This patch checks to see if an ATA device supports NCQ command priorities.
If so and the user has specified an iocontext that indicates
IO_PRIO_CLASS_RT then we build a tf with a high priority command.

This is done to improve the tail latency of commands that are high
priority by passing priority to the device.

tj: Removed trivial ata_ncq_prio_enabled() and open-coded the test.
Signed-off-by: NAdam Manzanares <adam.manzanares@hgst.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

asm-generic is only intended for architecture defaults, and we can simply
kill it off by moving the two defintions directly to <linux/libata.h>.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

This avoid the need to always translate between the two in ata_prot_flags
and generally cleans up the taskfile protocol usage.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

Instead we can simply check for PIO or DMA in ata_is_data.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

The only caller can just check for !ata_is_data instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

Add a new taskfile protocol ATA_PROT_NCQ_NODATA to handle
ATA NCQ NO-DATA commands correctly.
And fixup ata_scsi_zbc_out_xlat() to use it.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

This way we don't have to worry about the exact bit postition of the
test to leak out and any crazy propagation effects in the callers.
Suggested-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

Byte 69 bits 0:1 in the IDENTIFY DEVICE data indicate a
host-aware ZAC device.
Host-managed ZAC devices have their own individual signature,
and to not set the bits in the IDENTIFY DEVICE data.
And whenever we detect a ZAC-compatible device we should
be displaying the zoned block characteristics VPD page.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

Add NCQ encapsulation for ZAC MANAGEMENT OUT and evaluate
NCQ Non-Data log pages to figure out if NCQ encapsulation
is supported.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

ZAC drives implement a 'ZAC Management In' command template,
which maps onto the ZBC IN command.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

libata device disabling is ... curious. So add the correct
definitions that we can disable ZAC devices properly.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

ACS-4 defines an NCQ encapsulation for READ LOG DMA EXT.
Signed-off-by: NHannes Reinecke <hare@suse.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Implement MODE SELECT for the control mode page to allow the OS
to switch to descriptor sense.

tj: Dropped s/sb/cmd->sense_buffer/ in ata_gen_ata_sense().  Added
    @dev description to ata_msense_ctl_mode().
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

The id buffer in ata_device is a DMA target, but it isn't explicitly
cacheline aligned. Due to this, adjacent fields can be overwritten with
stale data from memory on non coherent architectures. As a result, the
kernel is sometimes unable to communicate with an ATA device.

Fix this by ensuring that the id buffer is cacheline aligned.

This issue is similar to that fixed by Commit 84bda12a
("libata: align ap->sector_buf").
Signed-off-by: NHarvey Hunt <harvey.hunt@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org> # 2.6.18
Signed-off-by: NTejun Heo <tj@kernel.org>

The AHCI driver code stops and starts port DMA engines at will
without considering the power state of the particular port. The
AHCI specification isn't very clear on how to handle this scenario,
leaving implementation open to interpretation.

Broadcom's STB SATA host controller is unable to handle port DMA
controller restarts when the port in question is in low power mode.
When a port enters partial or slumber mode, its PHY is powered down.
When a controller restart is requested, the controller's internal
state machine expects the PHY to be brought back up by software which
never happens in this case, resulting in failures.

To avoid this situation, logic is added to manually wake up the port
just before its DMA engine is stopped, if the port happens to be in
a low power state. HBA initiated power management ensures that the port
eventually returns to its configured low power state, when the link is
idle (as per the conditions listed in the spec). A new host flag is also
added to ensure this logic is only exercised for hosts with the above
limitation.

tj: Formatting changes.
Signed-off-by: NDanesh Petigara <dpetigara@broadcom.com>
Reviewed-by: NMarkus Mayer <mmayer@broadcom.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

The link resume logic uses a 200msec delay while debouncing
the SControl register. The rationale behind that delay is
to accommodate some PHYs that behave badly if their SStatus/
SControl registers are pounded immediately on resume.
The Broadcom STB SATA PHY does not seem to have this issue.
This patch introduces a new link flag that allows platforms
to skip the debounce delay if it isn't needed.
Signed-off-by: NDanesh Petigara <dpetigara@broadcom.com>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Some controller lockup on a ata_read_log_page.
Add new ata port flag ATA_FLAG_NO_LOG_PAGE which can used
to blacklist a controller.

