async_schedule() sd resume work to allow disks and other devices to
resume in parallel.

This moves the entirety of scsi_device resume to an async context to
ensure that scsi_device_resume() remains ordered with respect to the
completion of the start/stop command.  For the duration of the resume,
new command submissions (that do not originate from the scsi-core) will
be deferred (BLKPREP_DEFER).

It adds a new ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain) as a container
of these operations.  Like scsi_sd_probe_domain it is flushed at
sd_remove() time to ensure async ops do not continue past the
end-of-life of the sdev.  The implementation explicitly refrains from
reusing scsi_sd_probe_domain directly for this purpose as it is flushed
at the end of dpm_resume(), potentially defeating some of the benefit.
Given sdevs are quiesced it is permissible for these resume operations
to bleed past the async_synchronize_full() calls made by the driver
core.

We defer the resolution of which pm callback to call until
scsi_dev_type_{suspend|resume} time and guarantee that the callback
parameter is never NULL.  With this in place the type of resume
operation is encoded in the async function identifier.

There is a concern that async resume could trigger PSU overload.  In the
enterprise, storage enclosures enforce staggered spin-up regardless of
what the kernel does making async scanning safe by default.  Outside of
that context a user can disable asynchronous scanning via a kernel
command line or CONFIG_SCSI_SCAN_ASYNC.  Honor that setting when
deciding whether to do resume asynchronously.

Inspired by Todd's analysis and initial proposal [2]:
https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach

Cc: Len Brown <len.brown@intel.com>
Cc: Phillip Susi <psusi@ubuntu.com>
[alan: bug fix and clean up suggestion]
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Suggested-by: NTodd Brandt <todd.e.brandt@linux.intel.com>
[djbw: kick all resume work to the async queue]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

EVPD page 0x83 is used to uniquely identify the device.
So instead of having each and every program issue a separate
SG_IO call to retrieve this information it does make far more
sense to display it in sysfs.

Some older devices (most notably tapes) will only report reliable
information in page 0x80 (Unit Serial Number). So export this
in the sysfs attribute 'vpd_pg80'.

[jejb: checkpatch fix]
[hare: attach after transport configure]
[fengguang.wu@intel.com: spotted problems with the original now fixed]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In the highly unusual case where two threads are running concurrently through
the scanning code scanning the same target, we run into the situation where
one may allocate the target while the other is still using it.  In this case,
because the reap checks for STARGET_CREATED and kills the target without
reference counting, the second thread will do the wrong thing on reap.

Fix this by reference counting even creates and doing the STARGET_CREATED
check in the final put.
Tested-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org # delay backport for 2 months for field testing
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patch eliminates the reap_ref and replaces it with a proper kref.
On last put of this kref, the target is removed from visibility in
sysfs.  The final call to scsi_target_reap() for the device is done from
__scsi_remove_device() and only if the device was made visible.  This
ensures that the target disappears as soon as the last device is gone
rather than waiting until final release of the device (which is often
too long).
Reviewed-by: NAlan Stern <stern@rowland.harvard.edu>
Tested-by: NSarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org # delay backport by 2 months for field testing
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Not all disks fill out the VPD pages correctly. Add a blacklist flag
that allows us ignore the SBC-3 VPD pages for a given device. The
BLIST_SKIP_VPD_PAGES flag triggers our existing skip_vpd_pages
scsi_device parameter to bypass VPD scanning.

Also blacklist the offending Seagate drive model.
Reported-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Introduce eh_timeout which can be used for error handling purposes. This
was previously hardcoded to 10 seconds in the SCSI error handling
code. However, for some fast-fail scenarios it is necessary to be able
to tune this as it can take several iterations (bus device, target, bus,
controller) before we give up.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Hitachi Ultrastar 15K300 is quirky. Disable T10 PI (DIF).
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This is a particularly nasty SCSI ATA Translation Layer (SATL) problem.

