Commit Graph

150 Commits

Author SHA1 Message Date
Linus Torvalds 033d9959ed Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue changes from Tejun Heo:
 "This is workqueue updates for v3.7-rc1.  A lot of activities this
  round including considerable API and behavior cleanups.

   * delayed_work combines a timer and a work item.  The handling of the
     timer part has always been a bit clunky leading to confusing
     cancelation API with weird corner-case behaviors.  delayed_work is
     updated to use new IRQ safe timer and cancelation now works as
     expected.

   * Another deficiency of delayed_work was lack of the counterpart of
     mod_timer() which led to cancel+queue combinations or open-coded
     timer+work usages.  mod_delayed_work[_on]() are added.

     These two delayed_work changes make delayed_work provide interface
     and behave like timer which is executed with process context.

   * A work item could be executed concurrently on multiple CPUs, which
     is rather unintuitive and made flush_work() behavior confusing and
     half-broken under certain circumstances.  This problem doesn't
     exist for non-reentrant workqueues.  While non-reentrancy check
     isn't free, the overhead is incurred only when a work item bounces
     across different CPUs and even in simulated pathological scenario
     the overhead isn't too high.

     All workqueues are made non-reentrant.  This removes the
     distinction between flush_[delayed_]work() and
     flush_[delayed_]_work_sync().  The former is now as strong as the
     latter and the specified work item is guaranteed to have finished
     execution of any previous queueing on return.

   * In addition to the various bug fixes, Lai redid and simplified CPU
     hotplug handling significantly.

   * Joonsoo introduced system_highpri_wq and used it during CPU
     hotplug.

  There are two merge commits - one to pull in IRQ safe timer from
  tip/timers/core and the other to pull in CPU hotplug fixes from
  wq/for-3.6-fixes as Lai's hotplug restructuring depended on them."

Fixed a number of trivial conflicts, but the more interesting conflicts
were silent ones where the deprecated interfaces had been used by new
code in the merge window, and thus didn't cause any real data conflicts.

Tejun pointed out a few of them, I fixed a couple more.

* 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits)
  workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending()
  workqueue: use cwq_set_max_active() helper for workqueue_set_max_active()
  workqueue: introduce cwq_set_max_active() helper for thaw_workqueues()
  workqueue: remove @delayed from cwq_dec_nr_in_flight()
  workqueue: fix possible stall on try_to_grab_pending() of a delayed work item
  workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback()
  workqueue: use __cpuinit instead of __devinit for cpu callbacks
  workqueue: rename manager_mutex to assoc_mutex
  workqueue: WORKER_REBIND is no longer necessary for idle rebinding
  workqueue: WORKER_REBIND is no longer necessary for busy rebinding
  workqueue: reimplement idle worker rebinding
  workqueue: deprecate __cancel_delayed_work()
  workqueue: reimplement cancel_delayed_work() using try_to_grab_pending()
  workqueue: use mod_delayed_work() instead of __cancel + queue
  workqueue: use irqsafe timer for delayed_work
  workqueue: clean up delayed_work initializers and add missing one
  workqueue: make deferrable delayed_work initializer names consistent
  workqueue: cosmetic whitespace updates for macro definitions
  workqueue: deprecate system_nrt[_freezable]_wq
  workqueue: deprecate flush[_delayed]_work_sync()
  ...
2012-10-02 09:54:49 -07:00
Tejun Heo 3b07e9ca26 workqueue: deprecate system_nrt[_freezable]_wq
system_nrt[_freezable]_wq are now spurious.  Mark them deprecated and
convert all users to system[_freezable]_wq.

If you're cc'd and wondering what's going on: Now all workqueues are
non-reentrant, so there's no reason to use system_nrt[_freezable]_wq.
Please use system[_freezable]_wq instead.

This patch doesn't make any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-By: Lai Jiangshan <laijs@cn.fujitsu.com>

Cc: Jens Axboe <axboe@kernel.dk>
Cc: David Airlie <airlied@linux.ie>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: David Howells <dhowells@redhat.com>
2012-08-20 14:51:24 -07:00
Tejun Heo 41f63c5359 workqueue: use mod_delayed_work() instead of cancel + queue
Convert delayed_work users doing cancel_delayed_work() followed by
queue_delayed_work() to mod_delayed_work().

Most conversions are straight-forward.  Ones worth mentioning are,

* drivers/edac/edac_mc.c: edac_mc_workq_setup() converted to always
  use mod_delayed_work() and cancel loop in
  edac_mc_reset_delay_period() is dropped.

* drivers/platform/x86/thinkpad_acpi.c: No need to remember whether
  watchdog is active or not.  @fan_watchdog_active and related code
  dropped.

* drivers/power/charger-manager.c: Seemingly a lot of
  delayed_work_pending() abuse going on here.
  [delayed_]work_pending() are unsynchronized and racy when used like
  this.  I converted one instance in fullbatt_handler().  Please
  conver the rest so that it invokes workqueue APIs for the intended
  target state rather than trying to game work item pending state
  transitions.  e.g. if timer should be modified - call
  mod_delayed_work(), canceled - call cancel_delayed_work[_sync]().

* drivers/thermal/thermal_sys.c: thermal_zone_device_set_polling()
  simplified.  Note that round_jiffies() calls in this function are
  meaningless.  round_jiffies() work on absolute jiffies not delta
  delay used by delayed_work.

v2: Tomi pointed out that __cancel_delayed_work() users can't be
    safely converted to mod_delayed_work().  They could be calling it
    from irq context and if that happens while delayed_work_timer_fn()
    is running, it could deadlock.  __cancel_delayed_work() users are
    dropped.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Doug Thompson <dougthompson@xmission.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Roland Dreier <roland@kernel.org>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
2012-08-13 16:27:37 -07:00
Jianpeng Ma 0676806707 block: Don't use static to define "void *p" in show_partition_start()
I met a odd prblem:read /proc/partitions may return zero.