If this flag is set, any attempt to read a log page returns an error
without actually issuing the command.
Signed-off-by: NAndreas Werner <andreas.werner@men.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

If the AHCI ports' HPCP or ESP bits are set, the port
should be considered external (e.g. eSATA) and is marked
as removable.  Userspace tools like udisks then treat it
like an usb drive.

With this patch applied, when I plug a drive into the esata port,
KDE pops up a window asking what to do with the drives(s), just
like it does for any random USB stick.

Removability is indicated to the upper layers by way of the
SCSI RMB bit, as I haven't found another way to signal
userspace to treat a sata disk like any usb stick.
Signed-off-by: NManuel Lauss <manuel.lauss@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Since no longer limiting max_sectors to BLK_DEF_MAX_SECTORS (commit 34b48db6),
data corruption may occur on ST380013AS drive configured on 82801JI (ICH10 Family)
SATA controller. This patch will allow the driver to limit max_sectors as before

 # cat /sys/block/sdb/queue/max_sectors_kb
 512

I was able to double the max_sectors_kb value up to 16384 on linux-4.2.0-rc2
before seeing corruption, but seems safer to use previous limit. Without this
patch max_sectors_kb will be 32767.

tj: Minor comment update.
Reported-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NDavid Milburn <dmilburn@redhat.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org # v3.19 and later
Fixes: 34b48db6 ("block: remove artifical max_hw_sectors cap")

Some devices lose data on TRIM whether queued or not.  This patch adds
a horkage to disable TRIM.

tj: Collapsed unnecessary if() nesting.
Signed-off-by: NArne Fitzenreiter <arne_f@ipfire.org>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org

'0' is now used as the default cmd_per_lun value,
so there's no need to explicitly set it to '1' in the
host template.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Some devices advertise support for the READ/WRITE LOG DMA EXT commands
but fail when we try to issue them. This can lead to queued TRIM being
unintentionally disabled since the relevant feature flag is located in a
general purpose log page.

Fall back to unqueued READ LOG EXT if the DMA variant fails while
reading a log page.
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

When the LPM policy is set to ATA_LPM_MAX_POWER, the device might
generate a spurious PHY event that cuases errors on the link.
Ignore this event if it occured within 10s after the policy change.

The timeout was chosen observing that on a Dell XPS13 9333 these
spurious events can occur up to roughly 6s after the policy change.

Link: http://lkml.kernel.org/g/3352987.ugV1Ipy7Z5@xps13Signed-off-by: NGabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org

This is a preparation commit that will allow to add other criteria
according to which PHY events should be dropped.
Signed-off-by: NGabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org

sata_sil24 for some reason pukes when tags are allocated round-robin
which helps tag ordered controllers.  To work around the issue,
72dd299d ("libata: allow sata_sil24 to opt-out of tag ordered
submission") introduced ATA_FLAG_LOWTAG which tells libata tag
allocation to do lowest-first.

However, with the recent switch to blk-mq tag allocation, the liata
tag allocation code path is no longer used and the workaround is now
implemented in the block layer and selected by setting
scsi_host_template->tag_alloc_policy to BLK_TAG_ALLOC_FIFO.  See
9269e234 ("libata: make sata_sil24 use fifo tag allocator").

This leaves ATA_FLAG_LOWTAG withoout any actual user.  Remove it.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Shaohua Li <shli@fb.com>
Cc: Dan Williams <dan.j.williams@intel.com>

SAS controller has its own tag allocation, which doesn't directly match to ATA
tag, so SAS and SATA have different code path for ata tags. Originally we use
port->scsi_host (98bd4be1) to destinguish SAS controller, but libsas set
->scsi_host too, so we can't use it for the destinguish, we add a new flag for
this purpose.

Without this patch, the following oops can happen because scsi-mq uses
a host-wide tag map shared among all devices with some integer tag
values >= ATA_MAX_QUEUE.  These unexpectedly high tag values cause
__ata_qc_from_tag() to return NULL, which is then dereferenced in
ata_qc_new_init().