SAT-2 says (section 8.12.2)

        if the device is in the stopped state as the result of
        processing a START STOP UNIT command (see 9.11), then the SATL
        shall terminate the TEST UNIT READY command with CHECK CONDITION
        status with the sense key set to NOT READY and the additional
        sense code of LOGICAL UNIT NOT READY, INITIALIZING COMMAND
        REQUIRED;

mpt2sas internal SATL seems to implement this.  The result is very confusing
standby behaviour (using hdparm -y).  If you suspend a drive and then send
another command, usually it wakes up.  However, if the next command is a TEST
UNIT READY, the SATL sees that the drive is suspended and proceeds to follow
the SATL rules for this, returning NOT READY to all subsequent commands.  This
means that the ordering of TEST UNIT READY is crucial: if you send TUR and
then a command, you get a NOT READY to both back.  If you send a command and
then a TUR, you get GOOD status because the preceeding command woke the drive.

This bit us badly because

commit 85ef06d1
Author: Tejun Heo <tj@kernel.org>
Date:   Fri Jul 1 16:17:47 2011 +0200

    block: flush MEDIA_CHANGE from drivers on close(2)

Changed our ordering on TEST UNIT READY commands meaning that SATA drives
connected to an mpt2sas now suspend and refuse to wake (because the mpt2sas
SATL sees the suspend *before* the drives get awoken by the next ATA command)
resulting in lots of failed commands.

The standard is completely nuts forcing this inconsistent behaviour, but we
have to work around it.

The fix for this is twofold:

   1. Set the allow_restart flag so we wake the drive when we see it has been
      suspended

   2. Return all TEST UNIT READY status directly to the mid layer without any
      further error handling which prevents us causing error handling which
      may offline the device just because of a media check TUR.
Reported-by: NMatthias Prager <linux@matthiasprager.de>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This reverts commit 43a8d39d.

Commit 43a8d39d fixed the fact that wait_for_device_probe() was unable
to flush sd probe work.  Now that sd probe work is once again flushable
via wait_for_device_probe() this workaround is no longer needed.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Tested-by: NEldad Zack <eldad@fogrefinery.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Now that scsi registers its async scan work with the async subsystem,
wait_for_device_probe() is sufficient for ensuring all scanning is
complete.

[jejb: fix merge problems with eea03c20 Make wait_for_device_probe() also do scsi_complete_async_scans()]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Tested-by: NEldad Zack <eldad@fogrefinery.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This is preparation to enable async_synchronize_full() to be used as a
replacement for scsi_complete_async_scans(), i.e. to stop leaking scsi
internal details where they are not needed.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Tested-by: NEldad Zack <eldad@fogrefinery.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The following crash results from cases where the end_device has been
removed before scsi_sysfs_add_sdev has had a chance to run.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
 IP: [<ffffffff8115e100>] sysfs_create_dir+0x32/0xb6
 ...
 Call Trace:
  [<ffffffff8125e4a8>] kobject_add_internal+0x120/0x1e3
  [<ffffffff81075149>] ? trace_hardirqs_on+0xd/0xf
  [<ffffffff8125e641>] kobject_add_varg+0x41/0x50
  [<ffffffff8125e70b>] kobject_add+0x64/0x66
  [<ffffffff8131122b>] device_add+0x12d/0x63a
  [<ffffffff814b65ea>] ? _raw_spin_unlock_irqrestore+0x47/0x56
  [<ffffffff8107de15>] ? module_refcount+0x89/0xa0
  [<ffffffff8132f348>] scsi_sysfs_add_sdev+0x4e/0x28a
  [<ffffffff8132dcbb>] do_scan_async+0x9c/0x145

...teach scsi_sysfs_add_devices() to check for deleted devices() before
trying to add them, and teach scsi_remove_target() how to remove targets
that have not been added via device_add().

Cc: <stable@vger.kernel.org>
Reported-by: NDariusz Majchrzak <dariusz.majchrzak@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Commit a7a20d10 "[SCSI] sd: limit the scope of the async probe domain"
moved sd probe work out of reach of wait_for_device_probe().  Allow it
to be synced via scsi_complete_async_scans().
Reported-by: NMeelis Roos <mroos@linux.ee>
Tested-by: NMeelis Roos <mroos@linux.ee>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In do_scan_async(), calling scsi_autopm_put_host(shost) may reference
freed shost, and cause Posison overwitten warning.
Yes, this case can happen, for example, an USB is disconnected just
when do_scan_async() thread starts to run, then scsi_host_put() called
in scsi_finish_async_scan() will lead to shost be freed(because the
refcount of shost->shost_gendev decreases to 1 after USB disconnects),
at this point, if references shost again, system will show following
warning msg.

