Commit Graph

95 Commits

Author SHA1 Message Date
Jens Axboe 2d097c5021 sr: get/drop reference to device in revalidate and check_events
We can't just use scsi_cd() to get the scsi_cd structure, we have
to grab a live reference to the device. For both callbacks, we're
not inside an open where we already hold a reference to the device.

This fixes device removal/addition under concurrent device access,
which otherwise could result in the below oops.

NULL pointer dereference at 0000000000000010
PGD 0 P4D 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in:
sr 12:0:0:0: [sr2] scsi-1 drive
 scsi_debug crc_t10dif crct10dif_generic crct10dif_common nvme nvme_core sb_edac xl
sr 12:0:0:0: Attached scsi CD-ROM sr2
 sr_mod cdrom btrfs xor zstd_decompress zstd_compress xxhash lzo_compress zlib_defc
sr 12:0:0:0: Attached scsi generic sg7 type 5
 igb ahci libahci i2c_algo_bit libata dca [last unloaded: crc_t10dif]
CPU: 43 PID: 4629 Comm: systemd-udevd Not tainted 4.16.0+ #650
Hardware name: Dell Inc. PowerEdge T630/0NT78X, BIOS 2.3.4 11/09/2016
RIP: 0010:sr_block_revalidate_disk+0x23/0x190 [sr_mod]
RSP: 0018:ffff883ff357bb58 EFLAGS: 00010292
RAX: ffffffffa00b07d0 RBX: ffff883ff3058000 RCX: ffff883ff357bb66
RDX: 0000000000000003 RSI: 0000000000007530 RDI: ffff881fea631000
RBP: 0000000000000000 R08: ffff881fe4d38400 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000001b6 R12: 000000000800005d
R13: 000000000800005d R14: ffff883ffd9b3790 R15: 0000000000000000
FS:  00007f7dc8e6d8c0(0000) GS:ffff883fff340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000010 CR3: 0000003ffda98005 CR4: 00000000003606e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 ? __invalidate_device+0x48/0x60
 check_disk_change+0x4c/0x60
 sr_block_open+0x16/0xd0 [sr_mod]
 __blkdev_get+0xb9/0x450
 ? iget5_locked+0x1c0/0x1e0
 blkdev_get+0x11e/0x320
 ? bdget+0x11d/0x150
 ? _raw_spin_unlock+0xa/0x20
 ? bd_acquire+0xc0/0xc0
 do_dentry_open+0x1b0/0x320
 ? inode_permission+0x24/0xc0
 path_openat+0x4e6/0x1420
 ? cpumask_any_but+0x1f/0x40
 ? flush_tlb_mm_range+0xa0/0x120
 do_filp_open+0x8c/0xf0
 ? __seccomp_filter+0x28/0x230
 ? _raw_spin_unlock+0xa/0x20
 ? __handle_mm_fault+0x7d6/0x9b0
 ? list_lru_add+0xa8/0xc0
 ? _raw_spin_unlock+0xa/0x20
 ? __alloc_fd+0xaf/0x160
 ? do_sys_open+0x1a6/0x230
 do_sys_open+0x1a6/0x230
 do_syscall_64+0x5a/0x100
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-11 11:26:09 -06:00
Maurizio Lombardi 2bbea6e117 cdrom: do not call check_disk_change() inside cdrom_open()
when mounting an ISO filesystem sometimes (very rarely)
the system hangs because of a race condition between two tasks.