I wrote a file test.c:
int main()
{
	char buff[4096];
	int ret;
	int fd;
	printf("pid=%d\n",getpid());
	while (1) {
		fd = open("/proc/partitions", O_RDONLY);
		if (fd < 0) {
			printf("open error %s\n", strerror(errno));
			return 0;
		}
		ret = read(fd, buff, 4096);
		if (ret <= 0)
			printf("ret=%d, %s, %ld\n", ret,
				strerror(errno), lseek(fd,0,SEEK_CUR));
		close(fd);
	}
	exit(0);
}

You can reproduce by:
1:while true;do cat /proc/partitions > /dev/null ;done
2:./test

I reviewed the code and found:

>> static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
>> {
>> 	static void *p;
>>
>> 	p = disk_seqf_start(seqf, pos);
>> 	if (!IS_ERR_OR_NULL(p) && !*pos)
>> 		seq_puts(seqf, "major minor  #blocks  name\n\n");
>> 	return p;
>> }
		test								cat /proc/partitions
	p = disk_seqf_start()(Not NULL)
									p = disk_seqf_start()(NULL because pos)
	if (!IS_ERR_OR_NULL(p) && !*pos)

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-08-03 10:42:00 +02:00
Vivek Goyal c83f6bf98d block: add partition resize function to blkpg ioctl
Add a new operation code (BLKPG_RESIZE_PARTITION) to the BLKPG ioctl that
allows altering the size of an existing partition, even if it is currently
in use.

This patch converts hd_struct->nr_sects into sequence counter because
One might extend a partition while IO is happening to it and update of
nr_sects can be non-atomic on 32bit machines with 64bit sector_t. This
can lead to issues like reading inconsistent size of a partition. Sequence
counter have been used so that readers don't have to take bdev mutex lock
as we call sector_in_part() very frequently.

Now all the access to hd_struct->nr_sects should happen using sequence
counter read/update helper functions part_nr_sects_read/part_nr_sects_write.
There is one exception though, set_capacity()/get_capacity(). I think
theoritically race should exist there too but this patch does not
modify set_capacity()/get_capacity() due to sheer number of call sites
and I am afraid that change might break something. I have left that as a
TODO item. We can handle it later if need be. This patch does not introduce
any new races as such w.r.t set_capacity()/get_capacity().

v2: Add CONFIG_LBDAF test to UP preempt case as suggested by Phillip.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Phillip Susi <psusi@ubuntu.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-08-01 12:24:18 +02:00
Tejun Heo 05c69d298c block: fix buffer overflow when printing partition UUIDs
6d1d8050b4 "block, partition: add partition_meta_info to hd_struct"
added part_unpack_uuid() which assumes that the passed in buffer has
enough space for sprintfing "%pU" - 37 characters including '\0'.

Unfortunately, b5af921ec0 "init: add support for root devices
specified by partition UUID" supplied 33 bytes buffer to the function
leading to the following panic with stackprotector enabled.

  Kernel panic - not syncing: stack-protector: Kernel stack corrupted in: ffffffff81b14c7e

  [<ffffffff815e226b>] panic+0xba/0x1c6
  [<ffffffff81b14c7e>] ? printk_all_partitions+0x259/0x26xb
  [<ffffffff810566bb>] __stack_chk_fail+0x1b/0x20
  [<ffffffff81b15c7e>] printk_all_paritions+0x259/0x26xb
  [<ffffffff81aedfe0>] mount_block_root+0x1bc/0x27f
  [<ffffffff81aee0fa>] mount_root+0x57/0x5b
  [<ffffffff81aee23b>] prepare_namespace+0x13d/0x176
  [<ffffffff8107eec0>] ? release_tgcred.isra.4+0x330/0x30
  [<ffffffff81aedd60>] kernel_init+0x155/0x15a
  [<ffffffff81087b97>] ? schedule_tail+0x27/0xb0
  [<ffffffff815f4d24>] kernel_thread_helper+0x5/0x10
  [<ffffffff81aedc0b>] ? start_kernel+0x3c5/0x3c5
  [<ffffffff815f4d20>] ? gs_change+0x13/0x13

Increase the buffer size, remove the dangerous part_unpack_uuid() and
use snprintf() directly from printk_all_partitions().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Szymon Gruszczynski <sz.gruszczynski@googlemail.com>
Cc: Will Drewry <wad@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-05-15 08:22:04 +02:00
Alan Stern 62d3c5439c Block: use a freezable workqueue for disk-event polling
This patch (as1519) fixes a bug in the block layer's disk-events
polling.  The polling is done by a work routine queued on the
system_nrt_wq workqueue.  Since that workqueue isn't freezable, the
polling continues even in the middle of a system sleep transition.

Obviously, polling a suspended drive for media changes and such isn't
a good thing to do; in the case of USB mass-storage devices it can
lead to real problems requiring device resets and even re-enumeration.

The patch fixes things by creating a new system-wide, non-reentrant,
freezable workqueue and using it for disk-events polling.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: <stable@kernel.org>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-03-02 10:51:00 +01:00
Stanislaw Gruszka 9f53d2fe81 block: fix __blkdev_get and add_disk race condition
The following situation might occur:

__blkdev_get:			add_disk:

				register_disk()
get_gendisk()

disk_block_events()
	disk->ev == NULL

				disk_add_events()

__disk_unblock_events()
	disk->ev != NULL
	--ev->block

Then we unblock events, when they are suppose to be blocked. This can
trigger events related block/genhd.c warnings, but also can crash in
sd_check_events() or other places.

I'm able to reproduce crashes with the following scripts (with
connected usb dongle as sdb disk).