To make scsi_autopm_put_host(shost) always reference a valid shost,
put it just before scsi_host_put() in function
scsi_finish_async_scan().

[  299.281565] =============================================================================
[  299.281634] BUG kmalloc-4096 (Tainted: G          I ): Poison overwritten
[  299.281682] -----------------------------------------------------------------------------
[  299.281684]
[  299.281752] INFO: 0xffff880056c305d0-0xffff880056c305d0. First byte
0x6a instead of 0x6b
[  299.281816] INFO: Allocated in scsi_host_alloc+0x4a/0x490 age=1688
cpu=1 pid=2004
[  299.281870] 	__slab_alloc+0x617/0x6c1
[  299.281901] 	__kmalloc+0x28c/0x2e0
[  299.281931] 	scsi_host_alloc+0x4a/0x490
[  299.281966] 	usb_stor_probe1+0x5b/0xc40 [usb_storage]
[  299.282010] 	storage_probe+0xa4/0xe0 [usb_storage]
[  299.282062] 	usb_probe_interface+0x172/0x330 [usbcore]
[  299.282105] 	driver_probe_device+0x257/0x3b0
[  299.282138] 	__driver_attach+0x103/0x110
[  299.282171] 	bus_for_each_dev+0x8e/0xe0
[  299.282201] 	driver_attach+0x26/0x30
[  299.282230] 	bus_add_driver+0x1c4/0x430
[  299.282260] 	driver_register+0xb6/0x230
[  299.282298] 	usb_register_driver+0xe5/0x270 [usbcore]
[  299.282337] 	0xffffffffa04ab03d
[  299.282364] 	do_one_initcall+0x47/0x230
[  299.282396] 	sys_init_module+0xa0f/0x1fe0
[  299.282429] INFO: Freed in scsi_host_dev_release+0x18a/0x1d0 age=85
cpu=0 pid=2008
[  299.282482] 	__slab_free+0x3c/0x2a1
[  299.282510] 	kfree+0x296/0x310
[  299.282536] 	scsi_host_dev_release+0x18a/0x1d0
[  299.282574] 	device_release+0x74/0x100
[  299.282606] 	kobject_release+0xc7/0x2a0
[  299.282637] 	kobject_put+0x54/0xa0
[  299.282668] 	put_device+0x27/0x40
[  299.282694] 	scsi_host_put+0x1d/0x30
[  299.282723] 	do_scan_async+0x1fc/0x2b0
[  299.282753] 	kthread+0xdf/0xf0
[  299.282782] 	kernel_thread_helper+0x4/0x10
[  299.282817] INFO: Slab 0xffffea00015b0c00 objects=7 used=7 fp=0x
      (null) flags=0x100000000004080
[  299.282882] INFO: Object 0xffff880056c30000 @offset=0 fp=0x          (null)
[  299.282884]
...
Signed-off-by: NHuajun Li <huajun.li.lee@gmail.com>
Cc: stable@kernel.org
Acked-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patch (as1507) adds a skip_vpd_pages flag to struct scsi_device
and a no_report_luns flag to struct scsi_target.  The first is used to
control whether sd will look at VPD pages for information on block
provisioning, limits, and characteristics.  The second prevents
scsi_report_lun_scan() from issuing a REPORT LUNS command.

The patch also modifies usb-storage to set the new flag bits for all
USB devices and targets, and to stop adjusting the scsi_level value.

