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2014-05-05blkcg: use trylock on blkcg_pol_mutex in blkcg_reset_stats()Tejun Heo1-1/+14
During the recent conversion of cgroup to kernfs, cgroup_tree_mutex which nests above both the kernfs s_active protection and cgroup_mutex is added to synchronize cgroup file type operations as cgroup_mutex needed to be grabbed from some file operations and thus can't be put above s_active protection. While this arrangement mostly worked for cgroup, this triggered the following lockdep warning. ====================================================== [ INFO: possible circular locking dependency detected ] 3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429 Tainted: G W ------------------------------------------------------- trinity-c173/9024 is trying to acquire lock: (blkcg_pol_mutex){+.+.+.}, at: blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455) but task is already holding lock: (s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283) which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (s_active#89){++++.+}: lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) __kernfs_remove (arch/x86/include/asm/atomic.h:27 fs/kernfs/dir.c:352 fs/kernfs/dir.c:1024) kernfs_remove_by_name_ns (fs/kernfs/dir.c:1219) cgroup_addrm_files (include/linux/kernfs.h:427 kernel/cgroup.c:1074 kernel/cgroup.c:2899) cgroup_clear_dir (kernel/cgroup.c:1092 (discriminator 2)) rebind_subsystems (kernel/cgroup.c:1144) cgroup_setup_root (kernel/cgroup.c:1568) cgroup_mount (kernel/cgroup.c:1716) mount_fs (fs/super.c:1094) vfs_kern_mount (fs/namespace.c:899) do_mount (fs/namespace.c:2238 fs/namespace.c:2561) SyS_mount (fs/namespace.c:2758 fs/namespace.c:2729) tracesys (arch/x86/kernel/entry_64.S:746) -> #1 (cgroup_tree_mutex){+.+.+.}: lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587) cgroup_add_cftypes (include/linux/list.h:76 kernel/cgroup.c:3040) blkcg_policy_register (block/blk-cgroup.c:1106) throtl_init (block/blk-throttle.c:1694) do_one_initcall (init/main.c:789) kernel_init_freeable (init/main.c:854 init/main.c:863 init/main.c:882 init/main.c:1003) kernel_init (init/main.c:935) ret_from_fork (arch/x86/kernel/entry_64.S:552) -> #0 (blkcg_pol_mutex){+.+.+.}: __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182) lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587) blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455) cgroup_file_write (kernel/cgroup.c:2714) kernfs_fop_write (fs/kernfs/file.c:295) vfs_write (fs/read_write.c:532) SyS_write (fs/read_write.c:584 fs/read_write.c:576) tracesys (arch/x86/kernel/entry_64.S:746) other info that might help us debug this: Chain exists of: blkcg_pol_mutex --> cgroup_tree_mutex --> s_active#89 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(s_active#89); lock(cgroup_tree_mutex); lock(s_active#89); lock(blkcg_pol_mutex); *** DEADLOCK *** 4 locks held by trinity-c173/9024: #0: (&f->f_pos_lock){+.+.+.}, at: __fdget_pos (fs/file.c:714) #1: (sb_writers#18){.+.+.+}, at: vfs_write (include/linux/fs.h:2255 fs/read_write.c:530) #2: (&of->mutex){+.+.+.}, at: kernfs_fop_write (fs/kernfs/file.c:283) #3: (s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283) stack backtrace: CPU: 3 PID: 9024 Comm: trinity-c173 Tainted: G W 3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429 ffffffff919687b0 ffff8805f6373bb8 ffffffff8e52cdbb 0000000000000002 ffffffff919d8400 ffff8805f6373c08 ffffffff8e51fb88 0000000000000004 ffff8805f6373c98 ffff8805f6373c08 ffff88061be70d98 ffff88061be70dd0 Call Trace: dump_stack (lib/dump_stack.c:52) print_circular_bug (kernel/locking/lockdep.c:1216) __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182) lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587) blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455) cgroup_file_write (kernel/cgroup.c:2714) kernfs_fop_write (fs/kernfs/file.c:295) vfs_write (fs/read_write.c:532) SyS_write (fs/read_write.c:584 fs/read_write.c:576) This is a highly unlikely but valid circular dependency between "echo 1 > blkcg.reset_stats" and cfq module [un]loading. cgroup is going through further locking update which will remove this complication but for now let's use trylock on blkcg_pol_mutex and retry the file operation if the trylock fails. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Sasha Levin <sasha.levin@oracle.com> References: http://lkml.kernel.org/g/5363C04B.4010400@oracle.com
2014-04-12Merge branch 'for-linus' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull vfs updates from Al Viro: "The first vfs pile, with deep apologies for being very late in this window. Assorted cleanups and fixes, plus a large preparatory part of iov_iter work. There's a lot more of that, but it'll probably go into the next merge window - it *does* shape up nicely, removes a lot of boilerplate, gets rid of locking inconsistencie between aio_write and splice_write and I hope to get Kent's direct-io rewrite merged into the same queue, but some of the stuff after this point is having (mostly trivial) conflicts with the things already merged into mainline and with some I want more testing. This one passes LTP and xfstests without regressions, in addition to usual beating. BTW, readahead02 in ltp syscalls testsuite has started giving failures since "mm/readahead.c: fix readahead failure for memoryless NUMA nodes and limit readahead pages" - might be a false positive, might be a real regression..." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits) missing bits of "splice: fix racy pipe->buffers uses" cifs: fix the race in cifs_writev() ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure kill generic_file_buffered_write() ocfs2_file_aio_write(): switch to generic_perform_write() ceph_aio_write(): switch to generic_perform_write() xfs_file_buffered_aio_write(): switch to generic_perform_write() export generic_perform_write(), start getting rid of generic_file_buffer_write() generic_file_direct_write(): get rid of ppos argument btrfs_file_aio_write(): get rid of ppos kill the 5th argument of generic_file_buffered_write() kill the 4th argument of __generic_file_aio_write() lustre: don't open-code kernel_recvmsg() ocfs2: don't open-code kernel_recvmsg() drbd: don't open-code kernel_recvmsg() constify blk_rq_map_user_iov() and friends lustre: switch to kernel_sendmsg() ocfs2: don't open-code kernel_sendmsg() take iov_iter stuff to mm/iov_iter.c process_vm_access: tidy up a bit ...