<snip>
DEV=/dev/sdb
ENABLE=/sys/bus/usb/devices/1-2/bConfigurationValue

function stop_me()
{
	for i in `jobs -p` ; do kill $i 2> /dev/null ; done
	exit
}

trap stop_me SIGHUP SIGINT SIGTERM

for ((i = 0; i < 10; i++)) ; do
	while true; do fdisk -l $DEV  2>&1 > /dev/null ; done &
done

while true ; do
echo 1 > $ENABLE
sleep 1
echo 0 > $ENABLE
done
</snip>

I use the script to verify patch fixing oops in sd_revalidate_disk
http://marc.info/?l=linux-scsi&m=132935572512352&w=2
Without Jun'ichi Nomura patch titled "Fix NULL pointer dereference in
sd_revalidate_disk" or this one, script easily crash kernel within
a few seconds. With both patches applied I do not observe crash.
Unfortunately after some time (dozen of minutes), script will hung in:

[ 1563.906432]  [<c08354f5>] schedule_timeout_uninterruptible+0x15/0x20
[ 1563.906437]  [<c04532d5>] msleep+0x15/0x20
[ 1563.906443]  [<c05d60b2>] blk_drain_queue+0x32/0xd0
[ 1563.906447]  [<c05d6e00>] blk_cleanup_queue+0xd0/0x170
[ 1563.906454]  [<c06d278f>] scsi_free_queue+0x3f/0x60
[ 1563.906459]  [<c06d7e6e>] __scsi_remove_device+0x6e/0xb0
[ 1563.906463]  [<c06d4aff>] scsi_forget_host+0x4f/0x60
[ 1563.906468]  [<c06cd84a>] scsi_remove_host+0x5a/0xf0
[ 1563.906482]  [<f7f030fb>] quiesce_and_remove_host+0x5b/0xa0 [usb_storage]
[ 1563.906490]  [<f7f03203>] usb_stor_disconnect+0x13/0x20 [usb_storage]

Anyway I think this patch is some step forward.

As drawback, I do not teardown on sysfs file create error, because I do
not know how to nullify disk->ev (since it can be used). However add_disk
error handling practically does not exist too, and things will work
without this sysfs file, except events will not be exported to user
space.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2012-03-02 10:44:17 +01:00
Linus Torvalds b3c9dd182e Merge branch 'for-3.3/core' of git://git.kernel.dk/linux-block
* 'for-3.3/core' of git://git.kernel.dk/linux-block: (37 commits)
  Revert "block: recursive merge requests"
  block: Stop using macro stubs for the bio data integrity calls
  blockdev: convert some macros to static inlines
  fs: remove unneeded plug in mpage_readpages()
  block: Add BLKROTATIONAL ioctl
  block: Introduce blk_set_stacking_limits function
  block: remove WARN_ON_ONCE() in exit_io_context()
  block: an exiting task should be allowed to create io_context
  block: ioc_cgroup_changed() needs to be exported
  block: recursive merge requests
  block, cfq: fix empty queue crash caused by request merge
  block, cfq: move icq creation and rq->elv.icq association to block core
  block, cfq: restructure io_cq creation path for io_context interface cleanup
  block, cfq: move io_cq exit/release to blk-ioc.c
  block, cfq: move icq cache management to block core
  block, cfq: move io_cq lookup to blk-ioc.c
  block, cfq: move cfqd->icq_list to request_queue and add request->elv.icq
  block, cfq: reorganize cfq_io_context into generic and cfq specific parts
  block: remove elevator_queue->ops
  block: reorder elevator switch sequence
  ...

Fix up conflicts in:
 - block/blk-cgroup.c
	Switch from can_attach_task to can_attach
 - block/cfq-iosched.c
	conflict with now removed cic index changes (we now use q->id instead)
2012-01-15 12:24:45 -08:00
Al Viro ece2ccb668 Merge branches 'vfsmount-guts', 'umode_t' and 'partitions' into Z 2012-01-06 23:15:54 -05:00
Al Viro 2c9ede55ec switch device_get_devnode() and ->devnode() to umode_t *
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:55 -05:00
Al Viro ff01bb4832 fs: move code out of buffer.c
Move invalidate_bdev, block_sync_page into fs/block_dev.c.  Export
kill_bdev as well, so brd doesn't have to open code it.  Reduce
buffer_head.h requirement accordingly.

Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving.  The small comment replacing it says enough.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:07 -05:00
Al Viro 4752bc309b make register_disk() static
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2012-01-03 22:54:05 -05:00
Tejun Heo 09ac46c429 block: misc updates to blk_get_queue()
* blk_get_queue() is peculiar in that it returns 0 on success and 1 on
  failure instead of 0 / -errno or boolean.  Update it such that it
  returns %true on success and %false on failure.

* Make sure the caller checks for the return value.

* Separate out __blk_get_queue() which doesn't check whether @q is
  dead and put it in blk.h.  This will be used later.

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-12-14 00:33:38 +01:00
Tejun Heo d0985394e7 block: Revert "[SCSI] genhd: add a new attribute "alias" in gendisk"
This reverts commit a72c5e5eb7.

The commit introduced alias for block devices which is intended to be
used during logging although actual usage hasn't been committed yet.
This approach adds very limited benefit (raw log might be easier to
follow) which can be trivially implemented in userland but has a lot
of problems.

It is much worse than netif renames because it doesn't rename the
actual device but just adds conveninence name which isn't used
universally or enforced.  Everything internal including device lookup
and sysfs still uses the internal name and nothing prevents two
devices from using conflicting alias - ie. sda can have sdb as its
alias.