PID: 6766   TASK: ffff88007b2a6dd0  CPU: 0   COMMAND: "mount"
 #0 [ffff880078447ae0] __schedule at ffffffff8168d605
 #1 [ffff880078447b48] schedule_preempt_disabled at ffffffff8168ed49
 #2 [ffff880078447b58] __mutex_lock_slowpath at ffffffff8168c995
 #3 [ffff880078447bb8] mutex_lock at ffffffff8168bdef
 #4 [ffff880078447bd0] sr_block_ioctl at ffffffffa00b6818 [sr_mod]
 #5 [ffff880078447c10] blkdev_ioctl at ffffffff812fea50
 #6 [ffff880078447c70] ioctl_by_bdev at ffffffff8123a8b3
 #7 [ffff880078447c90] isofs_fill_super at ffffffffa04fb1e1 [isofs]
 #8 [ffff880078447da8] mount_bdev at ffffffff81202570
 #9 [ffff880078447e18] isofs_mount at ffffffffa04f9828 [isofs]
#10 [ffff880078447e28] mount_fs at ffffffff81202d09
#11 [ffff880078447e70] vfs_kern_mount at ffffffff8121ea8f
#12 [ffff880078447ea8] do_mount at ffffffff81220fee
#13 [ffff880078447f28] sys_mount at ffffffff812218d6
#14 [ffff880078447f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007fd9ea914e9a  RSP: 00007ffd5d9bf648  RFLAGS: 00010246
    RAX: 00000000000000a5  RBX: ffffffff81698c49  RCX: 0000000000000010
    RDX: 00007fd9ec2bc210  RSI: 00007fd9ec2bc290  RDI: 00007fd9ec2bcf30
    RBP: 0000000000000000   R8: 0000000000000000   R9: 0000000000000010
    R10: 00000000c0ed0001  R11: 0000000000000206  R12: 00007fd9ec2bc040
    R13: 00007fd9eb6b2380  R14: 00007fd9ec2bc210  R15: 00007fd9ec2bcf30
    ORIG_RAX: 00000000000000a5  CS: 0033  SS: 002b

This task was trying to mount the cdrom.  It allocated and configured a
super_block struct and owned the write-lock for the super_block->s_umount
rwsem. While exclusively owning the s_umount lock, it called
sr_block_ioctl and waited to acquire the global sr_mutex lock.

PID: 6785   TASK: ffff880078720fb0  CPU: 0   COMMAND: "systemd-udevd"
 #0 [ffff880078417898] __schedule at ffffffff8168d605
 #1 [ffff880078417900] schedule at ffffffff8168dc59
 #2 [ffff880078417910] rwsem_down_read_failed at ffffffff8168f605
 #3 [ffff880078417980] call_rwsem_down_read_failed at ffffffff81328838
 #4 [ffff8800784179d0] down_read at ffffffff8168cde0
 #5 [ffff8800784179e8] get_super at ffffffff81201cc7
 #6 [ffff880078417a10] __invalidate_device at ffffffff8123a8de
 #7 [ffff880078417a40] flush_disk at ffffffff8123a94b
 #8 [ffff880078417a88] check_disk_change at ffffffff8123ab50
 #9 [ffff880078417ab0] cdrom_open at ffffffffa00a29e1 [cdrom]
#10 [ffff880078417b68] sr_block_open at ffffffffa00b6f9b [sr_mod]
#11 [ffff880078417b98] __blkdev_get at ffffffff8123ba86
#12 [ffff880078417bf0] blkdev_get at ffffffff8123bd65
#13 [ffff880078417c78] blkdev_open at ffffffff8123bf9b
#14 [ffff880078417c90] do_dentry_open at ffffffff811fc7f7
#15 [ffff880078417cd8] vfs_open at ffffffff811fc9cf
#16 [ffff880078417d00] do_last at ffffffff8120d53d
#17 [ffff880078417db0] path_openat at ffffffff8120e6b2
#18 [ffff880078417e48] do_filp_open at ffffffff8121082b
#19 [ffff880078417f18] do_sys_open at ffffffff811fdd33
#20 [ffff880078417f70] sys_open at ffffffff811fde4e
#21 [ffff880078417f80] system_call_fastpath at ffffffff81698c49
    RIP: 00007f29438b0c20  RSP: 00007ffc76624b78  RFLAGS: 00010246
    RAX: 0000000000000002  RBX: ffffffff81698c49  RCX: 0000000000000000
    RDX: 00007f2944a5fa70  RSI: 00000000000a0800  RDI: 00007f2944a5fa70
    RBP: 00007f2944a5f540   R8: 0000000000000000   R9: 0000000000000020
    R10: 00007f2943614c40  R11: 0000000000000246  R12: ffffffff811fde4e
    R13: ffff880078417f78  R14: 000000000000000c  R15: 00007f2944a4b010
    ORIG_RAX: 0000000000000002  CS: 0033  SS: 002b