2014-04-09block: fix regression with block enabled taggingJens Axboe4-13/+10
Martin reported that his test system would not boot with current git, it oopsed with this: BUG: unable to handle kernel paging request at ffff88046c6c9e80 IP: [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150 PGD 1ddf067 PUD 1de2067 PMD 47fc7d067 PTE 800000046c6c9060 Oops: 0002 [#1] SMP DEBUG_PAGEALLOC Modules linked in: sd_mod lpfc(+) scsi_transport_fc scsi_tgt oracleasm rpcsec_gss_krb5 ipv6 igb dca i2c_algo_bit i2c_core hwmon CPU: 3 PID: 87 Comm: kworker/u17:1 Not tainted 3.14.0+ #246 Hardware name: Supermicro X9DRX+-F/X9DRX+-F, BIOS 3.00 07/09/2013 Workqueue: events_unbound async_run_entry_fn task: ffff8802743c2150 ti: ffff880273d02000 task.ti: ffff880273d02000 RIP: 0010:[<ffffffff812971e0>] [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150 RSP: 0018:ffff880273d03a58 EFLAGS: 00010092 RAX: ffff88046c6c9e78 RBX: ffff880077208e78 RCX: 00000000fffc8da6 RDX: 00000000fffc186d RSI: 0000000000000009 RDI: 00000000fffc8d9d RBP: ffff880273d03a88 R08: 0000000000000001 R09: ffff8800021c2410 R10: 0000000000000005 R11: 0000000000015b30 R12: ffff88046c5bb8a0 R13: ffff88046c5c0890 R14: 000000000000001e R15: 000000000000001e FS: 0000000000000000(0000) GS:ffff880277b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffff88046c6c9e80 CR3: 00000000018f6000 CR4: 00000000000407e0 Stack: ffff880273d03a98 ffff880474b18800 0000000000000000 ffff880474157000 ffff88046c5c0890 ffff880077208e78 ffff880273d03ae8 ffffffff813b9e62 ffff880200000010 ffff880474b18968 ffff880474b18848 ffff88046c5c0cd8 Call Trace: [<ffffffff813b9e62>] scsi_request_fn+0xf2/0x510 [<ffffffff81293167>] __blk_run_queue+0x37/0x50 [<ffffffff8129ac43>] blk_execute_rq_nowait+0xb3/0x130 [<ffffffff8129ad24>] blk_execute_rq+0x64/0xf0 [<ffffffff8108d2b0>] ? bit_waitqueue+0xd0/0xd0 [<ffffffff813bba35>] scsi_execute+0xe5/0x180 [<ffffffff813bbe4a>] scsi_execute_req_flags+0x9a/0x110 [<ffffffffa01b1304>] sd_spinup_disk+0x94/0x460 [sd_mod] [<ffffffff81160000>] ? __unmap_hugepage_range+0x200/0x2f0 [<ffffffffa01b2b9a>] sd_revalidate_disk+0xaa/0x3f0 [sd_mod] [<ffffffffa01b2fb8>] sd_probe_async+0xd8/0x200 [sd_mod] [<ffffffff8107703f>] async_run_entry_fn+0x3f/0x140 [<ffffffff8106a1c5>] process_one_work+0x175/0x410 [<ffffffff8106b373>] worker_thread+0x123/0x400 [<ffffffff8106b250>] ? manage_workers+0x160/0x160 [<ffffffff8107104e>] kthread+0xce/0xf0 [<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70 [<ffffffff815f0bac>] ret_from_fork+0x7c/0xb0 [<ffffffff81070f80>] ? kthread_freezable_should_stop+0x70/0x70 Code: 48 0f ab 11 72 db 48 81 4b 40 00 00 10 00 89 83 08 01 00 00 48 89 df 49 8b 04 24 48 89 1c d0 e8 f7 a8 ff ff 49 8b 85 28 05 00 00 <48> 89 58 08 48 89 03 49 8d 85 28 05 00 00 48 89 43 08 49 89 9d RIP [<ffffffff812971e0>] blk_queue_start_tag+0x90/0x150 RSP <ffff880273d03a58> CR2: ffff88046c6c9e80 Martin bisected and found this to be the problem patch; commit 6d113398dcf4dfcd9787a4ead738b186f7b7ff0f Author: Jan Kara <jack@suse.cz> Date: Mon Feb 24 16:39:54 2014 +0100 block: Stop abusing rq->csd.list in blk-softirq and the problem was immediately apparent. The patch states that it is safe to reuse queuelist at completion time, since it is no longer used. However, that is not true if a device is using block enabled tagging. If that is the case, then the queuelist is reused to keep track of busy tags. If a device also ended up using softirq completions, we'd reuse ->queuelist for the IPI handling while block tagging was still using it. Boom. Fix this by adding a new ipi_list list head, and share the memory used with the request hash table. The hash table is never used after the request is moved to the dispatch list, which happens long before any potential completion of the request. Add a new request bit for this, so we don't have cases that check rq->hash while it could potentially have been reused for the IPI completion. Reported-by: Martin K. Petersen <martin.petersen@oracle.com> Tested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-07blk-mq: fix potential stall during CPU unplug with IO pendingJens Axboe1-2/+6
When a CPU is unplugged, we move the blk_mq_ctx request entries to the current queue. The current code forgets to remap the blk_mq_hw_ctx before marking the software context pending, which breaks if old-cpu and new-cpu don't map to the same hardware queue. Additionally, if we mark entries as pending in the new hardware queue, then make sure we schedule it for running. Otherwise request could be sitting there until someone else queues IO for that hardware queue. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-03Merge branch 'for-3.15' of ↵Linus Torvalds4-23/+17
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "A lot updates for cgroup: - The biggest one is cgroup's conversion to kernfs. cgroup took after the long abandoned vfs-entangled sysfs implementation and made it even more convoluted over time. cgroup's internal objects were fused with vfs objects which also brought in vfs locking and object lifetime rules. Naturally, there are places where vfs rules don't fit and nasty hacks, such as credential switching or lock dance interleaving inode mutex and cgroup_mutex with object serial number comparison thrown in to decide whether the operation is actually necessary, needed to be employed. After conversion to kernfs, internal object lifetime and locking rules are mostly isolated from vfs interactions allowing shedding of several nasty hacks and overall simplification. This will also allow implmentation of operations which may affect multiple cgroups which weren't possible before as it would have required nesting i_mutexes. - Various simplifications including dropping of module support, easier cgroup name/path handling, simplified cgroup file type handling and task_cg_lists optimization. - Prepatory changes for the planned unified hierarchy, which is still a patchset away from being actually operational. The dummy hierarchy is updated to serve as the default unified hierarchy. Controllers which aren't claimed by other hierarchies are associated with it, which BTW was what the dummy hierarchy was for anyway. - Various fixes from Li and others. This pull request includes some patches to add missing slab.h to various subsystems. This was triggered xattr.h include removal from cgroup.h. cgroup.h indirectly got included a lot of files which brought in xattr.h which brought in slab.h. There are several merge commits - one to pull in kernfs updates necessary for converting cgroup (already in upstream through driver-core), others for interfering changes in the fixes branch" * 'for-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (74 commits) cgroup: remove useless argument from cgroup_exit() cgroup: fix spurious lockdep warning in cgroup_exit() cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c cgroup: break kernfs active_ref protection in cgroup directory operations cgroup: fix cgroup_taskset walking order cgroup: implement CFTYPE_ONLY_ON_DFL cgroup: make cgrp_dfl_root mountable cgroup: drop const from @buffer of cftype->write_string() cgroup: rename cgroup_dummy_root and related names cgroup: move ->subsys_mask from cgroupfs_root to cgroup cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding cgroup: remove NULL checks from [pr_cont_]cgroup_{name|path}() cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root cgroup: reorganize cgroup bootstrapping cgroup: relocate setting of CGRP_DEAD cpuset: use rcu_read_lock() to protect task_cs() cgroup_freezer: document freezer_fork() subtleties cgroup: update cgroup_transfer_tasks() to either succeed or fail cgroup: drop task_lock() protection around task->cgroups cgroup: update how a newly forked task gets associated with css_set ...