This has been nacked by people working on device driver core, block
layer and kernel-userland interface and shouldn't have been
upstreamed.  Revert it.

 http://thread.gmane.org/gmane.linux.kernel/1155104
 http://thread.gmane.org/gmane.linux.scsi/68632
 http://thread.gmane.org/gmane.linux.scsi/69776

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
 Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Nao Nishijima <nao.nishijima.xt@hitachi.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-11-10 09:03:55 +01:00
Linus Torvalds 3d0a8d10cf Merge branch 'for-3.2/drivers' of git://git.kernel.dk/linux-block
* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits)
  virtio-blk: use ida to allocate disk index
  hpsa: add small delay when using PCI Power Management to reset for kump
  cciss: add small delay when using PCI Power Management to reset for kump
  xen/blkback: Fix two races in the handling of barrier requests.
  xen/blkback: Check for proper operation.
  xen/blkback: Fix the inhibition to map pages when discarding sector ranges.
  xen/blkback: Report VBD_WSECT (wr_sect) properly.
  xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests.
  xen-blkfront: plug device number leak in xlblk_init() error path
  xen-blkfront: If no barrier or flush is supported, use invalid operation.
  xen-blkback: use kzalloc() in favor of kmalloc()+memset()
  xen-blkback: fixed indentation and comments
  xen-blkfront: fix a deadlock while handling discard response
  xen-blkfront: Handle discard requests.
  xen-blkback: Implement discard requests ('feature-discard')
  xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
  drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()
  drivers/block/loop.c: emit uevent on auto release
  drivers/block/cpqarray.c: use pci_dev->revision
  loop: always allow userspace partitions and optionally support automatic scanning
  ...

Fic up trivial header file includsion conflict in drivers/block/loop.c
2011-11-04 17:22:14 -07:00
Linus Torvalds b4fdcb02f1 Merge branch 'for-3.2/core' of git://git.kernel.dk/linux-block
* 'for-3.2/core' of git://git.kernel.dk/linux-block: (29 commits)
  block: don't call blk_drain_queue() if elevator is not up
  blk-throttle: use queue_is_locked() instead of lockdep_is_held()
  blk-throttle: Take blkcg->lock while traversing blkcg->policy_list
  blk-throttle: Free up policy node associated with deleted rule
  block: warn if tag is greater than real_max_depth.
  block: make gendisk hold a reference to its queue
  blk-flush: move the queue kick into
  blk-flush: fix invalid BUG_ON in blk_insert_flush
  block: Remove the control of complete cpu from bio.
  block: fix a typo in the blk-cgroup.h file
  block: initialize the bounce pool if high memory may be added later
  block: fix request_queue lifetime handling by making blk_queue_cleanup() properly shutdown
  block: drop @tsk from attempt_plug_merge() and explain sync rules
  block: make get_request[_wait]() fail if queue is dead
  block: reorganize throtl_get_tg() and blk_throtl_bio()
  block: reorganize queue draining
  block: drop unnecessary blk_get/put_queue() in scsi_cmd_ioctl() and blk_get_tg()
  block: pass around REQ_* flags instead of broken down booleans during request alloc/free
  block: move blk_throtl prototypes to block/blk.h
  block: fix genhd refcounting in blkio_policy_parse_and_set()
  ...

Fix up trivial conflicts due to "mddev_t" -> "struct mddev" conversion
and making the request functions be of type "void" instead of "int" in
 - drivers/md/{faulty.c,linear.c,md.c,md.h,multipath.c,raid0.c,raid1.c,raid10.c,raid5.c}
 - drivers/staging/zram/zram_drv.c
2011-11-04 17:06:58 -07:00
Tejun Heo 523e1d399c block: make gendisk hold a reference to its queue
The following command sequence triggers an oops.

# mount /dev/sdb1 /mnt
# echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete
# umount /mnt

 general protection fault: 0000 [#1] PREEMPT SMP
 CPU 2
 Modules linked in:

 Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs
 RIP: 0010:[<ffffffff810d0879>]  [<ffffffff810d0879>] __lock_acquire+0x389/0x1d60
...
 Call Trace:
  [<ffffffff810d2845>] lock_acquire+0x95/0x140
  [<ffffffff81aed87b>] _raw_spin_lock+0x3b/0x50
  [<ffffffff811573bc>] bdi_lock_two+0x5c/0x70
  [<ffffffff811c2f6c>] bdev_inode_switch_bdi+0x4c/0xf0
  [<ffffffff811c3fcb>] __blkdev_put+0x11b/0x1d0
  [<ffffffff811c4010>] __blkdev_put+0x160/0x1d0
  [<ffffffff811c40df>] blkdev_put+0x5f/0x190
  [<ffffffff8118f18d>] kill_block_super+0x4d/0x80
  [<ffffffff8118f4a5>] deactivate_locked_super+0x45/0x70
  [<ffffffff8119003a>] deactivate_super+0x4a/0x70
  [<ffffffff811ac4ad>] mntput_no_expire+0xed/0x130
  [<ffffffff811acf2e>] sys_umount+0x7e/0x3a0
  [<ffffffff81aeeeab>] system_call_fastpath+0x16/0x1b

This is because bdev holds on to disk but disk doesn't pin the
associated queue.  If a SCSI device is removed while the device is
still open, the sdev puts the base reference to the queue on release.
When the bdev is finally released, the associated queue is already
gone along with the bdi and bdev_inode_switch_bdi() ends up
dereferencing already freed bdi.

Even if it were not for this bug, disk not holding onto the associated
queue is very unusual and error-prone.

Fix it by making add_disk() take an extra reference to its queue and
put it on disk_release() and ensuring that disk and its fops owner are
put in that order after all accesses to the disk and queue are
complete.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2011-10-19 14:31:07 +02:00
Nao Nishijima a72c5e5eb7 [SCSI] genhd: add a new attribute "alias" in gendisk
This patch allows the user to set an "alias" of the disk via sysfs interface.