Historically we have seen that USB mass-storage devices often don't
support VPD pages or REPORT LUNS properly.  Until now we have avoided
these things by setting the scsi_level to SCSI_2 for all USB devices.
But this has the side effect of storing the LUN bits into the second
byte of each CDB, and now we have a report of a device which doesn't
like that.  The best solution is to stop abusing scsi_level and
instead have separate flags for VPD pages and REPORT LUNS.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Reported-by: NPerry Wagle <wagle@mac.com>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* 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: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

On Mon, 2011-11-07 at 17:24 +1100, Stephen Rothwell wrote:
> Hi all,
>
> Starting some time last week I am getting the following during boot on
> our PPC970 blade:
>
> calling  .ipr_init+0x0/0x68 @ 1
> ipr: IBM Power RAID SCSI Device Driver version: 2.5.2 (April 27, 2011)
> ipr 0000:01:01.0: Found IOA with IRQ: 26
> ipr 0000:01:01.0: Starting IOA initialization sequence.
> ipr 0000:01:01.0: Adapter firmware version: 06160039
> ipr 0000:01:01.0: IOA initialized.
> scsi0 : IBM 572E Storage Adapter
> ------------[ cut here ]------------
> WARNING: at drivers/scsi/scsi_lib.c:1704
> Modules linked in:
> NIP: c00000000053b3d4 LR: c00000000053e5b0 CTR: c000000000541d70
> REGS: c0000000783c2f60 TRAP: 0700   Not tainted  (3.1.0-autokern1)
> MSR: 8000000000029032 <EE,ME,CE,IR,DR>  CR: 24002024  XER: 20000002
> TASK = c0000000783b8000[1] 'swapper' THREAD: c0000000783c0000 CPU: 0
> GPR00: 0000000000000001 c0000000783c31e0 c000000000cf38b0 c00000000239a9d0
> GPR04: c000000000cbe8f8 0000000000000000 c0000000783c3040 0000000000000000
> GPR08: c000000075daf488 c000000078a3b7ff c000000000bcacc8 0000000000000000
> GPR12: 0000000044002028 c000000007ffb000 0000000002e40000 000000000099b800
> GPR16: 0000000000000000 c000000000bba5fc c000000000a61db8 0000000000000000
> GPR20: 0000000001b77200 0000000000000000 c000000078990000 0000000000000001
> GPR24: c000000002396828 0000000000000000 0000000000000000 c000000078a3b938
> GPR28: fffffffffffffffa c0000000008ad2c0 c000000000c7faa8 c00000000239a9d0
> NIP [c00000000053b3d4] .scsi_free_queue+0x24/0x90
> LR [c00000000053e5b0] .scsi_alloc_sdev+0x280/0x2e0
> Call Trace:
> [c0000000783c31e0] [c000000000c7faa8] wireless_seq_fops+0x278d0/0x2eb88 (unreliable)
> [c0000000783c3270] [c00000000053e5b0] .scsi_alloc_sdev+0x280/0x2e0
> [c0000000783c3330] [c00000000053eba0] .scsi_probe_and_add_lun+0x390/0xb40
> [c0000000783c34a0] [c00000000053f7ec] .__scsi_scan_target+0x16c/0x650
> [c0000000783c35f0] [c00000000053fd90] .scsi_scan_channel+0xc0/0x100
> [c0000000783c36a0] [c00000000053fefc] .scsi_scan_host_selected+0x12c/0x1c0
> [c0000000783c3750] [c00000000083dcb4] .ipr_probe+0x2c0/0x390
> [c0000000783c3830] [c0000000003f50b4] .local_pci_probe+0x34/0x50
> [c0000000783c38a0] [c0000000003f5f78] .pci_device_probe+0x148/0x150
> [c0000000783c3950] [c0000000004e1e8c] .driver_probe_device+0xdc/0x210
> [c0000000783c39f0] [c0000000004e20cc] .__driver_attach+0x10c/0x110
> [c0000000783c3a80] [c0000000004e1228] .bus_for_each_dev+0x98/0xf0
> [c0000000783c3b30] [c0000000004e1bf8] .driver_attach+0x28/0x40
> [c0000000783c3bb0] [c0000000004e07d8] .bus_add_driver+0x218/0x340
> [c0000000783c3c60] [c0000000004e2a2c] .driver_register+0x9c/0x1b0
> [c0000000783c3d00] [c0000000003f62d4] .__pci_register_driver+0x64/0x140
> [c0000000783c3da0] [c000000000b99f88] .ipr_init+0x4c/0x68
> [c0000000783c3e20] [c00000000000ad24] .do_one_initcall+0x1a4/0x1e0
> [c0000000783c3ee0] [c000000000b512d0] .kernel_init+0x14c/0x1fc
> [c0000000783c3f90] [c000000000022468] .kernel_thread+0x54/0x70
> Instruction dump:
> ebe1fff8 7c0803a6 4e800020 7c0802a6 fba1ffe8 fbe1fff8 7c7f1b78 f8010010
> f821ff71 e8030398 3120ffff 7c090110 <0b000000> e86303b0 482de065 60000000
> ---[ end trace 759bed76a85e8dec ]---
> scsi 0:0:1:0: Direct-Access     IBM-ESXS MAY2036RC        T106 PQ: 0 ANSI: 5
> ------------[ cut here ]------------
>
> I get lots more of these.  The obvious commit to point the finger at
> is 3308511c ("[SCSI] Make scsi_free_queue() kill pending SCSI
> commands") but the root cause may be something different.