This task tried to open the cdrom device, the sr_block_open function
acquired the global sr_mutex lock. The call to check_disk_change()
then saw an event flag indicating a possible media change and tried
to flush any cached data for the device.
As part of the flush, it tried to acquire the super_block->s_umount
lock associated with the cdrom device.
This was the same super_block as created and locked by the previous task.

The first task acquires the s_umount lock and then the sr_mutex_lock;
the second task acquires the sr_mutex_lock and then the s_umount lock.

This patch fixes the issue by moving check_disk_change() out of
cdrom_open() and let the caller take care of it.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-09 08:06:35 -07:00
Bart Van Assche 0624cbb1e2 scsi: sd: sr: Convert two assignments into warning statements
Before scsi_prep_fn() calls the ULP .init_command() callback
function it stores the SCSI command pointer in request.special.
This means that the SCpnt = rq->special assignments in the sd
and sr drivers assign a pointer to itself. Hence convert these
two assignment statements into warning statements.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-08-25 17:08:08 -04:00
Martin K. Petersen a00a786251 scsi: sr: Sanity check returned mode data
Kefeng Wang discovered that old versions of the QEMU CD driver would
return mangled mode data causing us to walk off the end of the buffer in
an attempt to parse it. Sanity check the returned mode sense data.

Cc: <stable@vger.kernel.org>
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-04-07 17:07:14 -04:00
Jens Axboe 818551e2b2 Merge branch 'for-4.11/next' into for-4.11/linus-merge
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-17 14:08:19 -07:00
Kees Cook 853fe1bf75 cdrom: Make device operations read-only
Since function tables are a common target for attackers, it's best to keep
them in read-only memory. As such, this makes the CDROM device ops tables
const. This drops additionally n_minors, since it isn't used meaningfully,
and sets the only user of cdrom_dummy_generic_packet explicitly so the
variables can all be const.

Inspired by similar changes in grsecurity/PaX.

Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-14 08:29:56 -07:00
Christoph Hellwig aebf526b53 block: fold cmd_type into the REQ_OP_ space
Instead of keeping two levels of indirection for requests types, fold it
all into the operations.  The little caveat here is that previously
cmd_type only applied to struct request, while the request and bio op
fields were set to plain REQ_OP_READ/WRITE even for passthrough
operations.

Instead this patch adds new REQ_OP_* for SCSI passthrough and driver
private requests, althought it has to add two for each so that we
can communicate the data in/out nature of the request.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-31 14:00:44 -07:00
Linus Torvalds 7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Julia Lawall a816b4c67a scsi: sr: constify sr_pm_ops structure
sr_pm_ops, of type struct dev_pm_ops, is never modified, so declare it
as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-09-04 01:28:08 -04:00
Dan Williams 0d52c756a6 block: convert to device_add_disk()
For block drivers that specify a parent device, convert them to use
device_add_disk().

This conversion was done with the following semantic patch:

    @@
    struct gendisk *disk;
    expression E;
    @@

    - disk->driverfs_dev = E;
    ...
    - add_disk(disk);
    + device_add_disk(E, disk);

    @@
    struct gendisk *disk;
    expression E1, E2;
    @@

    - disk->driverfs_dev = E1;
    ...
    E2 = disk;
    ...
    - add_disk(E2);
    + device_add_disk(E1, E2);

...plus some manual fixups for a few missed conversions.