This patch only adds a new attribute "alias" in gendisk structure.
To show the alias instead of the device name in kernel messages,
we need to revise printk messages and use alias_name() in them.

Example:
(current) printk("disk name is %s\n", disk->disk_name);
(new)     printk("disk name is %s\n", alias_name(disk));

Users can use alphabets, numbers, '-' and '_' in "alias" attribute. A disk can
have an "alias" which length is up to 255 bytes. This attribute is write-once.

Suggested-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Suggested-by: Jon Masters <jcm@redhat.com>
Signed-off-by: Nao Nishijima <nao.nishijima.xt@hitachi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2011-08-29 00:16:19 -07:00
Tejun Heo d27769ec3d block: add GENHD_FL_NO_PART_SCAN
There are cases where suppressing partition scan is useful - e.g. for
lo devices and pseudo SATA devices which advertise to be a disk but
get upset on partition scan (some port multiplier control devices show
such behavior).

This patch adds GENHD_FL_NO_PART_SCAN which suppresses partition scan
regardless of the number of possible partitions.  disk_partitionable()
is renamed to disk_part_scan_enabled() as suppressing partition scan
doesn't imply the device can't be partitioned using
BLKPG_ADD/DEL_PARTITION calls from userland.  show_partition() now
directly tests disk_max_parts() to maintain backward-compatibility.

-v2: Updated to make it clear that only partition scan is suppressed
     not partitioning itself as suggested by Kay Sievers.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-23 20:01:04 +02:00
Herbert Poetzl f95fe9cfb4 block/genhd.c: remove useless cast in diskstats_show()
Remove the (unsigned long long) cast in diskstats_show() and adjusts the
seq_printf() format string to 'unsigned long'

diskstats_show() uses part_stat_read() to get the stats, which either
accesses the specified field in the struct disk_stats directly (non SMP)
or sums up the per CPU values in a variable of the same type as the field,
so in any case the result will have the same type and range as the
specified field which for all disk_stats entries is unsigned long

Also, for unsigned long ranges the output of %lu should be identical to
the one of %llu, so no change in the actual proc entry contents.

Signed-off-by: Herbert Poetzl <herbert@13thfloor.at>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-08-02 12:43:50 +02:00
Linus Torvalds 096a705bbc Merge branch 'for-3.1/core' of git://git.kernel.dk/linux-block
* 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits)
  block: strict rq_affinity
  backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu
  block: fix patch import error in max_discard_sectors check
  block: reorder request_queue to remove 64 bit alignment padding
  CFQ: add think time check for group
  CFQ: add think time check for service tree
  CFQ: move think time check variables to a separate struct
  fixlet: Remove fs_excl from struct task.
  cfq: Remove special treatment for metadata rqs.
  block: document blk_plug list access
  block: avoid building too big plug list
  compat_ioctl: fix make headers_check regression
  block: eliminate potential for infinite loop in blkdev_issue_discard
  compat_ioctl: fix warning caused by qemu
  block: flush MEDIA_CHANGE from drivers on close(2)
  blk-throttle: Make total_nr_queued unsigned
  block: Add __attribute__((format(printf...) and fix fallout
  fs/partitions/check.c: make local symbols static
  block:remove some spare spaces in genhd.c
  block:fix the comment error in blkdev.h
  ...
2011-07-25 10:33:36 -07:00
Lai Jiangshan 57bdfbf9ee block,rcu: Convert call_rcu(disk_free_ptbl_rcu_cb) to kfree_rcu()
The rcu callback disk_free_ptbl_rcu_cb() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(disk_free_ptbl_rcu_cb).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
2011-07-20 14:10:13 -07:00
Tejun Heo 85ef06d1d2 block: flush MEDIA_CHANGE from drivers on close(2)
Currently, only open(2) is defined as the 'clearing' point.  It has
two roles - first, it's an acknowledgement from userland indicating
that the event has been received and kernel can clear pending states
and proceed to generate more events.  Secondly, it's passed on to
device drivers as a hint indicating that a synchronization point has
been reached and it might want to take a deeper look at the device.

The latter currently is only used by sr which uses two different
mechanisms - GET_EVENT_MEDIA_STATUS_NOTIFICATION and TEST_UNIT_READY
to discover events, where the former is lighter weight and safe to be
used repeatedly but may not provide full coverage.  Among other
things, GET_EVENT can't detect media removal while TUR can.

This patch makes close(2) - blkdev_put() - indicate clearing hint for
MEDIA_CHANGE to drivers.  disk_check_events() is renamed to
disk_flush_events() and updated to take @mask for events to flush
which is or'd to ev->clearing and will be passed to the driver on the
next ->check_events() invocation.

This change makes sr generate MEDIA_CHANGE when media is ejected from
userland - e.g. with eject(1).

Note: Given the current usage, it seems @clearing hint is needlessly
complex.  disk_clear_events() can simply clear all events and the hint
can be boolean @flush.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-01 16:17:47 +02:00
Jens Axboe 04bf7869ca Merge branch 'for-linus' into for-3.1/core
Conflicts:
	block/blk-throttle.c
	block/cfq-iosched.c

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-07-01 16:17:13 +02:00
Wanlong Gao 9f5e486550 block:remove some spare spaces in genhd.c
Remove the end-of-line spaces in genhd.c.

Signed-off-by: Wanlong Gao <wanlong.gao@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-06-13 10:45:43 +02:00
Tejun Heo fdd514e16b block: make disk_block_events() properly wait for work cancellation
disk_block_events() should guarantee that the event work is not in
flight on return and once blocked it shouldn't issue further
cancellations.

Because there was no synchronization between the first blocker doing
cancel_delayed_work_sync() and the following blockers, the following
blockers could finish before cancellation was complete, which broke
both guarantees - event work could be in flight and cancellation could
happen after return.

