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  1. 16 Dec, 2010 7 commits
    • Tejun Heo's avatar
      sr: implement sr_check_events() · 93aae17a
      Tejun Heo authored 
      Replace sr_media_change() with sr_check_events().  It normally only
uses GET_EVENT_STATUS_NOTIFICATION to check both media change and
eject request.  If @clearing includes DISK_EVENT_MEDIA_CHANGE, it
issues TUR and compares whether media presence has changed.  The SCSI
specific media change uevent is kept for compatibility.

sr_media_change() was doing both media change check and revalidation.
The revalidation part is split into sr_block_revalidate_disk().
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      93aae17a
    • Tejun Heo's avatar
      scsi: replace sr_test_unit_ready() with scsi_test_unit_ready() · 9f8a2c23
      Tejun Heo authored 
      The usage of TUR has been confusing involving several different
commits updating different parts over time.  Currently, the only
differences between scsi_test_unit_ready() and sr_test_unit_ready()
are,

* scsi_test_unit_ready() also sets sdev->changed on NOT_READY.

* scsi_test_unit_ready() returns 0 if TUR ended with UNIT_ATTENTION or
  NOT_READY.

Due to the above two differences, sr is using its own
sr_test_unit_ready(), but sd - the sole user of the above extra
handling - doesn't even need them.

Where scsi_test_unit_ready() is used in sd_media_changed(), the code
is looking for device ready w/ media present state which is true iff
TUR succeeds w/o sense data or UA, and when the device is not ready
for whatever reason sd_media_changed() explicitly marks media as
missing so there's no reason to set sdev->changed automatically from
scsi_test_unit_ready() on NOT_READY.

Drop both special handlings from scsi_test_unit_ready(), which makes
it equivalant to sr_test_unit_ready(), and replace
sr_test_unit_ready() with scsi_test_unit_ready().  Also, drop the
unnecessary explicit NOT_READY check from sd_media_changed().
Checking return value is enough for testing device readiness.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      9f8a2c23
    • Tejun Heo's avatar
      scsi: fix TUR error handling in sr_media_change() · 638428ec
      Tejun Heo authored 
      sr_test_unit_ready() returns 0 iff TUR succeeded - IOW, when media is
present and the device is actually ready, so the return value wouldn't
be zero when TUR ends with sense data. sr_media_change() incorrectly
tests (retval || (scsi_sense_valid(sshdr)...)) when it tries to test
whether TUR failed without sense data or with sense data indicating
media-not-present.

Fix the test using scsi_status_is_good() and update comments.

- Fixed a comment typo spotted by Eike.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      638428ec
    • Tejun Heo's avatar
      cdrom: add ->check_events() support · 2d921729
      Tejun Heo authored 
      In principle, cdrom just needs to pass through ->check_events() but
CDROM_MEDIA_CHANGED ioctl makes things a bit more complex.  Just as
with ->media_changed() support, cdrom code needs to buffer the events
and serve them to ioctl and vfs as requested.

As the code has to deal with both ->check_events() and
->media_changed(), and vfs and ioctl event buffering, this patch adds
check_events caching on top of the existing cdi->mc_flags buffering.

It may be a good idea to deprecate CDROM_MEDIA_CHANGED ioctl and
remove all this mess.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      2d921729
    • Tejun Heo's avatar
      implement in-kernel gendisk events handling · 77ea887e
      Tejun Heo authored 
      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: default avatarTejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      77ea887e
    • Tejun Heo's avatar
      block: move register_disk() and del_gendisk() to block/genhd.c · d2bf1b67
      Tejun Heo authored 
      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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      d2bf1b67
    • Tejun Heo's avatar
      block: kill genhd_media_change_notify() · dddd9dc3
      Tejun Heo authored 
      There's no user of the facility.  Kill it.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      dddd9dc3
  3. 13 Dec, 2010 1 commit
  5. 30 Nov, 2010 2 commits
  7. 27 Nov, 2010 1 commit
  9. 16 Nov, 2010 4 commits
  11. 15 Nov, 2010 25 commits
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