Cc: Jens Axboe <axboe@fb.com>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@hansenpartnership.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2016-06-27 12:26:08 -07:00
Alan Stern 13b4389143 SCSI: fix crashes in sd and sr runtime PM
Runtime suspend during driver probe and removal can cause problems.
The driver's runtime_suspend or runtime_resume callbacks may invoked
before the driver has finished binding to the device or after the
driver has unbound from the device.

This problem shows up with the sd and sr drivers, and can cause disk
or CD/DVD drives to become unusable as a result.  The fix is simple.
The drivers store a pointer to the scsi_disk or scsi_cd structure as
their private device data when probing is finished, so we simply have
to be sure to clear the private data during removal and test it during
runtime suspend/resume.

This fixes <https://bugs.debian.org/801925>.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Paul Menzel <paul.menzel@giantmonkey.de>
Reported-by: Erich Schubert <erich@debian.org>
Reported-by: Alexandre Rossi <alexandre.rossi@gmail.com>
Tested-by: Paul Menzel <paul.menzel@giantmonkey.de>
Tested-by: Erich Schubert <erich@debian.org>
CC: <stable@vger.kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2016-01-26 17:24:16 -08:00
Christoph Hellwig 3af6b35261 scsi: remove scsi_driver owner field
The driver core driver structure has grown an owner field and now
requires it to be set for all modular drivers.  Set it up for
all scsi_driver instances and get rid of the now superflous
scsi_driver owner field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Shane M Seymour <shane.seymour@hp.com>
Reviewed-by: Ewan D. Milne <emilne@redhat.com
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24 20:01:28 +01:00
Christoph Hellwig 3c356bde19 scsi: stop passing a gfp_mask argument down the command setup path
There is no reason for ULDs to pass in a flag on how to allocate the S/G
lists.  While we don't need GFP_ATOMIC for the blk-mq case because we
don't hold locks, that decision can be made way down the chain without
having to pass a pointless gfp_mask argument.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-24 19:56:55 +01:00
Christoph Hellwig 906d15fbd2 scsi: split scsi_nonblockable_ioctl
The calling conventions for this function are bad as it could return
-ENODEV both for a device not currently online and a not recognized ioctl.

Add a new scsi_ioctl_block_when_processing_errors function that wraps
scsi_block_when_processing_errors with the a special case for the
SG_SCSI_RESET ioctl command, and handle the SG_SCSI_RESET case itself
in scsi_ioctl.  All callers of scsi_ioctl now must call the above helper
to check for the EH state, so that the ioctl handler itself doesn't
have to.

Reported-by: Robert Elliott <Elliott@hp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-12 11:16:11 +01:00
Subhash Jadavani 6fe8c1dbef scsi: balance out autopm get/put calls in scsi_sysfs_add_sdev()
SCSI Well-known logical units generally don't have any scsi driver
associated with it which means no one will call scsi_autopm_put_device()
on these wlun scsi devices and this would result in keeping the
corresponding scsi device always active (hence LLD can't be suspended as
well). Same exact problem can be seen for other scsi device representing
normal logical unit whose driver is yet to be loaded. This patch fixes
the above problem with this approach:

- make the scsi_autopm_put_device call at the end of scsi_sysfs_add_sdev
  to make it balance out the get earlier in the function.
- let drivers do paired get/put calls in their probe methods.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-09-15 16:02:05 -07:00
Christoph Hellwig fd2eb9034e scsi: move the writeable field from struct scsi_device to struct scsi_cd
We currently set the field in common code based on the device type,
but then only use it in the cdrom driver which also overrides the
value previously set in the generic code.

Just leave this entirely to the CDROM driver to make everyones life
simpler.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
2014-07-25 17:16:41 -04:00
Christoph Hellwig 5158a899d8 scsi: set sc_data_direction in common code
The data direction fiel in the SCSI command is derived only from the block
request structure.  Move setting it up into common code instead of
duplicating it in the ULDs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-07-17 22:11:41 +02:00
Christoph Hellwig 3868cf8ea7 scsi: restructure command initialization for TYPE_FS requests
We should call the device handler prep_fn for all TYPE_FS requests,
not just simple read/write calls that are handled by the disk driver.