This bug triggered WARN_ON_ONCE() in disk_clear_events() reported in
bug#34662.

  https://bugzilla.kernel.org/show_bug.cgi?id=34662

Fix it by adding an outer mutex which protects both block count
manipulation and work cancellation.

-v2: Use outer mutex instead of bit waitqueue per Linus.

Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-06-09 20:43:59 +02:00
Tejun Heo c3af54afba block: remove non-syncing __disk_block_events() and fold it into disk_block_events()
After the previous update to disk_check_events(), nobody is using
non-syncing __disk_block_events().  Remove @sync and, as this makes
__disk_block_events() virtually identical to disk_block_events(),
remove the underscore prefixed version.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-06-09 20:43:55 +02:00
Tejun Heo a9dce2a3b4 block: don't use non-syncing event blocking in disk_check_events()
This patch is part of fix for triggering of WARN_ON_ONCE() in
disk_clear_events() reported in bug#34662.

  https://bugzilla.kernel.org/show_bug.cgi?id=34662

disk_clear_events() blocks events, schedules and flushes the event
work.  It expects the work to have started execution on schedule and
finished on return from flush.  WARN_ON_ONCE() triggers if the event
work hasn't executed as expected.  This problem happens because
__disk_block_events() fails to guarantee that the event work item is
not in flight on return from the function in race-free manner.  The
problem is two-fold and this patch addresses one of them.

When __disk_block_events() is called with @sync == %false, it bumps
event block count, calls cancel_delayed_work() and return.  This makes
it impossible to guarantee that event polling is not in flight on
return from syncing __disk_block_events() - if the first blocker was
non-syncing, polling could still be in progress and later syncing ones
would assume that the first blocker already canceled it.

Making __disk_block_events() cancel_sync regardless of block count
isn't feasible either as it may race with forced event checking in
disk_clear_events().

As disk_check_events() is the only user of non-syncing
__disk_block_events(), updating it to directly cancel and schedule
event work is the easiest way to solve the issue.

Note that there's another bug in __disk_block_events() and this patch
doesn't fix the issue completely.  Later patch will fix the other bug.

Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Meelis Roos <mroos@linux.ee>
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-06-09 20:43:54 +02:00
Tejun Heo 75e3f3ee3c block: always allocate genhd->ev if check_events is implemented
9fd097b149 (block: unexport DISK_EVENT_MEDIA_CHANGE for legacy/fringe
drivers) removed DISK_EVENT_MEDIA_CHANGE from legacy/fringe block
drivers which have inadequate ->check_events().  Combined with earlier
change 7c88a168da (block: don't propagate unlisted DISK_EVENTs to
userland), this enables using ->check_events() for internal processing
while avoiding enabling in-kernel block event polling which can lead
to infinite event loop.

Unfortunately, this made many drivers including floppy without any bit
set in disk->events and ->async_events in which case disk_add_events()
simply skipped allocation of disk->ev, which disables whole event
handling.  As ->check_events() is still used during open processing
for revalidation, this can lead to open failure.

This patch always allocates disk->ev if ->check_events is implemented.
In the long term, it would make sense to simply include the event
structure inline into genhd as it's now used by virtually all block
devices.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Ondrej Zary <linux@rainbow-software.org>
Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-05-26 21:06:50 +02:00
Tejun Heo 7c88a168da block: don't propagate unlisted DISK_EVENTs to userland
DISK_EVENT_MEDIA_CHANGE is used for both userland visible event and
internal event for revalidation of removeable devices.  Some legacy
drivers don't implement proper event detection and continuously
generate events under certain circumstances.  For example, ide-cd
generates media changed continuously if there's no media in the drive,
which can lead to infinite loop of events jumping back and forth
between the driver and userland event handler.

This patch updates disk event infrastructure such that it never
propagates events not listed in disk->events to userland.  Those
events are processed the same for internal purposes but uevent
generation is suppressed.

This also ensures that userland only gets events which are advertised
in the @events sysfs node lowering risk of confusion.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-21 19:43:58 +02:00
Lucas De Marchi 25985edced Fix common misspellings
Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-31 11:26:23 -03:00
Tejun Heo facc31ddc3 block: Don't implicitly trigger event check on disk_unblock_events()
Currently, disk_unblock_events() implicitly kick event check if the
block count reaches zero.  This behavior is not described in the
comment and hinders with future changes.  Make the unblocker
explicitly check events by calling disk_check_events() as necessary.

This patch doesn't cause any behavior difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
2011-03-09 19:54:27 +01:00
Tejun Heo e83a46bbb1 Merge branch 'for-linus' of ../linux-2.6-block into block-for-2.6.39/core
This merge creates two set of conflicts.  One is simple context
conflicts caused by removal of throtl_scheduled_delayed_work() in
for-linus and removal of throtl_shutdown_timer_wq() in
for-2.6.39/core.

The other is caused by commit 255bb490c8 (block: blk-flush shouldn't
call directly into q->request_fn() __blk_run_queue()) in for-linus
crashing with FLUSH reimplementation in for-2.6.39/core.  The conflict
isn't trivial but the resolution is straight-forward.

* __blk_run_queue() calls in flush_end_io() and flush_data_end_io()
  should be called with @force_kblockd set to %true.

* elv_insert() in blk_kick_flush() should use
  %ELEVATOR_INSERT_REQUEUE.

Both changes are to avoid invoking ->request_fn() directly from
request completion path and closely match the changes in the commit
255bb490c8.

Signed-off-by: Tejun Heo <tj@kernel.org>
2011-03-04 19:09:02 +01:00
Liu Yuan 53f22956ef block/genhd: Change some numerals into macros
Rename the numerals in the diskstats_show() into the macros.

