user/sven/linux.git/block/elevator.c, branch v3.17

Revert "block: add __init to elv_register"

2014-06-22T22:34:11Z

This reverts commit b5097e956a4d2919ee248d6481e4204c5568ed5c. The original commit is buggy, we do use the registration functions at runtime, for instance when loading IO schedulers through sysfs. Reported-by: Damien Wyart

block: remove elv_abort_queue and blk_abort_flushes

2014-06-11T21:31:21Z

elv_abort_queue has no callers, and blk_abort_flushes is only called by elv_abort_queue. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: add __init to elv_register

2014-06-10T19:13:11Z

elv_register is only called by elevator init functions: __init cfq_init __init deadline_init __init noop_init Cc: Andrew Morton Signed-off-by: Fabian Frederick Signed-off-by: Jens Axboe

block: fix regression with block enabled tagging

2014-04-10T03:54:06Z

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: [] 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:[] [] 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: [] scsi_request_fn+0xf2/0x510 [] __blk_run_queue+0x37/0x50 [] blk_execute_rq_nowait+0xb3/0x130 [] blk_execute_rq+0x64/0xf0 [] ? bit_waitqueue+0xd0/0xd0 [] scsi_execute+0xe5/0x180 [] scsi_execute_req_flags+0x9a/0x110 [] sd_spinup_disk+0x94/0x460 [sd_mod] [] ? __unmap_hugepage_range+0x200/0x2f0 [] sd_revalidate_disk+0xaa/0x3f0 [sd_mod] [] sd_probe_async+0xd8/0x200 [sd_mod] [] async_run_entry_fn+0x3f/0x140 [] process_one_work+0x175/0x410 [] worker_thread+0x123/0x400 [] ? manage_workers+0x160/0x160 [] kthread+0xce/0xf0 [] ? kthread_freezable_should_stop+0x70/0x70 [] ret_from_fork+0x7c/0xb0 [] ? 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 [] blk_queue_start_tag+0x90/0x150 RSP CR2: ffff88046c6c9e80 Martin bisected and found this to be the problem patch; commit 6d113398dcf4dfcd9787a4ead738b186f7b7ff0f Author: Jan Kara 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 Tested-by: Benjamin Herrenschmidt Signed-off-by: Jens Axboe

block: Abstract out bvec iterator

2013-11-24T06:33:47Z

Immutable biovecs are going to require an explicit iterator. To implement immutable bvecs, a later patch is going to add a bi_bvec_done member to this struct; for now, this patch effectively just renames things. Signed-off-by: Kent Overstreet Cc: Jens Axboe Cc: Geert Uytterhoeven Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: "Ed L. Cashin" Cc: Nick Piggin Cc: Lars Ellenberg Cc: Jiri Kosina Cc: Matthew Wilcox Cc: Geoff Levand Cc: Yehuda Sadeh Cc: Sage Weil Cc: Alex Elder Cc: ceph-devel@vger.kernel.org Cc: Joshua Morris Cc: Philip Kelleher Cc: Rusty Russell Cc: "Michael S. Tsirkin" Cc: Konrad Rzeszutek Wilk Cc: Jeremy Fitzhardinge Cc: Neil Brown Cc: Alasdair Kergon Cc: Mike Snitzer Cc: dm-devel@redhat.com Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: linux390@de.ibm.com Cc: Boaz Harrosh Cc: Benny Halevy Cc: "James E.J. Bottomley" Cc: Greg Kroah-Hartman Cc: "Nicholas A. Bellinger" Cc: Alexander Viro Cc: Chris Mason Cc: "Theodore Ts'o" Cc: Andreas Dilger Cc: Jaegeuk Kim Cc: Steven Whitehouse Cc: Dave Kleikamp Cc: Joern Engel Cc: Prasad Joshi Cc: Trond Myklebust Cc: KONISHI Ryusuke Cc: Mark Fasheh Cc: Joel Becker Cc: Ben Myers Cc: xfs@oss.sgi.com Cc: Steven Rostedt Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Len Brown Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: Herton Ronaldo Krzesinski Cc: Ben Hutchings Cc: Andrew Morton Cc: Guo Chao Cc: Tejun Heo Cc: Asai Thambi S P Cc: Selvan Mani Cc: Sam Bradshaw Cc: Wei Yongjun Cc: "Roger Pau Monné" Cc: Jan Beulich Cc: Stefano Stabellini Cc: Ian Campbell Cc: Sebastian Ott Cc: Christian Borntraeger Cc: Minchan Kim Cc: Jiang Liu Cc: Nitin Gupta Cc: Jerome Marchand Cc: Joe Perches Cc: Peng Tao Cc: Andy Adamson Cc: fanchaoting Cc: Jie Liu Cc: Sunil Mushran Cc: "Martin K. Petersen" Cc: Namjae Jeon Cc: Pankaj Kumar Cc: Dan Magenheimer Cc: Mel Gorman 6

elevator: acquire q->sysfs_lock in elevator_change()

