Ming Lei. - Cleanup of the io_schedule() handling in bsg from Peter Zijlstra. He claims it improves on unreadable code, which will cost him a beer. - Maintainer update or NDB, now handled by Markus Pargmann. - NVMe: - Optimization from me that avoids a kmalloc/kfree per IO for smaller (<= 8KB) IO. This cuts about 1% of high IOPS CPU overhead. - Removal of (now) dead RCU code, a relic from before NVMe was converted to blk-mq" * 'for-3.20/drivers' of git://git.kernel.dk/linux-block: xen-blkback: default to X86_32 ABI on x86 xen-blkfront: fix accounting of reqs when migrating xen-blkback,xen-blkfront: add myself as maintainer block: Simplify bsg complete all floppy: Avoid manual call of device_create_file() NVMe: avoid kmalloc/kfree for smaller IO MAINTAINERS: Update NBD maintainer libata: make sata_sil24 use fifo tag allocator libata: move sas ata tag allocation to libata-scsi.c libata: use blk taging NVMe: within nvme_free_queues(), delete RCU sychro/deferred free null_blk: suppress invalid partition info brd: Request from fdisk 4k alignment brd: Fix all partitions BUGs axonram: Fix bug in direct_access loop: add blk-mq.h include block: loop: don't handle REQ_FUA explicitly block: loop: introduce lo_discard() and lo_req_flush() block: loop: say goodby to bio block: loop: improve performance via blk-mq
2015-02-13Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-blockLinus Torvalds13-486/+372
Pull core block IO changes from Jens Axboe: "This contains: - A series from Christoph that cleans up and refactors various parts of the REQ_BLOCK_PC handling. Contributions in that series from Dongsu Park and Kent Overstreet as well. - CFQ: - A bug fix for cfq for realtime IO scheduling from Jeff Moyer. - A stable patch fixing a potential crash in CFQ in OOM situations. From Konstantin Khlebnikov. - blk-mq: - Add support for tag allocation policies, from Shaohua. This is a prep patch enabling libata (and other SCSI parts) to use the blk-mq tagging, instead of rolling their own. - Various little tweaks from Keith and Mike, in preparation for DM blk-mq support. - Minor little fixes or tweaks from me. - A double free error fix from Tony Battersby. - The partition 4k issue fixes from Matthew and Boaz. - Add support for zero+unprovision for blkdev_issue_zeroout() from Martin" * 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits) block: remove unused function blk_bio_map_sg block: handle the null_mapped flag correctly in blk_rq_map_user_iov blk-mq: fix double-free in error path block: prevent request-to-request merging with gaps if not allowed blk-mq: make blk_mq_run_queues() static dm: fix multipath regression due to initializing wrong request cfq-iosched: handle failure of cfq group allocation block: Quiesce zeroout wrapper block: rewrite and split __bio_copy_iov() block: merge __bio_map_user_iov into bio_map_user_iov block: merge __bio_map_kern into bio_map_kern block: pass iov_iter to the BLOCK_PC mapping functions block: add a helper to free bio bounce buffer pages block: use blk_rq_map_user_iov to implement blk_rq_map_user block: simplify bio_map_kern block: mark blk-mq devices as stackable block: keep established cmd_flags when cloning into a blk-mq request block: add blk-mq support to blk_insert_cloned_request() block: require blk_rq_prep_clone() be given an initialized clone request blk-mq: add tag allocation policy ...
2015-02-13Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-blockLinus Torvalds1-1/+1
Pull backing device changes from Jens Axboe: "This contains a cleanup of how the backing device is handled, in preparation for a rework of the life time rules. In this part, the most important change is to split the unrelated nommu mmap flags from it, but also removing a backing_dev_info pointer from the address_space (and inode), and a cleanup of other various minor bits. Christoph did all the work here, I just fixed an oops with pages that have a swap backing. Arnd fixed a missing export, and Oleg killed the lustre backing_dev_info from staging. Last patch was from Al, unexporting parts that are now no longer needed outside" * 'for-3.20/bdi' of git://git.kernel.dk/linux-block: Make super_blocks and sb_lock static mtd: export new mtd_mmap_capabilities fs: make inode_to_bdi() handle NULL inode staging/lustre/llite: get rid of backing_dev_info fs: remove default_backing_dev_info fs: don't reassign dirty inodes to default_backing_dev_info nfs: don't call bdi_unregister ceph: remove call to bdi_unregister fs: remove mapping->backing_dev_info fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info nilfs2: set up s_bdi like the generic mount_bdev code block_dev: get bdev inode bdi directly from the block device block_dev: only write bdev inode on close fs: introduce f_op->mmap_capabilities for nommu mmap support fs: kill BDI_CAP_SWAP_BACKED fs: deduplicate noop_backing_dev_info
2015-02-11block: remove unused function blk_bio_map_sgChristoph Hellwig1-29/+0
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-11block: handle the null_mapped flag correctly in blk_rq_map_user_iovChristoph Hellwig1-0/+3
The tape drivers (and the sg driver in a special case that doesn't matter here) use the null_mapped flag to tell blk_rq_map_user to not copy around any data into or out of the bounce buffers. blk_rq_map_user_iov never got that treatment, which didn't matter until I refactored blk_rq_map_user to be implemented in terms of blk_rq_map_user_iov. Signed-off-by: Christoph Hellwig <hch@lst.de> Fixes: ddad8dd0a162 ("block: use blk_rq_map_user_iov to implement blk_rq_map_user") Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-11blk-mq: fix double-free in error pathTony Battersby1-0/+1
If the allocation of bt->bs fails, then bt->map can be freed twice, once in blk_mq_init_bitmap_tags() -> bt_alloc(), and once in blk_mq_init_bitmap_tags() -> bt_free(). Fix by setting the pointer to NULL after the first free. Cc: <stable@vger.kernel.org> Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-11block: prevent request-to-request merging with gaps if not allowedKeith Busch1-0/+12