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
  IP: [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
  PGD 32adf0067 PUD 32adf1067 PMD 0
  Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
  Modules linked in: iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi igb
  i2c_algo_bit ptp pps_core pm80xx libsas scsi_transport_sas sg coretemp
  eeprom w83795 i2c_i801
  CPU: 4 PID: 1450 Comm: cydiskbench Not tainted 4.0.0-rc3 #1
  Hardware name: Supermicro X8DTH-i/6/iF/6F/X8DTH, BIOS 2.1b       05/04/12
  task: ffff8800ba86d500 ti: ffff88032a064000 task.ti: ffff88032a064000
  RIP: 0010:[<ffffffff804fd46e>]  [<ffffffff804fd46e>] ata_qc_new_init+0x3e/0x120
  RSP: 0018:ffff88032a067858  EFLAGS: 00010046
  RAX: 0000000000000000 RBX: ffff8800ba0d2230 RCX: 000000000000002a
  RDX: ffffffff80505ae0 RSI: 0000000000000020 RDI: ffff8800ba0d2230
  RBP: ffff88032a067868 R08: 0000000000000201 R09: 0000000000000001
  R10: 0000000000000000 R11: 0000000000000000 R12: ffff8800ba0d0000
  R13: ffff8800ba0d2230 R14: ffffffff80505ae0 R15: ffff8800ba0d0000
  FS:  0000000041223950(0063) GS:ffff88033e480000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000058 CR3: 000000032a0a3000 CR4: 00000000000006e0
  Stack:
   ffff880329eee758 ffff880329eee758 ffff88032a0678a8 ffffffff80502dad
   ffff8800ba167978 ffff880329eee758 ffff88032bf9c520 ffff8800ba167978
   ffff88032bf9c520 ffff88032bf9a290 ffff88032a0678b8 ffffffff80506909
  Call Trace:
   [<ffffffff80502dad>] ata_scsi_translate+0x3d/0x1b0
   [<ffffffff80506909>] ata_sas_queuecmd+0x149/0x2a0
   [<ffffffffa0046650>] sas_queuecommand+0xa0/0x1f0 [libsas]
   [<ffffffff804ea544>] scsi_dispatch_cmd+0xd4/0x1a0
   [<ffffffff804eb50f>] scsi_queue_rq+0x66f/0x7f0
   [<ffffffff803e5098>] __blk_mq_run_hw_queue+0x208/0x3f0
   [<ffffffff803e54b8>] blk_mq_run_hw_queue+0x88/0xc0
   [<ffffffff803e5c74>] blk_mq_insert_request+0xc4/0x130
   [<ffffffff803e0b63>] blk_execute_rq_nowait+0x73/0x160
   [<ffffffffa0023fca>] sg_common_write+0x3da/0x720 [sg]
   [<ffffffffa0025100>] sg_new_write+0x250/0x360 [sg]
   [<ffffffffa0025feb>] sg_write+0x13b/0x450 [sg]
   [<ffffffff8032ec91>] vfs_write+0xd1/0x1b0
   [<ffffffff8032ee54>] SyS_write+0x54/0xc0
   [<ffffffff80689932>] system_call_fastpath+0x12/0x17

tj: updated description.

Fixes: 12cb5ce1 ("libata: use blk taging")
Reported-and-tested-by: NTony Battersby <tonyb@cybernetics.com>
Signed-off-by: NShaohua Li <shli@fb.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

The owner module reference of the ahci platform's scsi_host is
initialized to libahci_platform's one, because these drivers use a
scsi_host_template defined in libahci_platform.  So these drivers can
be unloaded even if the scsi device is being accessed.

This fixes it by pushing the scsi_host_template from libahci_platform
to all leaf drivers.  The scsi_host_template is passed through a new
argument of ahci_platform_init_host().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: linux-ide@vger.kernel.org
Cc: linux-scsi@vger.kernel.org

libata uses its own tag management which is duplication and the
implementation is poor. And if we switch to blk-mq, tag is build-in.
It's time to switch to generic taging.

The SAS driver has its own tag management, and looks we can't directly
map the host controler tag to SATA tag. So I just bypassed the SAS case.