Restructure the common I/O code to call the prep_fn handler and zero
out the CDB, and just leave the call to scsi_init_io to the ULDs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-07-17 22:11:27 +02:00
Hannes Reinecke 96eefad2d9 scsi: Implement sr_printk()
Update the sr driver to use dev_printk() variants instead of
plain printk(); this will prefix logging messages with the
appropriate device.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-07-17 22:07:39 +02:00
Christoph Hellwig a1b73fc194 scsi: reintroduce scsi_driver.init_command
Instead of letting the ULD play games with the prep_fn move back to
the model of a central prep_fn with a callback to the ULD.  This
already cleans up and shortens the code by itself, and will be required
to properly support blk-mq in the SCSI midlayer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Reviewed-by: Mike Christie <michaelc@cs.wisc.edu>
Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-05-19 12:35:09 +02:00
Aaron Lu 6627b38fd9 [SCSI] sr: use block layer runtime PM
Migrate sr to make use of block layer runtime PM. Accordingly, the
SCSI bus layer runtime PM callback is simplified as all SCSI drivers
implementing runtime PM now use the block layer's request-based
mechanism.

Note that due to the device will be polled by kernel at a constant
interval, if the autosuspend delay is set longer than the polling
interval then the device will never suspend.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-12-16 10:57:51 -08:00
Al Viro db2a144bed block_device_operations->release() should return void
The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-05-07 02:16:21 -04:00
Aaron Lu 6f4c827e68 [libata] scsi: no poll when ODD is powered off
When the ODD is powered off, any action the user did to the ODD that
would generate a media event will trigger an ACPI interrupt, so the
poll for media event is no longer necessary. And the poll will also
cause a runtime status change, which will stop the ODD from staying in
powered off state, so the poll should better be stopped.

But since we don't have access to the gendisk structure in LLDs, here
comes the disk_events_disable_depth for scsi device. This field is a
hint set by LLDs to convey information to upper layer drivers. A value
of 0 means media poll is necessary for the device, while values above 0
means media poll is not needed and should better be skipped. So we can
increase its value when we are to power off the ODD in ATA layer and
decrease its value when the ODD is powered on, effectively silence the
media events poll.

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2013-01-25 15:36:43 -05:00
Aaron Lu 6c7f1e2f12 [SCSI] sr: support runtime pm
This patch adds runtime pm support for sr.

It did this by increasing the runtime usage_count of the device when
its block device is accessed. And decreasing the runtime usage_count
of the device when the access is done.

If there is media inside, runtime suspend is not allowed as we don't
always know if the ODD is being used or not.

The idea is discussed here:
http://thread.gmane.org/gmane.linux.acpi.devel/55243/focus=52703
and the restriction to check media inside is discussed here:
http://thread.gmane.org/gmane.linux.ide/53665/focus=58836

Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
2013-01-25 15:36:38 -05:00
Kay Sievers 79b9677d88 [SCSI] sr: check_events() ignore GET_EVENT when TUR says otherwise
Some broken devices indicates that media has changed on every
GET_EVENT_STATUS_NOTIFICATION.  This translates into MEDIA_CHANGE
uevent on every open() which lets udev run into a loop.

Verify GET_EVENT result against TUR and if it generates spurious
events for several times in a row, ignore the GET_EVENT events, and
trust only the TUR status.

