Rework alua_check_vpd() to use scsi_vpd_get_tpg()
and move the port group selection into the function, too.
With that we can simplify alua_initialize() to just
call alua_check_tpgs() and alua_check_vpd();
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use scsi_vpd_lun_id() to assign a unique device identification
to the alua port group structure.
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The port group needs to be a separate structure as several
LUNs might belong to the same group.
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The RTPG buffer will only evaluated within alua_rtpg(),
so we can allocate it locally there and avoid having to
put it into the global structure.
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

All commands are issued synchronously, so no need to open-code
scsi_execute_req_flags() anymore. And we can get rid of the
static sense code structure element. scsi_execute_req_flags()
will be setting REQ_QUIET and REQ_PREEMPT, but that is
perfectly fine as we're evaluating and logging any errors
ourselves and we really need to send the command even if
the device is quiesced.
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

If the call to SET TARGET PORT GROUPS fails we have no idea what
state the array is left in, so we need to issue a call to
REPORT TARGET PORT GROUPS in these cases.
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The 'activate_complete' function needs to be executed after
stpg has finished, so we can as well execute stpg synchronously
and call the function directly.
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Separate out SET TARGET PORT GROUP functionality into a separate
function alua_stpg().
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Pass in the buffer as a function argument for submit_rtpg().
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

With commit 83ea0e5e ("scsi_dh_alua: use scsi_vpd_tpg_id()") these
variables became obsolete, but weren't removed.

[mkp: Fixed checkpatch warning]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use the common function 'scsi_vpd_tpg_id()' instead of open-coding
it in scsi_dh_alua.

[mkp: Applied by hand]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Most sense code is already handled in the generic
code, so we shouldn't be adding special cases here.
However, when doing so we need to check for
unit attention whenever we're sending an internal
command.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Instead of returning an error code in alua_check_tpgs() we should
rather return the tpgs mode directly and have a cleaner syntax.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use 'get_unaligned_XX' and 'put_unaligned_XX' instead of
open-coding it.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

We should be using a flag when RTPG extended header is not
supported, that saves us sending RTPG twice for older arrays.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Fixup copy-and-paste error in the description of stpg_endio().
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Fixup submit_rtpg() to always return a standard SCSI return code.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Use standard logging functions instead of hand-crafted ones.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NEwan Milne <emilne@redhat.com>
Reviewed-by: NBart Van Assche <bvanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The only check for a valid sense code is calling scsi_normalize_sense()
and check the return value. So drop the pointless checks and rely on
scsi_normalize_sense() to figure out if the sense code is valid.
With that we can also remove the 'senselen' field.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.com>
Reviewed-by: NBart van Assche <bvanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Issue different logging messages if ALUA is not supported
or the TPGS setting is invalid.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The SCSI device now has the VPD page 0x83 information attached,
so there is no need to query it again.

[mkp: Fixed a checkpatch warning]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Non-disk devices might support ALUA, but the firmware
implementation is untested and frequently broken.
As we're don't actually need it disable ALUA support
for non-disk device for now.
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NBart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Add a ->handler and a ->handler_data field to struct scsi_device and kill
this indirection.  Also move struct scsi_device_handler to scsi_dh.h so that
changes to it don't require rebuilding every SCSI LLDD.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Add a single list of devices that need non-ALUA device handlers to the core
scsi_dh code so that we can autoload the modules for them at probe time.

While this is a little ugly in terms of architecture it actually
significantly simplifies the code in addition to the new autoloading
functionality.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Acked-by: NMike Snitzer <snitzer@redhat.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Move all code to set up and tear down sdev->scsi_dh_data to common code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

We need to grab a reference to the module before calling the attach
routines to avoid a small race vs module removal.  It also cleans up
the code significantly as a side effect.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>

This patch fixes an issue with multipath ipr SAS devices which require a
start unit command to be issued following an adapter reset. Without this
patch, paths get marked failed following an adapter reset and since the
error handler never gets invoked to issue the start unit, the paths are
never recovered. Returning FAILED for this case ensures the error
handler wakes up to issue the start unit.
Signed-off-by: NBrian King <brking@linux.vnet.ibm.com>
Tested-by: NWen Xiong <wenxiong@linux.vnet.ibm.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The blk_get_request function may fail in low-memory conditions or during
device removal (even if __GFP_WAIT is set). To distinguish between these
errors, modify the blk_get_request call stack to return the appropriate
ERR_PTR. Verify that all callers check the return status and consider
IS_ERR instead of a simple NULL pointer check.