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Liu Yuan <tailai.ly@taobao.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-02 11:00:15 -05:00
NeilBrown 93b270f76e Fix over-zealous flush_disk when changing device size.
There are two cases when we call flush_disk.
In one, the device has disappeared (check_disk_change) so any
data will hold becomes irrelevant.
In the oter, the device has changed size (check_disk_size_change)
so data we hold may be irrelevant.

In both cases it makes sense to discard any 'clean' buffers,
so they will be read back from the device if needed.

In the former case it makes sense to discard 'dirty' buffers
as there will never be anywhere safe to write the data.  In the
second case it *does*not* make sense to discard dirty buffers
as that will lead to file system corruption when you simply enlarge
the containing devices.

flush_disk calls __invalidate_devices.
__invalidate_device calls both invalidate_inodes and invalidate_bdev.

invalidate_inodes *does* discard I_DIRTY inodes and this does lead
to fs corruption.

invalidate_bev *does*not* discard dirty pages, but I don't really care
about that at present.

So this patch adds a flag to __invalidate_device (calling it
__invalidate_device2) to indicate whether dirty buffers should be
killed, and this is passed to invalidate_inodes which can choose to
skip dirty inodes.

flusk_disk then passes true from check_disk_change and false from
check_disk_size_change.

dm avoids tripping over this problem by calling i_size_write directly
rathher than using check_disk_size_change.

md does use check_disk_size_change and so is affected.

This regression was introduced by commit 608aeef17a which causes
check_disk_size_change to call flush_disk, so it is suitable for any
kernel since 2.6.27.

Cc: stable@kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NeilBrown <neilb@suse.de>
2011-02-24 17:25:47 +11:00
Jens Axboe 81c5e2ae33 Merge branch 'for-2.6.38/event-handling' into for-2.6.38/core 2011-01-13 14:47:54 +01:00
Jens Axboe 6c23a9681c block: add internal hd part table references
We can't use krefs since it's apparently restricted to very basic
reference counting.

This reverts commit e4a683c8.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-07 08:43:37 +01:00
Jerome Marchand 09e099d4ba block: fix accounting bug on cross partition merges
/proc/diskstats would display a strange output as follows.

$ cat /proc/diskstats |grep sda
   8       0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
   8       1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
                                                ~~~~~~~~~~
   8       2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
   8       3 sda3 54 487 2188 92 0 0 0 0 0 88 92
   8       4 sda4 4 0 8 0 0 0 0 0 0 0 0
   8       5 sda5 81 2027 2130 138 0 0 0 0 0 87 137

Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.

The detailed root cause is as follows.

Assuming that there are two partition, sda1 and sda2.

1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
   is 0 and sda2's one is 1.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

2. A bio belongs to sda1 is issued and is merged into the request mentioned on
   step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
   from sda2 region to sda1 region. However the two partition's
   hd_struct->in_flight are not changed.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

3. The request is finished and blk_account_io_done() is called. In this case,
   sda2's hd_struct->in_flight, not a sda1's one, is decremented.

        | hd_struct->in_flight
   ---------------------------
   sda1 |         -1
   sda2 |          1
   ---------------------------

The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.

Also add a refcount to struct hd_struct to keep the partition in
memory as long as users exist. We use kref_test_and_get() to ensure
we don't add a reference to a partition which is going away.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-01-05 16:57:38 +01:00
Yang Zhang e61eb2e93f fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
The major/minor device numbers are always defined and used as `unsigned'.

Signed-off-by: Yang Zhang <kthreadd@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-17 09:00:18 +01:00
Yang Zhang b9f985b6e0 block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
Signed-off-by: Yang Zhang <kthreadd@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-17 08:58:36 +01:00
Tejun Heo 77ea887e43 implement in-kernel gendisk events handling
Currently, media presence polling for removeable block devices is done
from userland.  There are several issues with this.

* Polling is done by periodically opening the device.  For SCSI
  devices, the command sequence generated by such action involves a
  few different commands including TEST_UNIT_READY.  This behavior,
  while perfectly legal, is different from Windows which only issues
  single command, GET_EVENT_STATUS_NOTIFICATION.  Unfortunately, some
  ATAPI devices lock up after being periodically queried such command
  sequences.

* There is no reliable and unintrusive way for a userland program to
  tell whether the target device is safe for media presence polling.
  For example, polling for media presence during an on-going burning
  session can make it fail.  The polling program can avoid this by
  opening the device with O_EXCL but then it risks making a valid
  exclusive user of the device fail w/ -EBUSY.

* Userland polling is unnecessarily heavy and in-kernel implementation
  is lighter and better coordinated (workqueue, timer slack).

This patch implements framework for in-kernel disk event handling,
which includes media presence polling.

* bdops->check_events() is added, which supercedes ->media_changed().
  It should check whether there's any pending event and return if so.
  Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and
  DISK_EVENT_EJECT_REQUEST.  ->check_events() is guaranteed not to be
  called parallelly.

* gendisk->events and ->async_events are added.  These should be
  initialized by block driver before passing the device to add_disk().
  The former contains the mask of all supported events and the latter
  the mask of all events which the device can report without polling.
  /sys/block/*/events[_async] export these to userland.

* Kernel parameter block.events_dfl_poll_msecs controls the system
  polling interval (default is 0 which means disable) and
  /sys/block/*/events_poll_msecs control polling intervals for
  individual devices (default is -1 meaning use system setting).  Note
  that if a device can report all supported events asynchronously and
  its polling interval isn't explicitly set, the device won't be
  polled regardless of the system polling interval.

* If a device is opened exclusively with write access, event checking
  is automatically disabled until all write exclusive accesses are
  released.

* There are event 'clearing' events.  For example, both of currently
  defined events are cleared after the device has been successfully
  opened.  This information is passed to ->check_events() callback
  using @clearing argument as a hint.

* Event checking is always performed from system_nrt_wq and timer
  slack is set to 25% for polling.