This is the log of a USB stick with a (broken) fake CDROM drive:

 scsi 5:0:0:0: Direct-Access     SanDisk  U3 Cruzer Micro  8.02 PQ: 0 ANSI: 0 CCS
 sd 5:0:0:0: Attached scsi generic sg3 type 0
 scsi 5:0:0:1: CD-ROM            SanDisk  U3 Cruzer Micro  8.02 PQ: 0 ANSI: 0
 sd 5:0:0:0: [sdb] Attached SCSI removable disk
 sr2: scsi3-mmc drive: 48x/48x tray
 sr 5:0:0:1: Attached scsi CD-ROM sr2
 sr 5:0:0:1: Attached scsi generic sg4 type 5
 sr2: GET_EVENT and TUR disagree continuously, suppress GET_EVENT events
 sd 5:0:0:0: [sdb] 31777279 512-byte logical blocks: (16.2 GB/15.1 GiB)
 sd 5:0:0:0: [sdb] No Caching mode page present
 sd 5:0:0:0: [sdb] Assuming drive cache: write through
 sd 5:0:0:0: [sdb] No Caching mode page present
 sd 5:0:0:0: [sdb] Assuming drive cache: write through
 sdb: sdb1

-tj: Updated to consider only spurious GET_EVENT events among
     different types of disagreement and allow using TUR for kernel
     event polling after GET_EVENT is ignored.

Reported-By: Markus Rathgeb maggu2810@googlemail.com
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org	# >= v2.6.38, fixes udev busy looping w/ certain devices
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2011-07-21 14:15:58 -07:00
Tejun Heo d4dc210f69 block: don't block events on excl write for non-optical devices
Disk event code automatically blocks events on excl write.  This is
primarily to avoid issuing polling commands while burning is in
progress.  This behavior doesn't fit other types of devices with
removeable media where polling commands don't have adverse side
effects and door locking usually doesn't exist.

This patch introduces new genhd flag which controls the auto-blocking
behavior and uses it to enable auto-blocking only on optical devices.

Note for stable: 2.6.38 and later only

Cc: stable@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-04-21 20:54:46 +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 f4013c3879 [SCSI] sd,sr: kill compat SDEV_MEDIA_CHANGE event
SDEV_MEDIA_CHANGE event was first added by commit a341cd0f (SCSI: add
asynchronous event notification API) for SATA AN support and then
extended to cover generic media change events by commit 285e9670
([SCSI] sr,sd: send media state change modification events).

This event was mapped to block device in userland with all properties
stripped to simulate CHANGE event on the block device, which, in turn,
was used to trigger further userspace action on media change.

The recent addition of disk event framework kept this event for
backward compatibility but it turns out to be unnecessary and causes
erratic and inefficient behavior.  The new disk event generates proper
events on the block devices and the compat events are mapped to block
device with all properties stripped, so the block device ends up
generating multiple duplicate events for single actual event.

This patch removes the compat event generation from both sr and sd as
suggested by Kay Sievers.  Both existing and newer versions of udev
and the associated tools will behave better with the removal of these
events as they from the beginning were expecting events on the block
devices.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-01-14 09:17:35 -06:00
Tejun Heo 93aae17af1 sr: implement sr_check_events()
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: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:39 +01:00
Tejun Heo 9f8a2c23c6 scsi: replace sr_test_unit_ready() with scsi_test_unit_ready()
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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:39 +01:00
Tejun Heo 638428ece6 scsi: fix TUR error handling in sr_media_change()
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: Tejun Heo <tj@kernel.org>
Cc: Rolf Eike Beer <eike-kernel@sf-tec.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-12-16 17:53:39 +01:00
Linus Torvalds 5cc1035062 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (141 commits)
  USB: mct_u232: fix broken close
  USB: gadget: amd5536udc.c: fix error path
  USB: imx21-hcd - fix off by one resource size calculation
  usb: gadget: fix Kconfig warning
  usb: r8a66597-udc: Add processing when USB was removed.
  mxc_udc: add workaround for ENGcm09152 for i.MX35
  USB: ftdi_sio: add device ids for ScienceScope
  USB: musb: AM35x: Workaround for fifo read issue
  USB: musb: add musb support for AM35x
  USB: AM35x: Add musb support
  usb: Fix linker errors with CONFIG_PM=n
  USB: ohci-sh - use resource_size instead of defining its own resource_len macro
  USB: isp1362-hcd - use resource_size instead of defining its own resource_len macro
  USB: isp116x-hcd - use resource_size instead of defining its own resource_len macro
  USB: xhci: Fix compile error when CONFIG_PM=n
  USB: accept some invalid ep0-maxpacket values
  USB: xHCI: PCI power management implementation
  USB: xHCI: bus power management implementation
  USB: xHCI: port remote wakeup implementation
  USB: xHCI: port power management implementation
  ...