I changed the code/variable name for the tag management of libata to
make it self contained. Only sas will use it. Later if libsas implements
its tag management, the tag management code in libata can be deleted
easily.

Cc: Jens Axboe <axboe@fb.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: NShaohua Li <shli@fb.com>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

Ronny reports: https://bugzilla.kernel.org/show_bug.cgi?id=87101
    "Since commit 8a4aeec8 "libata/ahci: accommodate tag ordered
    controllers" the access to the harddisk on the first SATA-port is
    failing on its first access. The access to the harddisk on the
    second port is working normal.

    When reverting the above commit, access to both harddisks is working
    fine again."

Maintain tag ordered submission as the default, but allow sata_sil24 to
continue with the old behavior.

Cc: <stable@vger.kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Reported-by: NRonny Hegewald <Ronny.Hegewald@online.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

As defined, the DRAT (Deterministic Read After Trim) and RZAT (Return
Zero After Trim) flags in the ATA Command Set are unreliable in the
sense that they only define what happens if the device successfully
executed the DSM TRIM command. TRIM is only advisory, however, and the
device is free to silently ignore all or parts of the request.

In practice this renders the DRAT and RZAT flags completely useless and
because the results are unpredictable we decided to disable discard in
MD for 3.18 to avoid the risk of data corruption.

Hardware vendors in the real world obviously need better guarantees than
what the standards bodies provide. Unfortuntely those guarantees are
encoded in product requirements documents rather than somewhere we can
key off of them programatically. So we are compelled to disabling
discard_zeroes_data for all devices unless we explicitly have data to
support whitelisting them.

This patch whitelists SSDs from a few of the main vendors. None of the
whitelists are based on written guarantees. They are purely based on
empirical evidence collected from internal and external users that have
tested or qualified these drives in RAID deployments.

The whitelist is only meant as a starting point and is by no means
comprehensive:

   - All intel SSD models except for 510
   - Micron M5?0/M600
   - Samsung SSDs
   - Seagate SSDs
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

Drop the now unused reason argument from the ->change_queue_depth method.
Also add a return value to scsi_adjust_queue_depth, and rename it to
scsi_change_queue_depth now that it can be used as the default
->change_queue_depth implementation.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

Add new ATA device type for ZAC devices.
Acked-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NTejun Heo <tj@kernel.org>

The return value is not used by callers of these functions nor
by uses of all macros so change the functions to return void.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

1871ee13 ("libata: support the ata host which implements a queue
depth less than 32") directly used ata_port->scsi_host->can_queue from
ata_qc_new() to determine the number of tags supported by the host;
unfortunately, SAS controllers doing SATA don't initialize ->scsi_host
leading to the following oops.