* Nothing changes for drivers which implement ->media_changed() but
  not ->check_events().  Going forward, all drivers will be converted
  to ->check_events() and ->media_change() will be dropped.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:38 +01:00
Tejun Heo d2bf1b6723 block: move register_disk() and del_gendisk() to block/genhd.c
There's no reason for register_disk() and del_gendisk() to be in
fs/partitions/check.c.  Move both to genhd.c.  While at it, collapse
unlink_gendisk(), which was artificially in a separate function due to
genhd.c / check.c split, into del_gendisk().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:38 +01:00
Tejun Heo dddd9dc340 block: kill genhd_media_change_notify()
There's no user of the facility.  Kill it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:38 +01:00
Jens Axboe f253b86b4a Revert "block: fix accounting bug on cross partition merges"
This reverts commit 7681bfeecc.

Conflicts:

	include/linux/genhd.h

It has numerous issues with the cleanup path and non-elevator
devices. Revert it for now so we can come up with a clean
version without rushing things.

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-10-24 22:06:02 +02:00
Linus Torvalds b9da057105 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (31 commits)
  driver core: Display error codes when class suspend fails
  Driver core: Add section count to memory_block struct
  Driver core: Add mutex for adding/removing memory blocks
  Driver core: Move find_memory_block routine
  hpilo: Despecificate driver from iLO generation
  driver core: Convert link_mem_sections to use find_memory_block_hinted.
  driver core: Introduce find_memory_block_hinted which utilizes kset_find_obj_hinted.
  kobject: Introduce kset_find_obj_hinted.
  driver core: fix build for CONFIG_BLOCK not enabled
  driver-core: base: change to new flag variable
  sysfs: only access bin file vm_ops with the active lock
  sysfs: Fail bin file mmap if vma close is implemented.
  FW_LOADER: fix kconfig dependency warning on HOTPLUG
  uio: Statically allocate uio_class and use class .dev_attrs.
  uio: Support 2^MINOR_BITS minors
  uio: Cleanup irq handling.
  uio: Don't clear driver data
  uio: Fix lack of locking in init_uio_class
  SYSFS: Allow boot time switching between deprecated and modern sysfs layout
  driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devices
  ...
2010-10-22 19:36:42 -07:00
Andi Kleen e52eec13cd SYSFS: Allow boot time switching between deprecated and modern sysfs layout
I have some systems which need legacy sysfs due to old tools that are
making assumptions that a directory can never be a symlink to another
directory, and it's a big hazzle to compile separate kernels for them.

This patch turns CONFIG_SYSFS_DEPRECATED into a run time option
that can be switched on/off the kernel command line. This way
the same binary can be used in both cases with just a option
on the command line.

The old CONFIG_SYSFS_DEPRECATED_V2 option is still there to set
the default. I kept the weird name to not break existing
config files.

Also the compat code can be still completely disabled by undefining
CONFIG_SYSFS_DEPRECATED_SWITCH -- just the optimizer takes
care of this now instead of lots of ifdefs. This makes the code
look nicer.

v2: This is an updated version on top of Kay's patch to only
handle the block devices. I tested it on my old systems
and that seems to work.

Cc: axboe@kernel.dk
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22 10:16:43 -07:00
Yasuaki Ishimatsu 7681bfeecc block: fix accounting bug on cross partition merges
/proc/diskstats would display a strange output as follows.

$ cat /proc/diskstats |grep sda
   8       0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
   8       1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
                                                ~~~~~~~~~~
   8       2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
   8       3 sda3 54 487 2188 92 0 0 0 0 0 88 92
   8       4 sda4 4 0 8 0 0 0 0 0 0 0 0
   8       5 sda5 81 2027 2130 138 0 0 0 0 0 87 137

Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.

The detailed root cause is as follows.

Assuming that there are two partition, sda1 and sda2.

1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
   is 0 and sda2's one is 1.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

2. A bio belongs to sda1 is issued and is merged into the request mentioned on
   step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
   from sda2 region to sda1 region. However the two partition's
   hd_struct->in_flight are not changed.

        | hd_struct->in_flight
   ---------------------------
   sda1 |          0
   sda2 |          1
   ---------------------------

3. The request is finished and blk_account_io_done() is called. In this case,
   sda2's hd_struct->in_flight, not a sda1's one, is decremented.

        | hd_struct->in_flight
   ---------------------------
   sda1 |         -1
   sda2 |          1
   ---------------------------

The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.

When reloading partition tables, quiesce IO to ensure that no
request references to the partition struct exists. When it is safe
to free the partition table, the IO for that device is restarted
again.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-10-19 09:07:02 +02:00
Signed-off-by: Jan Kara 01ea50638b block: Fix race during disk initialization
When a new disk is being discovered, add_disk() first ties the bdev to gendisk
(via register_disk()->blkdev_get()) and only after that calls
bdi_register_bdev(). Because register_disk() also creates disk's kobject, it
can happen that userspace manages to open and modify the device's data (or
inode) before its BDI is properly initialized leading to a warning in
__mark_inode_dirty().

Fix the problem by registering BDI early enough.

This patch addresses https://bugzilla.kernel.org/show_bug.cgi?id=16312

Cc: stable@kernel.org
Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-16 20:36:36 +02:00
Will Drewry b5af921ec0 init: add support for root devices specified by partition UUID
This is the third patch in a series which adds support for
storing partition metadata, optionally, off of the hd_struct.

One major use for that data is being able to resolve partition
by other identities than just the index on a block device.  Device
enumeration varies by platform and there's a benefit to being able
to use something like EFI GPT's GUIDs to determine the correct
block device and partition to mount as the root.

This change adds that support to root= by adding support for
the following syntax:

  root=PARTUUID=hex-uuid

Signed-off-by: Will Drewry <wad@chromium.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-09-15 16:14:03 +02:00