Manually fix up (non-data) conflict: the SCSI merge gad renamed the
'hw_sector_size' member to 'physical_block_size', and the USB tree
brought a new use of it.
2010-10-22 20:30:48 -07:00
Hans de Goede 8e04d8056c scsi/sr: add no_read_disc_info scsi_device flag
Some USB devices emulate a usb-mass-storage attached (scsi) cdrom device,
usually this fake cdrom contains the windows software for the device.
While working on supporting Appotech ax3003 based photoframes, which do
this I discovered that they will go of into lala land when ever they see a
READ_DISC_INFO scsi command.

Thus this patch adds a scsi_device flag (which can then be set by the
usb-storage driver through an unsual-devs entry), to indicate this, and
makes the sr driver honor this flag.

I know this sucks, but as discussed on linux-scsi list there is no other
way to make this device work properly.

Looking at usb traces made under windows, windows never sends a
READ_DISC_INFO during normal interactions with a usb cdrom device.  So as
this cdrom emulation thingie becomes more common we might see more of this
problem.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-10-22 10:22:04 -07:00
Arnd Bergmann 2a48fc0ab2 block: autoconvert trivial BKL users to private mutex
The block device drivers have all gained new lock_kernel
calls from a recent pushdown, and some of the drivers
were already using the BKL before.

This turns the BKL into a set of per-driver mutexes.
Still need to check whether this is safe to do.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2010-10-05 15:01:10 +02:00
Arnd Bergmann 6e9624b8ca block: push down BKL into .open and .release
The open and release block_device_operations are currently
called with the BKL held. In order to change that, we must
first make sure that all drivers that currently rely
on this have no regressions.

This blindly pushes the BKL into all .open and .release
operations for all block drivers to prepare for the
next step. The drivers can subsequently replace the BKL
with their own locks or remove it completely when it can
be shown that it is not needed.

The functions blkdev_get and blkdev_put are the only
remaining users of the big kernel lock in the block
layer, besides a few uses in the ioctl code, none
of which need to serialize with blkdev_{get,put}.

Most of these two functions is also under the protection
of bdev->bd_mutex, including the actual calls to
->open and ->release, and the common code does not
access any global data structures that need the BKL.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-07 18:25:34 +02:00
Arnd Bergmann 8a6cfeb6de block: push down BKL into .locked_ioctl
As a preparation for the removal of the big kernel
lock in the block layer, this removes the BKL
from the common ioctl handling code, moving it
into every single driver still using it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-07 18:25:00 +02:00
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00
Tejun Heo 5915136d4d [SCSI] sr: consider the last written sector when determining media size
On certain cases, UDF disc doesn't report capacity correctly via
READ_CAPACITY but TOC or trackinfo contains valid information which
can be obtained using cdrom_get_last_written().  ide-cd considers both
values and uses the larger one.  Do the same in sr.  This fixes
bko#9668.

 http://bugzilla.kernel.org/show_bug.cgi?id=9668

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Milan Kocian <milan.kocian@wq.cz>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2009-10-02 09:45:46 -05:00
Alexey Dobriyan 83d5cde47d const: make block_device_operations const
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-22 07:17:25 -07:00
Hannes Reinecke b391277a56 sd, sr: fix Driver 'sd' needs updating message
If a SCSI ULD driver sets blk_queue_prep_rq(), it should clean it
up itself on remove(), and not from the bus callbacks. This
removes the need to hook into bus->remove(), which should not
be used at the same time as driver->remove().