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000058
 IP: [<ffffffff814e0618>] ata_qc_new_init+0x188/0x1b0
 PGD 0
 Oops: 0002 [#1] SMP
 Modules linked in: isci libsas scsi_transport_sas mgag200 drm_kms_helper ttm
 CPU: 1 PID: 518 Comm: udevd Not tainted 3.16.0-rc6+ #62
 Hardware name: Intel Corporation S2600CO/S2600CO, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
 task: ffff880c1a00b280 ti: ffff88061a000000 task.ti: ffff88061a000000
 RIP: 0010:[<ffffffff814e0618>]  [<ffffffff814e0618>] ata_qc_new_init+0x188/0x1b0
 RSP: 0018:ffff88061a003ae8  EFLAGS: 00010012
 RAX: 0000000000000001 RBX: ffff88000241ca80 RCX: 00000000000000fa
 RDX: 0000000000000020 RSI: 0000000000000020 RDI: ffff8806194aa298
 RBP: ffff88061a003ae8 R08: ffff8806194a8000 R09: 0000000000000000
 R10: 0000000000000000 R11: ffff88000241ca80 R12: ffff88061ad58200
 R13: ffff8806194aa298 R14: ffffffff814e67a0 R15: ffff8806194a8000
 FS:  00007f3ad7fe3840(0000) GS:ffff880627620000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000000000000058 CR3: 000000061a118000 CR4: 00000000001407e0
 Stack:
  ffff88061a003b20 ffffffff814e96e1 ffff88000241ca80 ffff88061ad58200
  ffff8800b6bf6000 ffff880c1c988000 ffff880619903850 ffff88061a003b68
  ffffffffa0056ce1 ffff88061a003b48 0000000013d6e6f8 ffff88000241ca80
 Call Trace:
  [<ffffffff814e96e1>] ata_sas_queuecmd+0xa1/0x430
  [<ffffffffa0056ce1>] sas_queuecommand+0x191/0x220 [libsas]
  [<ffffffff8149afee>] scsi_dispatch_cmd+0x10e/0x300
  [<ffffffff814a3bc5>] scsi_request_fn+0x2f5/0x550
  [<ffffffff81317613>] __blk_run_queue+0x33/0x40
  [<ffffffff8131781a>] queue_unplugged+0x2a/0x90
  [<ffffffff8131ceb4>] blk_flush_plug_list+0x1b4/0x210
  [<ffffffff8131d274>] blk_finish_plug+0x14/0x50
  [<ffffffff8117eaa8>] __do_page_cache_readahead+0x198/0x1f0
  [<ffffffff8117ee21>] force_page_cache_readahead+0x31/0x50
  [<ffffffff8117ee7e>] page_cache_sync_readahead+0x3e/0x50
  [<ffffffff81172ac6>] generic_file_read_iter+0x496/0x5a0
  [<ffffffff81219897>] blkdev_read_iter+0x37/0x40
  [<ffffffff811e307e>] new_sync_read+0x7e/0xb0
  [<ffffffff811e3734>] vfs_read+0x94/0x170
  [<ffffffff811e43c6>] SyS_read+0x46/0xb0
  [<ffffffff811e33d1>] ? SyS_lseek+0x91/0xb0
  [<ffffffff8171ee29>] system_call_fastpath+0x16/0x1b
 Code: 00 00 00 88 50 29 83 7f 08 01 19 d2 83 e2 f0 83 ea 50 88 50 34 c6 81 1d 02 00 00 40 c6 81 17 02 00 00 00 5d c3 66 0f 1f 44 00 00 <89> 14 25 58 00 00 00

Fix it by introducing ata_host->n_tags which is initialized to
ATA_MAX_QUEUE - 1 in ata_host_init() for SAS controllers and set to
scsi_host_template->can_queue in ata_host_register() for !SAS ones.
As SAS hosts are never registered, this will give them the same
ATA_MAX_QUEUE - 1 as before.  Note that we can't use
scsi_host->can_queue directly for SAS hosts anyway as they can go
higher than the libata maximum.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NMike Qiu <qiudayu@linux.vnet.ibm.com>
Reported-by: NJesse Brandeburg <jesse.brandeburg@gmail.com>
Reported-by: NPeter Hurley <peter@hurleysoftware.com>
Reported-by: NPeter Zijlstra <peterz@infradead.org>
Tested-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Fixes: 1871ee13 ("libata: support the ata host which implements a queue depth less than 32")
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org

The AHCI spec allows implementations to issue commands in tag order
rather than FIFO order:

	5.3.2.12 P:SelectCmd
	HBA sets pSlotLoc = (pSlotLoc + 1) mod (CAP.NCS + 1)
	or HBA selects the command to issue that has had the
	PxCI bit set to '1' longer than any other command
	pending to be issued.

The result is that commands posted sequentially (time-wise) may play out
of sequence when issued by hardware.

This behavior has likely been hidden by drives that arrange for commands
to complete in issue order.  However, it appears recent drives (two from
different vendors that we have found so far) inflict out-of-order
completions as a matter of course.  So, we need to take care to maintain
ordered submission, otherwise we risk triggering a drive to fall out of
sequential-io automation and back to random-io processing, which incurs
large latency and degrades throughput.

This issue was found in simple benchmarks where QD=2 seq-write
performance was 30-50% *greater* than QD=32 seq-write performance.

Tagging for -stable and making the change globally since it has a low
risk-to-reward ratio.  Also, word is that recent versions of an unnamed
OS also does it this way now.  So, drives in the field are already
experienced with this tag ordering scheme.