2014-04-02Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-4/+4
Pull networking updates from David Miller: "Here is my initial pull request for the networking subsystem during this merge window: 1) Support for ESN in AH (RFC 4302) from Fan Du. 2) Add full kernel doc for ethtool command structures, from Ben Hutchings. 3) Add BCM7xxx PHY driver, from Florian Fainelli. 4) Export computed TCP rate information in netlink socket dumps, from Eric Dumazet. 5) Allow IPSEC SA to be dumped partially using a filter, from Nicolas Dichtel. 6) Convert many drivers to pci_enable_msix_range(), from Alexander Gordeev. 7) Record SKB timestamps more efficiently, from Eric Dumazet. 8) Switch to microsecond resolution for TCP round trip times, also from Eric Dumazet. 9) Clean up and fix 6lowpan fragmentation handling by making use of the existing inet_frag api for it's implementation. 10) Add TX grant mapping to xen-netback driver, from Zoltan Kiss. 11) Auto size SKB lengths when composing netlink messages based upon past message sizes used, from Eric Dumazet. 12) qdisc dumps can take a long time, add a cond_resched(), From Eric Dumazet. 13) Sanitize netpoll core and drivers wrt. SKB handling semantics. Get rid of never-used-in-tree netpoll RX handling. From Eric W Biederman. 14) Support inter-address-family and namespace changing in VTI tunnel driver(s). From Steffen Klassert. 15) Add Altera TSE driver, from Vince Bridgers. 16) Optimizing csum_replace2() so that it doesn't adjust the checksum by checksumming the entire header, from Eric Dumazet. 17) Expand BPF internal implementation for faster interpreting, more direct translations into JIT'd code, and much cleaner uses of BPF filtering in non-socket ocntexts. From Daniel Borkmann and Alexei Starovoitov" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1976 commits) netpoll: Use skb_irq_freeable to make zap_completion_queue safe. net: Add a test to see if a skb is freeable in irq context qlcnic: Fix build failure due to undefined reference to `vxlan_get_rx_port' net: ptp: move PTP classifier in its own file net: sxgbe: make "core_ops" static net: sxgbe: fix logical vs bitwise operation net: sxgbe: sxgbe_mdio_register() frees the bus Call efx_set_channels() before efx->type->dimension_resources() xen-netback: disable rogue vif in kthread context net/mlx4: Set proper build dependancy with vxlan be2net: fix build dependency on VxLAN mac802154: make csma/cca parameters per-wpan mac802154: allow only one WPAN to be up at any given time net: filter: minor: fix kdoc in __sk_run_filter netlink: don't compare the nul-termination in nla_strcmp can: c_can: Avoid led toggling for every packet. can: c_can: Simplify TX interrupt cleanup can: c_can: Store dlc private can: c_can: Reduce register access can: c_can: Make the code readable ...
2014-04-02Merge branch 'for-linus' of ↵Linus Torvalds2-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina: "Usual rocket science -- mostly documentation and comment updates" * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: sparse: fix comment doc: fix double words isdn: capi: fix "CAPI_VERSION" comment doc: DocBook: Fix typos in xml and template file Bluetooth: add module name for btwilink driver core: unexport static function create_syslog_header mmc: core: typo fix in printk specifier ARM: spear: clean up editing mistake net-sysfs: fix comment typo 'CONFIG_SYFS' doc: Insert MODULE_ in module-signing macros Documentation: update URL to hfsplus Technote 1150 gpio: update path to documentation ixgbe: Fix format string in ixgbe_fcoe. Kconfig: Remove useless "default N" lines user_namespace.c: Remove duplicated word in comment CREDITS: fix formatting treewide: Fix typo in Documentation/DocBook mm: Fix warning on make htmldocs caused by slab.c ata: ata-samsung_cf: cleanup in header file idr: remove unused prototype of idr_free()
2014-04-01constify blk_rq_map_user_iov() and friendsAl Viro1-1/+1
sg_iovec array passed to it can be const Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2014-04-01Merge branch 'for-3.15/core' of git://git.kernel.dk/linux-blockLinus Torvalds14-48/+125
Pull core block layer updates from Jens Axboe: "This is the pull request for the core block IO bits for the 3.15 kernel. It's a smaller round this time, it contains: - Various little blk-mq fixes and additions from Christoph and myself. - Cleanup of the IPI usage from the block layer, and associated helper code. From Frederic Weisbecker and Jan Kara. - Duplicate code cleanup in bio-integrity from Gu Zheng. This will give you a merge conflict, but that should be easy to resolve. - blk-mq notify spinlock fix for RT from Mike Galbraith. - A blktrace partial accounting bug fix from Roman Pen. - Missing REQ_SYNC detection fix for blk-mq from Shaohua Li" * 'for-3.15/core' of git://git.kernel.dk/linux-block: (25 commits) blk-mq: add REQ_SYNC early rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlock blk-mq: support partial I/O completions blk-mq: merge blk_mq_insert_request and blk_mq_run_request blk-mq: remove blk_mq_alloc_rq blk-mq: don't dump CPU -> hw queue map on driver load blk-mq: fix wrong usage of hctx->state vs hctx->flags blk-mq: allow blk_mq_init_commands() to return failure block: remove old blk_iopoll_enabled variable blktrace: fix accounting of partially completed requests smp: Rename __smp_call_function_single() to smp_call_function_single_async() smp: Remove wait argument from __smp_call_function_single() watchdog: Simplify a little the IPI call smp: Move __smp_call_function_single() below its safe version smp: Consolidate the various smp_call_function_single() declensions smp: Teach __smp_call_function_single() to check for offline cpus smp: Remove unused list_head from csd smp: Iterate functions through llist_for_each_entry_safe() block: Stop abusing rq->csd.list in blk-softirq block: Remove useless IPI struct initialization ...