Caused by

commit f7c9c6bb
Author: Anton Blanchard <anton@samba.org>
Date:   Thu Nov 3 08:56:22 2011 +1100

    [SCSI] Fix block queue and elevator memory leak in scsi_alloc_sdev

Doesn't completely do the teardown.  The true fix is to do a proper
teardown instead of hand rolling it
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Tested-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: stable@kernel.org	#2.6.38+
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When looking at memory consumption issues I noticed quite a
lot of memory in the kmalloc-2048 bucket:

  OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
  6561   6471  98%    2.30K    243       27     15552K kmalloc-2048

Over 15MB. slub debug shows that cfq is responsible for almost
all of it:

# sort -nr /sys/kernel/slab/kmalloc-2048/alloc_calls
6402 .cfq_init_queue+0xec/0x460 age=43423/43564/43655 pid=1 cpus=4,11,13

In scsi_alloc_sdev we do scsi_alloc_queue but if slave_alloc
fails we don't free it with scsi_free_queue.

The patch below fixes the issue:

  OBJS ACTIVE  USE OBJ SIZE  SLABS OBJ/SLAB CACHE SIZE NAME
   135     72  53%    2.30K      5       27       320K kmalloc-2048

# cat /sys/kernel/slab/kmalloc-2048/alloc_calls
3 .cfq_init_queue+0xec/0x460 age=3811/3876/3925 pid=1 cpus=4,11,13
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: <stable@kernel.org>		#2.6.38+
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In certain circumstances, we can get an oops from a torn down device.
Most notably this is from CD roms trying to call scsi_ioctl.  The root
cause of the problem is the fact that after scsi_remove_device() has
been called, the queue is fully torn down.  This is actually wrong
since the queue can be used until the sdev release function is called.
Therefore, we add an extra reference to the queue which is released in
sdev->release, so the queue always exists.
Reported-by: NParag Warudkar <parag.lkml@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NJames Bottomley <jbottomley@parallels.com>

Commit c21e6beb removed our queue request_fn re-enter
protection, and defaulted to always running the queues from
kblockd to be safe. This was a known potential slow down,
but should be safe.

Unfortunately this is causing big performance regressions for
some, so we need to improve this logic. Looking into the details
of the re-enter, the real issue is on requeue of requests.

Requeue of requests upon seeing a BUSY condition from the device
ends up re-running the queue, causing traces like this:

scsi_request_fn()
        scsi_dispatch_cmd()
                scsi_queue_insert()
                        __scsi_queue_insert()
                                scsi_run_queue()
					scsi_request_fn()
						...

potentially causing the issue we want to avoid. So special
case the requeue re-run of the queue, but improve it to offload
the entire run of local queue and starved queue from a single
workqueue callback. This is a lot better than potentially
kicking off a workqueue run for each device seen.

This also fixes the issue of the local device going into recursion,
since the above mentioned commit never moved that queue run out
of line.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

This patch removes the old CONFIG_SYSFS_DEPRECATED_V2 config option,
but it keeps the logic around to handle block devices in the old manner
as some people like to run new kernel versions on old (pre 2007/2008)
distros.
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: "James E.J. Bottomley" <James.Bottomley@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This patch (as1398b) adds runtime PM support to the SCSI layer.  Only
the machanism is provided; use of it is up to the various high-level
drivers, and the patch doesn't change any of them.  Except for sg --
the patch expicitly prevents a device from being runtime-suspended
while its sg device file is open.