2013-11-08T16:00:13Z

Add locking of q->sysfs_lock into elevator_change() (an exported function) to ensure it is held to protect q->elevator from elevator_init(), even if elevator_change() is called from non-sysfs paths. sysfs path (elv_iosched_store) uses __elevator_change(), non-locking version, as the lock is already taken by elv_iosched_store(). Signed-off-by: Tomoki Sekiyama Signed-off-by: Jens Axboe

elevator: Fix a race in elevator switching and md device initialization

2013-11-08T16:00:08Z

The soft lockup below happens at the boot time of the system using dm multipath and the udev rules to switch scheduler. [ 356.127001] BUG: soft lockup - CPU#3 stuck for 22s! [sh:483] [ 356.127001] RIP: 0010:[] [] lock_timer_base.isra.35+0x1d/0x50 ... [ 356.127001] Call Trace: [ 356.127001] [] try_to_del_timer_sync+0x20/0x70 [ 356.127001] [] ? kmem_cache_alloc_node_trace+0x20a/0x230 [ 356.127001] [] del_timer_sync+0x52/0x60 [ 356.127001] [] cfq_exit_queue+0x32/0xf0 [ 356.127001] [] elevator_exit+0x2f/0x50 [ 356.127001] [] elevator_change+0xf1/0x1c0 [ 356.127001] [] elv_iosched_store+0x20/0x50 [ 356.127001] [] queue_attr_store+0x59/0xb0 [ 356.127001] [] sysfs_write_file+0xc6/0x140 [ 356.127001] [] vfs_write+0xbd/0x1e0 [ 356.127001] [] SyS_write+0x49/0xa0 [ 356.127001] [] system_call_fastpath+0x16/0x1b This is caused by a race between md device initialization by multipathd and shell script to switch the scheduler using sysfs. - multipathd: SyS_ioctl -> do_vfs_ioctl -> dm_ctl_ioctl -> ctl_ioctl -> table_load -> dm_setup_md_queue -> blk_init_allocated_queue -> elevator_init q->elevator = elevator_alloc(q, e); // not yet initialized - sh -c 'echo deadline > /sys/$DEVPATH/queue/scheduler': elevator_switch (in the call trace above) struct elevator_queue *old = q->elevator; q->elevator = elevator_alloc(q, new_e); elevator_exit(old); // lockup! (*) - multipathd: (cont.) err = e->ops.elevator_init_fn(q); // init fails; q->elevator is modified (*) When del_timer_sync() is called, lock_timer_base() will loop infinitely while timer->base == NULL. In this case, as timer will never initialized, it results in lockup. This patch introduces acquisition of q->sysfs_lock around elevator_init() into blk_init_allocated_queue(), to provide mutual exclusion between initialization of the q->scheduler and switching of the scheduler. This should fix this bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=902012 Signed-off-by: Tomoki Sekiyama Signed-off-by: Jens Axboe

block: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...)

2013-09-11T19:22:03Z

Use the helper function instead of __GFP_ZERO. Signed-off-by: Joe Perches Signed-off-by: Jens Axboe

elevator: Fix a race in elevator switching

2013-07-03T11:25:24Z

There's a race between elevator switching and normal io operation. Because the allocation of struct elevator_queue and struct elevator_data don't in a atomic operation.So there are have chance to use NULL ->elevator_data. For example: Thread A: Thread B blk_queu_bio elevator_switch spin_lock_irq(q->queue_block) elevator_alloc elv_merge elevator_init_fn Because call elevator_alloc, it can't hold queue_lock and the ->elevator_data is NULL.So at the same time, threadA call elv_merge and nedd some info of elevator_data.So the crash happened. Move the elevator_alloc into func elevator_init_fn, it make the operations in a atomic operation. Using the follow method can easy reproduce this bug 1:dd if=/dev/sdb of=/dev/null 2:while true;do echo noop > scheduler;echo deadline > scheduler;done The test method also use this method. Signed-off-by: Jianpeng Ma Signed-off-by: Jens Axboe

block: implement runtime pm strategy

2013-03-23T04:22:15Z

When a request is added: If device is suspended or is suspending and the request is not a PM request, resume the device. When the last request finishes: Call pm_runtime_mark_last_busy(). When pick a request: If device is resuming/suspending, then only PM request is allowed to go. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming Signed-off-by: Aaron Lu Acked-by: Alan Stern Signed-off-by: Jens Axboe