2014-03-25Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netDavid S. Miller2-17/+19
Conflicts: Documentation/devicetree/bindings/net/micrel-ks8851.txt net/core/netpoll.c The net/core/netpoll.c conflict is a bug fix in 'net' happening to code which is completely removed in 'net-next'. In micrel-ks8851.txt we simply have overlapping changes. Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-21blk-mq: add REQ_SYNC earlyShaohua Li1-0/+2
Add REQ_SYNC early, so rq_dispatched[] in blk_mq_rq_ctx_init is set correctly. Signed-off-by: Shaohua Li<shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlockMike Galbraith1-7/+7
[ 365.164040] BUG: sleeping function called from invalid context at kernel/rtmutex.c:674 [ 365.164041] in_atomic(): 1, irqs_disabled(): 1, pid: 26, name: migration/1 [ 365.164043] no locks held by migration/1/26. [ 365.164044] irq event stamp: 6648 [ 365.164056] hardirqs last enabled at (6647): [<ffffffff8153d377>] restore_args+0x0/0x30 [ 365.164062] hardirqs last disabled at (6648): [<ffffffff810ed98d>] multi_cpu_stop+0x9d/0x120 [ 365.164070] softirqs last enabled at (0): [<ffffffff810543bc>] copy_process.part.28+0x6fc/0x1920 [ 365.164072] softirqs last disabled at (0): [< (null)>] (null) [ 365.164076] CPU: 1 PID: 26 Comm: migration/1 Tainted: GF N 3.12.12-rt19-0.gcb6c4a2-rt #3 [ 365.164078] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011 [ 365.164091] 0000000000000001 ffff880a42ea7c30 ffffffff815367e6 ffffffff81a086c0 [ 365.164099] ffff880a42ea7c40 ffffffff8108919c ffff880a42ea7c60 ffffffff8153c24f [ 365.164107] ffff880a42ea91f0 00000000ffffffe1 ffff880a42ea7c88 ffffffff81297ec0 [ 365.164108] Call Trace: [ 365.164119] [<ffffffff810060b1>] try_stack_unwind+0x191/0x1a0 [ 365.164127] [<ffffffff81004872>] dump_trace+0x92/0x360 [ 365.164133] [<ffffffff81006108>] show_trace_log_lvl+0x48/0x60 [ 365.164138] [<ffffffff81004c18>] show_stack_log_lvl+0xd8/0x1d0 [ 365.164143] [<ffffffff81006160>] show_stack+0x20/0x50 [ 365.164153] [<ffffffff815367e6>] dump_stack+0x54/0x9a [ 365.164163] [<ffffffff8108919c>] __might_sleep+0xfc/0x140 [ 365.164173] [<ffffffff8153c24f>] rt_spin_lock+0x1f/0x70 [ 365.164182] [<ffffffff81297ec0>] blk_mq_main_cpu_notify+0x20/0x70 [ 365.164191] [<ffffffff81540a1c>] notifier_call_chain+0x4c/0x70 [ 365.164201] [<ffffffff81083499>] __raw_notifier_call_chain+0x9/0x10 [ 365.164207] [<ffffffff810567be>] cpu_notify+0x1e/0x40 [ 365.164217] [<ffffffff81525da2>] take_cpu_down+0x22/0x40 [ 365.164223] [<ffffffff810ed9c6>] multi_cpu_stop+0xd6/0x120 [ 365.164229] [<ffffffff810edd97>] cpu_stopper_thread+0xd7/0x1e0 [ 365.164235] [<ffffffff810863a3>] smpboot_thread_fn+0x203/0x380 [ 365.164241] [<ffffffff8107cbf8>] kthread+0xc8/0xd0 [ 365.164250] [<ffffffff8154440c>] ret_from_fork+0x7c/0xb0 [ 365.164429] smpboot: CPU 1 is now offline Signed-off-by: Mike Galbraith <bitbucket@online.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21blk-mq: support partial I/O completionsChristoph Hellwig1-32/+5
Add a new blk_mq_end_io_partial function to partially complete requests as needed by the SCSI layer. We do this by reusing blk_update_request to advance the bio instead of having a simplified version of it in the blk-mq code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21blk-mq: merge blk_mq_insert_request and blk_mq_run_requestChristoph Hellwig4-47/+13
It's almost identical to blk_mq_insert_request, so fold the two into one slightly more generic function by making the flush special case a bit smarted. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-21blk-mq: remove blk_mq_alloc_rqChristoph Hellwig1-8/+2
There's only one caller, which is a straight wrapper and fits the naming scheme of the related functions a lot better. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-20block: free q->flush_rq in blk_init_allocated_queue error pathsDave Jones1-2/+6
Commit 7982e90c3a57 ("block: fix q->flush_rq NULL pointer crash on dm-mpath flush") moved an allocation to blk_init_allocated_queue(), but neglected to free that allocation on the error paths that follow. Signed-off-by: Dave Jones <davej@fedoraproject.org> Acked-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-03-20blk-mq: don't dump CPU -> hw queue map on driver loadJens Axboe4-10/+43
Now that we are out of initial debug/bringup mode, remove the verbose dump of the mapping table. Provide the mapping table in sysfs, under the hardware queue directory, in the cpu_list file. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-19blk-mq: fix wrong usage of hctx->state vs hctx->flagsJens Axboe1-3/+3
BLK_MQ_F_* flags are for hctx->flags, and are non-atomic and set at registration time. BLK_MQ_S_* flags are dynamic and atomic, and are accessed through hctx->state. Some of the BLK_MQ_S_STOPPED uses were wrong. Additionally, the header file should not use a bit shift for the _S_ flags, as they are done through the set/test_bit functions. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-19cgroup: drop const from @buffer of cftype->write_string()Tejun Heo2-4/+4
cftype->write_string() just passes on the writeable buffer from kernfs and there's no reason to add const restriction on the buffer. The only thing const achieves is unnecessarily complicating parsing of the buffer. Drop const from @buffer. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2014-03-14net: Replace u64_stats_fetch_begin_bh to u64_stats_fetch_begin_irqEric W. Biederman1-4/+4