[jejb: fix sdkp initialisation problem due to mismerge]
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-06-21 12:01:27 -05:00
Martin K. Petersen e1defc4ff0 block: Do away with the notion of hardsect_size
Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case.  The
sector size will be 4KB but the logical block size will remain
512-bytes.  Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Tejun Heo 83096ebf12 block: convert to pos and nr_sectors accessors
With recent cleanups, there is no place where low level driver
directly manipulates request fields.  This means that the 'hard'
request fields always equal the !hard fields.  Convert all
rq->sectors, nr_sectors and current_nr_sectors references to
accessors.

While at it, drop superflous blk_rq_pos() < 0 test in swim.c.

[ Impact: use pos and nr_sectors accessors ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: Mike Miller <mike.miller@hp.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: unsik Kim <donari75@gmail.com>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:54 +02:00
James Bottomley a9bddd7463 [SCSI] fix recovered error handling
We have a problem with recovered error handling in that any command
which goes down as BLOCK_PC but which returns a sense code of RECOVERED
ERROR gets completed with -EIO.  For actual SG_IO commands, this doesn't
matter at all, since the error return code gets dropped in favour of
req->errors which contain the SCSI completion code.

However, if this command is part of the block system, then it will pay
attention to the returned error code.  In particularly if a SYNCHRONIZE
CACHE from a barrier command completes with RECOVERED ERROR, the
resulting -EIO on the barrier causes block to error the request and
return it to the filesystem.  Fix this by converting the -EIO for
recovered error to zero, plus remove the printing of this from sd and sr
so the message isn't double printed.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-04-03 09:22:55 -05:00
FUJITA Tomonori f4f4e47e4a [SCSI] add residual argument to scsi_execute and scsi_execute_req
scsi_execute() and scsi_execute_req() discard the residual length
information. Some callers need it. This adds residual argument
(optional) to scsi_execute and scsi_execute_req.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2008-12-29 11:24:24 -06:00
Christoph Hellwig fd4ce1acd0 [PATCH 1/2] kill FMODE_NDELAY_NOW
Update FMODE_NDELAY before each ioctl call so that we can kill the
magic FMODE_NDELAY_NOW.  It would be even better to do this directly
in setfl(), but for that we'd need to have FMODE_NDELAY for all files,
not just block special files.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-12-04 04:22:57 -05:00
Al Viro 40cc51be69 [PATCH] switch sr
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-21 07:48:50 -04:00
Al Viro d4430d62fa [PATCH] beginning of methods conversion
To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
	1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both.  That's this changeset.
	2) for each driver convert to new methods.  *ALL* drivers
are converted in this series.
	3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain.  The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
	open(bdev, mode)
	release(disk, mode)
	ioctl(bdev, mode, cmd, arg)		/* Called without BKL */
	compat_ioctl(bdev, mode, cmd, arg)
	locked_ioctl(bdev, mode, cmd, arg)	/* Called with BKL, legacy */

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-21 07:47:32 -04:00
Al Viro 83ff6fe858 [PATCH] don't mess with file in scsi_nonblockable_ioctl()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-21 07:47:28 -04:00
Al Viro bbc1cc9784 [PATCH] switch cdrom_{open,release,ioctl} to sane APIs
... convert to it in callers

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-10-21 07:47:22 -04:00
Jens Axboe 242f9dcb8b block: unify request timeout handling
Right now SCSI and others do their own command timeout handling.
Move those bits to the block layer.

Instead of having a timer per command, we try to be a bit more clever
and simply have one per-queue. This avoids the overhead of having to
tear down and setup a timer for each command, so it will result in a lot
less timer fiddling.

Signed-off-by: Mike Anderson <andmike@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:13 +02:00