The implementation is simplistic.  In general, hosts and targets are
automatically suspended when all their children are asleep, but for
them the runtime-suspend code doesn't actually do anything.  (A host's
runtime PM status is propagated up the device tree, though, so a
runtime-PM-aware lower-level driver could power down the host adapter
hardware at the appropriate times.)  There are comments indicating
where a transport class might be notified or some other hooks added.

LUNs are runtime-suspended by calling the drivers' existing suspend
handlers (and likewise for runtime-resume).  Somewhat arbitrarily, the
implementation delays for 100 ms before suspending an eligible LUN.
This is because there typically are occasions during bootup when the
same device file is opened and closed several times in quick
succession.

The way this all works is that the SCSI core increments a device's
PM-usage count when it is registered.  If a high-level driver does
nothing then the device will not be eligible for runtime-suspend
because of the elevated usage count.  If a high-level driver wants to
use runtime PM then it can call scsi_autopm_put_device() in its probe
routine to decrement the usage count and scsi_autopm_get_device() in
its remove routine to restore the original count.

Hosts, targets, and LUNs are not suspended while they are being probed
or removed, or while the error handler is running.  In fact, a fairly
large part of the patch consists of code to make sure that things
aren't suspended at such times.

[jejb: fix up compile issues in PM config variations]
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

This patch (as1357) fixes a race in SCSI target allocation and
release.  Putting a target in the STARGET_DEL state isn't protected by
the host lock, so an old target structure could be reused by a new
device even though it's about to be deleted.  The cure is to change
the state while still holding the host lock.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

scsi_scan.c: fix incorrectly formatted kernel-doc notation
& convert documentation of 2 functions into kernel-doc.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch (as1359) fixes a bug in scsi_alloc_target().  After a
device structure has been initialized (and especially after its name
has been set), it must not be freed directly.  One has to call
put_device() instead.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

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: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

The block layer calling convention is blk_queue_<limit name>.
blk_queue_max_sectors predates this practice, leading to some confusion.
Rename the function to appropriately reflect that its intended use is to
set max_hw_sectors.

Also introduce a temporary wrapper for backwards compability.  This can
be removed after the merge window is closed.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

This patch (as1334) fixes a bug in scsi_get_host_dev().  It
incorrectly calls get_device() on the new device's target.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

This patch (as1333) fixes a bug in scsi_report_lun_scan().  If a
newly-allocated device can't be used, it should be deleted.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

Current FC HBA queue_depth ramp up code depends on last queue
full time. The sdev already  has last_queue_full_time field to
track last queue full time but stored value is truncated by
last four bits.

So this patch updates last_queue_full_time without truncating
last 4 bits to store full value and then updates its only
current usages in scsi_track_queue_full to ignore last four bits
to keep current usages same while also use this field
in added ramp up code.

Adds scsi_handle_queue_ramp_up to ramp up queue_depth on
successful completion of IO. The scsi_handle_queue_ramp_up will
do ramp up on all luns of a target, just same as ramp down done
on all luns on a target.

The ramp up is skipped in case the change_queue_depth is not
supported by LLD or already reached to added max_queue_depth.

Updates added max_queue_depth on every new update to default
queue_depth value.

The ramp up is also skipped if lapsed time since either last
queue ramp up or down is less than LLD specified
queue_ramp_up_period.

Adds queue_ramp_up_period to sysfs but only if change_queue_depth
is supported since ramp up and queue_ramp_up_period is needed only
in case change_queue_depth is supported first.

Initializes queue_ramp_up_period to 120HZ jiffies as initial
default value, it is same as used in existing lpfc and qla2xxx.

-v2
 Combined all ramp code into this single patch.

-v3
 Moves max_queue_depth initialization after slave_configure is
called from after slave_alloc calling done. Also adjusted
max_queue_depth check to skip ramp up if current queue_depth
is >= max_queue_depth.