Replace the bh safe variant with the hard irq safe variant. We need a hard irq safe variant to deal with netpoll transmitting packets from hard irq context, and we need it in most if not all of the places using the bh safe variant. Except on 32bit uni-processor the code is exactly the same so don't bother with a bh variant, just have a hard irq safe variant that everyone can use. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-14blk-mq: allow blk_mq_init_commands() to return failureJens Axboe1-7/+45
If drivers do dynamic allocation in the hardware command init path, then we need to be able to handle and return failures. And if they do allocations or mappings in the init command path, then we need a cleanup function to free up that space at exit time. So add blk_mq_free_commands() as the cleanup function. This is required for the mtip32xx driver conversion to blk-mq. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-13block: remove old blk_iopoll_enabled variableJens Axboe1-3/+0
This was a debugging measure to toggle enabled/disabled when testing. But for real production setups, it's not safe to toggle this setting without either reloading drivers of quiescing IO first. Neither of which the toggle enforces. Additionally, it makes drivers deal with the conditional state. Remove it completely. It's up to the driver whether iopoll is enabled or not. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-08block: change flush sequence list addition back to front addMike Snitzer1-4/+7
Commit 18741986 inadvertently changed the rq flush insertion from a head to a tail insertion. Fix that back up. Signed-off-by: Mike Snitzer <msnitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-08block: fix q->flush_rq NULL pointer crash on dm-mpath flushMike Snitzer1-11/+6
Commit 1874198 ("blk-mq: rework flush sequencing logic") switched ->flush_rq from being an embedded member of the request_queue structure to being dynamically allocated in blk_init_queue_node(). Request-based DM multipath doesn't use blk_init_queue_node(), instead it uses blk_alloc_queue_node() + blk_init_allocated_queue(). Because commit 1874198 placed the dynamic allocation of ->flush_rq in blk_init_queue_node() any flush issued to a dm-mpath device would crash with a NULL pointer, e.g.: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff8125037e>] blk_rq_init+0x1e/0xb0 PGD bb3c7067 PUD bb01d067 PMD 0 Oops: 0002 [#1] SMP ... CPU: 5 PID: 5028 Comm: dt Tainted: G W O 3.14.0-rc3.snitm+ #10 ... task: ffff88032fb270e0 ti: ffff880079564000 task.ti: ffff880079564000 RIP: 0010:[<ffffffff8125037e>] [<ffffffff8125037e>] blk_rq_init+0x1e/0xb0 RSP: 0018:ffff880079565c98 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000030 RDX: ffff880260c74048 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff880079565ca8 R08: ffff880260aa1e98 R09: 0000000000000001 R10: ffff88032fa78500 R11: 0000000000000246 R12: 0000000000000000 R13: ffff880260aa1de8 R14: 0000000000000650 R15: 0000000000000000 FS: 00007f8d36a2a700(0000) GS:ffff88033fca0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000079b36000 CR4: 00000000000007e0 Stack: 0000000000000000 ffff880260c74048 ffff880079565cd8 ffffffff81257a47 ffff880260aa1de8 ffff880260c74048 0000000000000001 0000000000000000 ffff880079565d08 ffffffff81257c2d 0000000000000000 ffff880260aa1de8 Call Trace: [<ffffffff81257a47>] blk_flush_complete_seq+0x2d7/0x2e0 [<ffffffff81257c2d>] blk_insert_flush+0x1dd/0x210 [<ffffffff8124ec59>] __elv_add_request+0x1f9/0x320 [<ffffffff81250681>] ? blk_account_io_start+0x111/0x190 [<ffffffff81253a4b>] blk_queue_bio+0x25b/0x330 [<ffffffffa0020bf5>] dm_request+0x35/0x40 [dm_mod] [<ffffffff812530c0>] generic_make_request+0xc0/0x100 [<ffffffff81253173>] submit_bio+0x73/0x140 [<ffffffff811becdd>] submit_bio_wait+0x5d/0x80 [<ffffffff81257528>] blkdev_issue_flush+0x78/0xa0 [<ffffffff811c1f6f>] blkdev_fsync+0x3f/0x60 [<ffffffff811b7fde>] vfs_fsync_range+0x1e/0x20 [<ffffffff811b7ffc>] vfs_fsync+0x1c/0x20 [<ffffffff811b81f1>] do_fsync+0x41/0x80 [<ffffffff8118874e>] ? SyS_lseek+0x7e/0x80 [<ffffffff811b8260>] SyS_fsync+0x10/0x20 [<ffffffff8154c2d2>] system_call_fastpath+0x16/0x1b Fix this by moving the ->flush_rq allocation from blk_init_queue_node() to blk_init_allocated_queue(). blk_init_queue_node() also calls blk_init_allocated_queue() so this change is functionality equivalent for all blk_init_queue_node() callers. Reported-by: Hannes Reinecke <hare@suse.de> Reported-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-07blk-mq: add REQ_SYNC earlyShaohua Li1-0/+2
Add REQ_SYNC early, so rq_dispatched[] in blk_mq_rq_ctx_init is set correctly. Signed-off-by: Shaohua Li<shli@fusionio.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-05blktrace: fix accounting of partially completed requestsRoman Pen2-2/+2