If the queue has SG_GAPS set, we must not merge across an sg gap. This is caught for the bio case, but currently not for the more rare case of merging two requests directly. Signed-off-by: Keith Busch <keith.busch@intel.com> Cut the dm bits, those will go through the dm tree, and fixed the test_bit() test. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-10blk-mq: make blk_mq_run_queues() staticJens Axboe1-5/+4
We no longer use it outside of blk-mq.c, so we can make it static and stop exporting it. Additionally, kill the 'async' argument, as there's only one used of it. Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-10Merge branch 'x86-efi-for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull EFI updates from Ingo Molnar: "Main changes: - Move efivarfs from the misc filesystem section to pseudo filesystem - Expose firmware platform size in sysfs - Improve robustness of get_memory_map() by removing assumptions on the size of efi_memory_desc_t. - various cleanups and fixes The biggest risk is the get_memory_map() change, which changes the way that both the arm64 and x86 EFI boot stub build the early memory map. There are no known regressions with it at the moment, BYMMV" * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: efi: Don't look for chosen@0 node on DT platforms firmware: efi: Remove unneeded guid unparse efi/libstub: Call get_memory_map() to obtain map and desc sizes efi: Small leak on error in runtime map code efi: rtc-efi: Mark UIE as unsupported arm64/efi: efistub: Apply __init annotation efi: Expose underlying UEFI firmware platform size to userland efi: Rename efi_guid_unparse to efi_guid_to_str efi: Update the URLs for efibootmgr fs: Make efivarfs a pseudo filesystem, built by default with EFI
2015-02-09cfq-iosched: handle failure of cfq group allocationKonstantin Khlebnikov1-1/+6
Cfq_lookup_create_cfqg() allocates struct blkcg_gq using GFP_ATOMIC. In cfq_find_alloc_queue() possible allocation failure is not handled. As a result kernel oopses on NULL pointer dereference when cfq_link_cfqq_cfqg() calls cfqg_get() for NULL pointer. Bug was introduced in v3.5 in commit cd1604fab4f9 ("blkcg: factor out blkio_group creation"). Prior to that commit cfq group lookup had returned pointer to root group as fallback. This patch handles this error using existing fallback oom_cfqq. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Fixes: cd1604fab4f9 ("blkcg: factor out blkio_group creation") Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: Quiesce zeroout wrapperMartin K. Petersen1-19/+7
blkdev_issue_zeroout() printed a warning if a device failed a discard or write same request despite advertising support for these. That's fine for SCSI since we'll disable these commands if we get an error back from the disk saying that they are not supported. And consequently the warning only gets printed once. There are other types of block devices that support discard, however, and these may return -EOPNOTSUPP for each command but leave discard enabled in the queue limits. This will cause a warning message for every blkdev_issue_zeroout() invocation. Remove the offending warning messages. Reported-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: rewrite and split __bio_copy_iov()Dongsu Park1-34/+56
Rewrite __bio_copy_iov using the copy_page_{from,to}_iter helpers, and split it into two simpler functions. This commit should contain only literal replacements, without functional changes. Cc: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com> [hch: removed the __bio_copy_iov wrapper] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: merge __bio_map_user_iov into bio_map_user_iovChristoph Hellwig2-37/+21
And also remove the unused bdev argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: merge __bio_map_kern into bio_map_kernChristoph Hellwig1-33/+17
This saves a little code, and allow to simplify the error handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: pass iov_iter to the BLOCK_PC mapping functionsKent Overstreet3-111/+90
Make use of a new interface provided by iov_iter, backed by scatter-gather list of iovec, instead of the old interface based on sg_iovec. Also use iov_iter_advance() instead of manual iteration. This commit should contain only literal replacements, without functional changes. Cc: Christoph Hellwig <hch@infradead.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Doug Gilbert <dgilbert@interlog.com> Cc: "James E.J. Bottomley" <JBottomley@parallels.com> Signed-off-by: Kent Overstreet <kmo@daterainc.com> [dpark: add more description in commit message] Signed-off-by: Dongsu Park <dongsu.park@profitbricks.com> [hch: fixed to do a deep clone of the iov_iter, and to properly use the iov_iter direction] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: add a helper to free bio bounce buffer pagesChristoph Hellwig1-32/+33
The code sniplet to walk all bio_vecs and free their pages is opencoded in way to many places, so factor it into a helper. Also convert the slightly more complex cases in bio_kern_endio and __bio_copy_iov where we break the freeing from an existing loop into a separate one. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: use blk_rq_map_user_iov to implement blk_rq_map_userChristoph Hellwig2-176/+14
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-05block: simplify bio_map_kernChristoph Hellwig1-16/+44
Just open code the trivial mapping from a kernel virtual address to a bio instead of going through the complex user address mapping machinery. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-02-04block: Simplify bsg complete allPeter Zijlstra1-47/+25
It took me a few tries to figure out what this code did; lets rewrite it into a more regular form. The thing that makes this one 'special' is the BSG_F_BLOCK flag, if that is not set we're not supposed/allowed to block and should spin wait for completion. The (new) io_wait_event() will never see a false condition in case of the spinning and we will therefore not block. Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Jens Axboe <axboe@fb.com>