-v4
 Changes sdev->queue_ramp_up_period unit to ms when using sysfs i/f
to store or show its value.
Signed-off-by: NVasu Dev <vasu.dev@intel.com>
Tested-by: NChristof Schmitt <christof.schmitt@de.ibm.com>
Tested-by: NGiridhar Malavali <giridhar.malavali@qlogic.com>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

Async scanning introduced a very wide window where the SCSI device is
up and running but has not yet been added to sysfs.  We delay the
adding until all scans have completed to retain the same ordering as
sync scanning.

This delay in visibility causes an oops if a device is removed before
we make it visible because the SCSI removal routines have an inbuilt
assumption that if a device is in SDEV_RUNNING state, it must be
visible (which is not necessarily true in the async scanning case).

Fix this by introducing an additional is_visible flag which we can use
to condition the tear down so we do the right thing for running but
not yet made visible.
Reported-by: NAlexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

The root cause of the problem is the fact that dev_set_name() now
allocates storage instead of using the original array within the kobj.
That means that the SCSI assumption that if you haven't made the
containing object or any sub objects visible, you can just destroy it
(and its component devices) lock stock and barrel becomes false.

Fix this by doing the get of sdev_dev at parent time and thus do an
extra put of it in scsi_destroy_sdev() (and all other destruction
without add paths).
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@suse.de>

This patch (as1224) changes the default timeout for INQUIRY commands
from 3 seconds to 20 seconds, which is the value used by Windows for
USB Mass-Storage devices.  Some of these devices, like the Corsair
Flash Voyager (see Bugzilla #12188) really do need a long timeout.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch initializes the max_target_blocked field of a scsi target
structure so that a queuecommand return value of
SCSI_MLQUEUE_TARGET_BUSY will actually result in having the
scsi_queue_insert blocking the device queue before requeuing the
command and running the queue.  Otherwise, can and does cause livelock
on single CPU configurations if/when open-iSCSI software initiator's
command PDU window fills.
Signed-off-by: NEd Goggin <egoggin@vmware.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

There is currently only one way for userspace to say "wait for my storage
device to get ready for the modules I just loaded": to load the
scsi_wait_scan module. Expectations of userspace are that once this
module is loaded, all the (storage) devices for which the drivers
were loaded before the module load are present.

Now, there are some issues with the implementation, and the async
stuff got caught in the middle of this: The existing code only
waits for the scsy async probing to finish, but it did not take
into account at all that probing might not have begun yet.
(Russell ran into this problem on his computer and the fix works for him)

This patch fixes this more thoroughly than the previous "fix", which
had some bad side effects (namely, for kernel code that wanted to wait for
the scsi scan it would also do an async sync, which would deadlock if you did
it from async context already.. there's a report about that on lkml):
The patch makes the module first wait for all device driver probes, and then it
will wait for the scsi parallel scan to finish.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Tested-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Define the OSD_TYPE scsi device and let it show up in scans
Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

We were running i/o and performing a bunch of hba resets in a loop.
This forces a lot of target removes and then rescans. Since the
resets are occuring during scan it's causing the scan i/o to timeout,
invoking error recovery, etc.  We end up getting some nasty crashing
in scsi_scan.c due to references to old sdevs that are failing
but had some lingering references that kept them around.

Fix by setting device state to SDEV_DEL if the LLD's slave_alloc
fails.
Signed-off-by: NJames Smart <james.smart@emulex.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch makes part of the scsi probe (which is mostly device spin up and the
partition scan) asynchronous. Only the part that runs after getting the device
number allocated is asynchronous, ensuring that device numbering remains stable.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>

[jejb: limit ioctl to returning 20 characters to avoid overrun
       on long device names and add a few more conversions]
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

This patch changes scsi_probe_lun() to retry INQUIRY if the device has
not actually sent back any INQUIRY data,

This enables the Thecus N2050 storage device to work better. The
firmware on that device starts up strangely; it sends no data in
response to the initial INQUIRY, and it sends the INQUIRY information
in response to the followup REQUEST SENSE. But after that it works
better, so retrying the INQUIRY is enough to get it going.
Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>