trace_block_rq_complete does not take into account that request can be partially completed, so we can get the following incorrect output of blkparser: C R 232 + 240 [0] C R 240 + 232 [0] C R 248 + 224 [0] C R 256 + 216 [0] but should be: C R 232 + 8 [0] C R 240 + 8 [0] C R 248 + 8 [0] C R 256 + 8 [0] Also, the whole output summary statistics of completed requests and final throughput will be incorrect. This patch takes into account real completion size of the request and fixes wrong completion accounting. Signed-off-by: Roman Pen <r.peniaev@gmail.com> CC: Steven Rostedt <rostedt@goodmis.org> CC: Frederic Weisbecker <fweisbec@gmail.com> CC: Ingo Molnar <mingo@redhat.com> CC: linux-kernel@vger.kernel.org Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-03rt,blk,mq: Make blk_mq_cpu_notify_lock a raw spinlockMike Galbraith1-7/+7
[ 365.164040] BUG: sleeping function called from invalid context at kernel/rtmutex.c:674 [ 365.164041] in_atomic(): 1, irqs_disabled(): 1, pid: 26, name: migration/1 [ 365.164043] no locks held by migration/1/26. [ 365.164044] irq event stamp: 6648 [ 365.164056] hardirqs last enabled at (6647): [<ffffffff8153d377>] restore_args+0x0/0x30 [ 365.164062] hardirqs last disabled at (6648): [<ffffffff810ed98d>] multi_cpu_stop+0x9d/0x120 [ 365.164070] softirqs last enabled at (0): [<ffffffff810543bc>] copy_process.part.28+0x6fc/0x1920 [ 365.164072] softirqs last disabled at (0): [< (null)>] (null) [ 365.164076] CPU: 1 PID: 26 Comm: migration/1 Tainted: GF N 3.12.12-rt19-0.gcb6c4a2-rt #3 [ 365.164078] Hardware name: QCI QSSC-S4R/QSSC-S4R, BIOS QSSC-S4R.QCI.01.00.S013.032920111005 03/29/2011 [ 365.164091] 0000000000000001 ffff880a42ea7c30 ffffffff815367e6 ffffffff81a086c0 [ 365.164099] ffff880a42ea7c40 ffffffff8108919c ffff880a42ea7c60 ffffffff8153c24f [ 365.164107] ffff880a42ea91f0 00000000ffffffe1 ffff880a42ea7c88 ffffffff81297ec0 [ 365.164108] Call Trace: [ 365.164119] [<ffffffff810060b1>] try_stack_unwind+0x191/0x1a0 [ 365.164127] [<ffffffff81004872>] dump_trace+0x92/0x360 [ 365.164133] [<ffffffff81006108>] show_trace_log_lvl+0x48/0x60 [ 365.164138] [<ffffffff81004c18>] show_stack_log_lvl+0xd8/0x1d0 [ 365.164143] [<ffffffff81006160>] show_stack+0x20/0x50 [ 365.164153] [<ffffffff815367e6>] dump_stack+0x54/0x9a [ 365.164163] [<ffffffff8108919c>] __might_sleep+0xfc/0x140 [ 365.164173] [<ffffffff8153c24f>] rt_spin_lock+0x1f/0x70 [ 365.164182] [<ffffffff81297ec0>] blk_mq_main_cpu_notify+0x20/0x70 [ 365.164191] [<ffffffff81540a1c>] notifier_call_chain+0x4c/0x70 [ 365.164201] [<ffffffff81083499>] __raw_notifier_call_chain+0x9/0x10 [ 365.164207] [<ffffffff810567be>] cpu_notify+0x1e/0x40 [ 365.164217] [<ffffffff81525da2>] take_cpu_down+0x22/0x40 [ 365.164223] [<ffffffff810ed9c6>] multi_cpu_stop+0xd6/0x120 [ 365.164229] [<ffffffff810edd97>] cpu_stopper_thread+0xd7/0x1e0 [ 365.164235] [<ffffffff810863a3>] smpboot_thread_fn+0x203/0x380 [ 365.164241] [<ffffffff8107cbf8>] kthread+0xc8/0xd0 [ 365.164250] [<ffffffff8154440c>] ret_from_fork+0x7c/0xb0 [ 365.164429] smpboot: CPU 1 is now offline Signed-off-by: Mike Galbraith <bitbucket@online.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24smp: Rename __smp_call_function_single() to smp_call_function_single_async()Frederic Weisbecker2-2/+2
The name __smp_call_function_single() doesn't tell much about the properties of this function, especially when compared to smp_call_function_single(). The comments above the implementation are also misleading. The main point of this function is actually not to be able to embed the csd in an object. This is actually a requirement that result from the purpose of this function which is to raise an IPI asynchronously. As such it can be called with interrupts disabled. And this feature comes at the cost of the caller who then needs to serialize the IPIs on this csd. Lets rename the function and enhance the comments so that they reflect these properties. Suggested-by: Christoph Hellwig <hch@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24smp: Remove wait argument from __smp_call_function_single()Frederic Weisbecker2-2/+2
The main point of calling __smp_call_function_single() is to send an IPI in a pure asynchronous way. By embedding a csd in an object, a caller can send the IPI without waiting for a previous one to complete as is required by smp_call_function_single() for example. As such, sending this kind of IPI can be safe even when irqs are disabled. This flexibility comes at the expense of the caller who then needs to synchronize the csd lifecycle by himself and make sure that IPIs on a single csd are serialized. This is how __smp_call_function_single() works when wait = 0 and this usecase is relevant. Now there don't seem to be any usecase with wait = 1 that can't be covered by smp_call_function_single() instead, which is safer. Lets look at the two possible scenario: 1) The user calls __smp_call_function_single(wait = 1) on a csd embedded in an object. It looks like a nice and convenient pattern at the first sight because we can then retrieve the object from the IPI handler easily. But actually it is a waste of memory space in the object since the csd can be allocated from the stack by smp_call_function_single(wait = 1) and the object can be passed an the IPI argument. Besides that, embedding the csd in an object is more error prone because the caller must take care of the serialization of the IPIs for this csd. 2) The user calls __smp_call_function_single(wait = 1) on a csd that is allocated on the stack. It's ok but smp_call_function_single() can do it as well and it already takes care of the allocation on the stack. Again it's more simple and less error prone. Therefore, using the underscore prepend API version with wait = 1 is a bad pattern and a sign that the caller can do safer and more simple. There was a single user of that which has just been converted. So lets remove this option to discourage further users. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24block: Stop abusing rq->csd.list in blk-softirqJan Kara1-6/+11