Cc: <stable@vger.kernel.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Ed Ciechanowski <ed.ciechanowski@intel.com>
Reviewed-by: NMatthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Commit bc6e7c4b "libata, libsas: kill pm_result and related cleanup"
renamed ata_sas_port_async_resume() to ata_sas_port_resume(), but missed
a CONFIG_PM=n stub conversion.  Randy fixed that up in commit
a5a65699 "libata.h: add stub for ata_sas_port_resume", but missed
the deletion of the now unused ata_sas_port_async_resume() routine.

Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

Fix build error when CONFIG_PM is not enabled by adding a stub
function in <linux/libata.h>.

drivers/scsi/libsas/sas_ata.c: In function 'sas_resume_sata':
drivers/scsi/libsas/sas_ata.c:756:3: error: implicit declaration of function 'ata_sas_port_resume' [-Werror=implicit-function-declaration]
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Reported-by: NJim Davis <jim.epost@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>

Tejun says:
  "At least for libata, worrying about suspend/resume failures don't make
   whole lot of sense.  If suspend failed, just proceed with suspend.  If
   the device can't be woken up afterwards, that's that.  There isn't
   anything we could have done differently anyway.  The same for resume, if
   spinup fails, the device is dud and the following commands will invoke
   EH actions and will eventually fail.  Again, there really isn't any
   *choice* to make.  Just making sure the errors are handled gracefully
   (ie. don't crash) and the following commands are handled correctly
   should be enough."

The only libata user that actually cares about the result from a suspend
operation is libsas.  However, it only cares about whether queuing a new
operation collides with an in-flight one.  All libsas does with the
error is retry, but we can just let libata wait for the previous
operation before continuing.

Other cleanups include:
1/ Unifying all ata port pm operations on an ata_port_pm_ prefix
2/ Marking all ata port pm helper routines as returning void, only
   ata_port_pm_ entry points need to fake a 0 return value.
3/ Killing ata_port_{suspend|resume}_common() in favor of calling
   ata_port_request_pm() directly
4/ Killing the wrappers that just do a to_ata_port() conversion
5/ Clearly marking the entry points that do async operations with an
  _async suffix.

Reference: http://marc.info/?l=linux-scsi&m=138995409532286&w=2

Cc: Phillip Susi <psusi@ubuntu.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Suggested-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NTodd Brandt <todd.e.brandt@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

For some reason, some early WD drives spin up and down drives
erratically when the link is put into slumber mode which can reduce
the life expectancy of the device significantly.  Unfortunately, we
don't have full list of devices and given the nature of the issue it'd
be better to err on the side of false positives than the other way
around.  Let's disable LPM on all WD devices which match one of the
known problematic model prefixes and are SATA-I.

As horkage list doesn't support matching SATA capabilities, this is
implemented as two horkages - WD_BROKEN_LPM and NOLPM.  The former is
set for the known prefixes and sets the latter if the matched device
is SATA-I.

Note that this isn't optimal as this disables all LPM operations and
partial link power state reportedly works fine on these; however, the
way LPM is implemented in libata makes it difficult to precisely map
libata LPM setting to specific link power state.  Well, these devices
are already fairly outdated.  Let's just disable whole LPM for now.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-and-tested-by: NNikos Barkas <levelwol@gmail.com>
Reported-and-tested-by: NIoannis Barkas <risc4all@yahoo.com>
References: https://bugzilla.kernel.org/show_bug.cgi?id=57211
Cc: stable@vger.kernel.org

Certain drives cannot handle queued TRIM commands properly, even
though support is indicated in the IDENTIFY DEVICE buffer.  This patch
allows for disabling the commands for the affected drives and apply it
to the Micron/Crucial M500 SSDs which exhibit incorrect protocol
behavior when issued queued TRIM commands, which could lead to silent
data corruption.

tj: Merged two unnecessarily split patches and made minor edits
    including shortening horkage name.
Signed-off-by: NMarc Carino <marc.ceeeee@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/g/1387246554-7311-1-git-send-email-marc.ceeeee@gmail.com
Cc: stable@vger.kernel.org # 3.12+