Abusing rq->csd.list for a list of requests to complete is rather ugly. We use rq->queuelist instead which is much cleaner. It is safe because queuelist is used by the block layer only for requests waiting to be submitted to a device. Thus it is unused when irq reports the request IO is finished. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-24block: Stop abusing csd.list for fifo_timeJan Kara2-8/+8
Block layer currently abuses rq->csd.list.next for storing fifo_time. That is a terrible hack and completely unnecessary as well. Union achieves the same space saving in a cleaner way. Signed-off-by: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jens Axboe <axboe@fb.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21blk-mq: support partial I/O completionsChristoph Hellwig1-32/+5
Add a new blk_mq_end_io_partial function to partially complete requests as needed by the SCSI layer. We do this by reusing blk_update_request to advance the bio instead of having a simplified version of it in the blk-mq code. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21blk-mq: merge blk_mq_insert_request and blk_mq_run_requestChristoph Hellwig4-47/+13
It's almost identical to blk_mq_insert_request, so fold the two into one slightly more generic function by making the flush special case a bit smarted. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-21blk-mq: remove blk_mq_alloc_rqChristoph Hellwig1-8/+2
There's only one caller, which is a straight wrapper and fits the naming scheme of the related functions a lot better. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-20Merge branch 'master' into for-nextJiri Kosina21-457/+484
2014-02-19treewide: Fix typo in Documentation/DocBookMasanari Iida2-2/+2
This patch fix spelling typo in Documentation/DocBook. It is because .html and .xml files are generated by make htmldocs, I have to fix a typo within the source files. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2014-02-18block: Substitute rcu_access_pointer() for rcu_dereference_raw()Paul E. McKenney2-2/+2
(Trivial patch.) If the code is looking at the RCU-protected pointer itself, but not dereferencing it, the rcu_dereference() functions can be downgraded to rcu_access_pointer(). This commit makes this downgrade in blkg_destroy() and ioc_destroy_icq(), both of which simply compare the RCU-protected pointer against another pointer with no dereferencing. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-18block: Use macros from compiler.h instead of __attribute__((...))Gideon Israel Dsouza3-6/+10
To increase compiler portability there are several macros defined in <linux/compiler.h> for various gcc __attribute((..)) constructs. I've made sure gcc these specific were replaced with the right macro and an #include <linux/compiler.h> was placed where needed. Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-14Merge branch 'for-linus' of git://git.kernel.dk/linux-blockLinus Torvalds11-158/+219
Pull block IO fixes from Jens Axboe: "Second round of updates and fixes for 3.14-rc2. Most of this stuff has been queued up for a while. The notable exception is the blk-mq changes, which are naturally a bit more in flux still. The pull request contains: - Two bug fixes for the new immutable vecs, causing crashes with raid or swap. From Kent. - Various blk-mq tweaks and fixes from Christoph. A fix for integrity bio's from Nic. - A few bcache fixes from Kent and Darrick Wong. - xen-blk{front,back} fixes from David Vrabel, Matt Rushton, Nicolas Swenson, and Roger Pau Monne. - Fix for a vec miscount with integrity vectors from Martin. - Minor annotations or fixes from Masanari Iida and Rashika Kheria. - Tweak to null_blk to do more normal FIFO processing of requests from Shlomo Pongratz. - Elevator switching bypass fix from Tejun. - Softlockup in blkdev_issue_discard() fix when !CONFIG_PREEMPT from me" * 'for-linus' of git://git.kernel.dk/linux-block: (31 commits) block: add cond_resched() to potentially long running ioctl discard loop xen-blkback: init persistent_purge_work work_struct blk-mq: pair blk_mq_start_request / blk_mq_requeue_request blk-mq: dont assume rq->errors is set when returning an error from ->queue_rq block: Fix cloning of discard/write same bios block: Fix type mismatch in ssize_t_blk_mq_tag_sysfs_show blk-mq: rework flush sequencing logic null_blk: use blk_complete_request and blk_mq_complete_request virtio_blk: use blk_mq_complete_request blk-mq: rework I/O completions fs: Add prototype declaration to appropriate header file include/linux/bio.h fs: Mark function as static in fs/bio-integrity.c block/null_blk: Fix completion processing from LIFO to FIFO block: Explicitly handle discard/write same segments block: Fix nr_vecs for inline integrity vectors blk-mq: Add bio_integrity setup to blk_mq_make_request blk-mq: initialize sg_reserved_size blk-mq: handle dma_drain_size blk-mq: divert __blk_put_request for MQ ops blk-mq: support at_head inserations for blk_execute_rq ...
2014-02-13cgroup: drop @skip_css from cgroup_taskset_for_each()Tejun Heo1-1/+1
If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching css. The intention of the interface is to make it easy to skip css's (cgroup_subsys_states) which already match the migration target; however, this is entirely unnecessary as migration taskset doesn't include tasks which are already in the target cgroup. Drop @skip_css from cgroup_taskset_for_each(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com>
2014-02-12block: add cond_resched() to potentially long running ioctl discard loopJens Axboe1-0/+8
When mkfs issues a full device discard and the device only supports discards of a smallish size, we can loop in blkdev_issue_discard() for a long time. If preempt isn't enabled, this can turn into a softlock situation and the kernel will start complaining. Add an explicit cond_resched() at the end of the loop to avoid that. Cc: stable@kernel.org Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-12cgroup: remove cgroup->nameTejun Heo1-4/+8
cgroup->name handling became quite complicated over time involving dedicated struct cgroup_name for RCU protection. Now that cgroup is on kernfs, we can drop all of it and simply use kernfs_name/path() and friends. Replace cgroup->name and all related code with kernfs name/path constructs. * Reimplement cgroup_name() and cgroup_path() as thin wrappers on top of kernfs counterparts, which involves semantic changes. pr_cont_cgroup_name() and pr_cont_cgroup_path() added. * cgroup->name handling dropped from cgroup_rename(). * All users of cgroup_name/path() updated to the new semantics. Users which were formatting the string just to printk them are converted to use pr_cont_cgroup_name/path() instead, which simplifies things quite a bit. As cgroup_name() no longer requires RCU read lock around it, RCU lockings which were protecting only cgroup_name() are removed. v2: Comment above oom_info_lock updated as suggested by Michal. v3: dummy_top doesn't have a kn associated and pr_cont_cgroup_name/path() ended up calling the matching kernfs functions with NULL kn leading to oops. Test for NULL kn and print "/" if so. This issue was reported by Fengguang Wu. v4: Rebased on top of 0ab02ca8f887 ("cgroup: protect modifications to cgroup_idr with cgroup_mutex"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
2014-02-11cgroup: update the meaning of cftype->max_write_lenTejun Heo2-7/+0
cftype->max_write_len is used to extend the maximum size of writes. It's interpreted in such a way that the actual maximum size is one less than the specified value. The default size is defined by CGROUP_LOCAL_BUFFER_SIZE. Its interpretation is quite confusing - its value is decremented by 1 and then compared for equality with max size, which means that the actual default size is CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars. There's no point in having a limit that low. Update its definition so that it means the actual string length sans termination and anything below PAGE_SIZE-1 is treated as PAGE_SIZE-1. .max_write_len for "release_agent" is updated to PATH_MAX-1 and cgroup_release_agent_write() is updated so that the redundant strlen() check is removed and it uses strlcpy() instead of strcpy(). .max_write_len initializations in blk-throttle.c and cfq-iosched.c are no longer necessary and removed. The one in cpuset is kept unchanged as it's an approximated value to begin with. This will also make transition to kernfs smoother. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
2014-02-11blk-mq: pair blk_mq_start_request / blk_mq_requeue_requestChristoph Hellwig1-23/+26
Make sure we have a proper pairing between starting and requeueing requests. Move the dma drain and REQ_END setup into blk_mq_start_request, and make sure blk_mq_requeue_request properly undoes them, giving us a pair of function to prepare and unprepare a request without leaving side effects. Together this ensures we always clean up properly after BLK_MQ_RQ_QUEUE_BUSY returns from ->queue_rq. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-11blk-mq: dont assume rq->errors is set when returning an error from ->queue_rqChristoph Hellwig1-1/+1
rq->errors never has been part of the communication protocol between drivers and the block stack and most drivers will not have initialized it. Return -EIO to upper layers when the driver returns BLK_MQ_RQ_QUEUE_ERROR unconditionally. If a driver want to return a different error it can easily do so by returning success after calling blk_mq_end_io itself. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10block: Fix type mismatch in ssize_t_blk_mq_tag_sysfs_showMasanari Iida1-1/+1
cppcheck detected following format string mismatch. [blk-mq-tag.c:201]: (warning) %u in format string (no. 1) requires 'unsigned int' but the argument type is 'int'. Change "cpu" from int to unsigned int, because the cpu never become minus value. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10blk-mq: rework flush sequencing logicChristoph Hellwig5-105/+72
Witch to using a preallocated flush_rq for blk-mq similar to what's done with the old request path. This allows us to set up the request properly with a tag from the actually allowed range and ->rq_disk as needed by some drivers. To make life easier we also switch to dynamic allocation of ->flush_rq for the old path. This effectively reverts most of "blk-mq: fix for flush deadlock" and "blk-mq: Don't reserve a tag for flush request" Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-10blk-mq: rework I/O completionsChristoph Hellwig3-24/+33
Rework I/O completions to work more like the old code path. blk_mq_end_io now stays out of the business of deferring completions to others CPUs and calling blk_mark_rq_complete. The latter is very important to allow completing requests that have timed out and thus are already marked completed, the former allows using the IPI callout even for driver specific completions instead of having to reimplement them. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-02-08cgroup: clean up cgroup_subsys names and initializationTejun Heo2-6/+4
cgroup_subsys is a bit messier than it needs to be. * The name of a subsys can be different from its internal identifier defined in cgroup_subsys.h. Most subsystems use the matching name but three - cpu, memory and perf_event - use different ones. * cgroup_subsys_id enums are postfixed with _subsys_id and each cgroup_subsys is postfixed with _subsys. cgroup.h is widely included throughout various subsystems, it doesn't and shouldn't have claim on such generic names which don't have any qualifier indicating that they belong to cgroup. * cgroup_subsys->subsys_id should always equal the matching cgroup_subsys_id enum; however, we require each controller to initialize it and then BUG if they don't match, which is a bit silly. This patch cleans up cgroup_subsys names and initialization by doing the followings. * cgroup_subsys_id enums are now postfixed with _cgrp_id, and each cgroup_subsys with _cgrp_subsys. * With the above, renaming subsys identifiers to match the userland visible names doesn't cause any naming conflicts. All non-matching identifiers are renamed to match the official names. cpu_cgroup -> cpu mem_cgroup -> memory perf -> perf_event * controllers no longer need to initialize ->subsys_id and ->name. They're generated in cgroup core and set automatically during boot. * Redundant cgroup_subsys declarations removed. * While updating BUG_ON()s in cgroup_init_early(), convert them to WARN()s. BUGging that early during boot is stupid - the kernel can't print anything, even through serial console and the trap handler doesn't even link stack frame properly for back-tracing. This patch doesn't introduce any behavior changes. v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs classid handling into core"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: "David S. Miller" <davem@davemloft.net> Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Ingo Molnar <mingo@redhat.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Thomas Graf <tgraf@suug.ch>
2014-02-08cgroup: drop module supportTejun Heo1-1/+0
With module supported dropped from net_prio, no controller is using cgroup module support. None of actual resource controllers can be built as a module and we aren't gonna add new controllers which don't control resources. This patch drops module support from cgroup. * cgroup_[un]load_subsys() and cgroup_subsys->module removed. * As there's no point in distinguishing IS_BUILTIN() and IS_MODULE(), cgroup_subsys.h now uses IS_ENABLED() directly. * enum cgroup_subsys_id now exactly matches the list of enabled controllers as ordered in cgroup_subsys.h. * cgroup_subsys[] is now a contiguously occupied array. Size specification is no longer necessary and dropped. * for_each_builtin_subsys() is removed and for_each_subsys() is updated to not require any locking. * module ref handling is removed from rebind_subsystems(). * Module related comments dropped. v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs classid handling into core"). v3: Added {} around the if (need_forkexit_callback) block in cgroup_post_fork() for readability as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>