For consistency, make a similar change to the blk_mq_alloc_request leg
of blk_get_request.  It may fail if the queue is dead, or the caller was
unwilling to wait.
Signed-off-by: NJoe Lawrence <joe.lawrence@stratus.com>
Acked-by: Jiri Kosina <jkosina@suse.cz> [for pktdvd]
Acked-by: Boaz Harrosh <bharrosh@panasas.com> [for osd]
Reviewed-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

With the optimizations around not clearing the full request at alloc
time, we are leaving some of the needed init for REQ_TYPE_BLOCK_PC
up to the user allocating the request.

Add a blk_rq_set_block_pc() that sets the command type to
REQ_TYPE_BLOCK_PC, and properly initializes the members associated
with this type of request. Update callers to use this function instead
of manipulating rq->cmd_type directly.

Includes fixes from Christoph Hellwig <hch@lst.de> for my half-assed
attempt.
Signed-off-by: NJens Axboe <axboe@fb.com>

During testing, it was discovered that when a device tries to attach to the
alua handler while in TPG state of transitioning, the alua_rtpg function will
wait for it to exit the state before allowing it to continue. As a result, if
the 60 second timeout expires, the alua handler will not attach to the device.

To fix this, I have introduced an input argument to alua_rtpg called
wait_for_transition.  The idea is that it will wait for the transition to
complete before an activation (because the current TPG state has some bearing
in that case), but during a discovery if it is transitioning, it will not
wait, and will store the state as standby for the time being.

I believe the precedent exists for this from commit
c0d289b3 Since if the device reports a state
of transitioning, it can transition to other more valid states, and it has
been established TPGS is supported on the device, if it is attaching.
Signed-off-by: NSean Stewart <Sean.Stewart@netapp.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

When the scsi_dh_alua handler issues an RTPG during initialization, if it gets
0x06/0x29/0x04 as the sense, it will fail to attach the handler.  NetApp
E-Series returns 0x29/0x00 for power on, and 0x29/0x04 for conditions that
cause the controller to reboot again.  These conditions should be treated
identically within the handler.
Signed-off-by: NSean Stewart <Sean.Stewart@netapp.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Resending with requested rewording of the parameter description.  Currently
ALUA device handler sends STPG command during failover and failback.  Failover
can be optimized by implicit failover (by not to sending STPG command), when 1
is passed as hwhandler parameter in multipath.conf. ex "2 alua 1". We may need
to pass the parameter through module param for alua device handler to optimize
failover if incase retain_attached_hwhandler set in multipath.conf and
hwhandler is set with non-tpgs device handler ex: '1 rdac'.

[jejb: fix up whitespace and other issues]
Signed-off-by: NVijay Chauhan <vijay.chauhan@netapp.com>
Signed-off-by: NSean Stewart <Sean.Stewart@netapp.com>
Acked-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

For the stpg_endio path we are not evaluating the sense. The bug
is that

1. The error value is set to -EIO when there is sense, so we hit the first
error check and always return SCSI_DH_IO.

2. h->senselen is set to zero in submit_stpg. It is not later set to
req->sense_len like in the synchrounous exection paths, so we must
check the req->sense_len field.
Signed-off-by: NMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

A quote from SPC-4: "While in the unavailable primary target port
asymmetric access state, the device server shall support those of
the following commands that it supports while in the active/optimized
state: [ ... ] d) SET TARGET PORT GROUPS; [ ... ]". Hence enable
sending STPG to a target port group that is in the unavailable state.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Acked-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

A quote from SPC-4: "While in the unavailable primary target port
asymmetric access state, the device server shall support those of
the following commands that it supports while in the active/optimized
state: [ ... ] d) SET TARGET PORT GROUPS; [ ... ]". Hence re-enable
sending STPG to a target port group that is in the unavailable state.
Signed-off-by: NBart Van Assche <bvanassche@acm.org>
Reviewed-by: Babu Moger <babu.moger@netapp.com> 
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Currently the backoff algorithm for when to retry alua rtpg
requests progresses geometrically as so:

2, 4, 8, 16, 32, 64... seconds.

This progression can lead to un-needed delay in retrying
alua rtpg requests when the rtpgs are delayed.  A less
aggressive backoff algorithm that is additive would not
lead to such large jumps when delays start getting long, but
would backoff linearly:

2, 4, 6, 8, 10... seconds.
Signed-off-by: NMartin George <marting@netapp.com>
Signed-off-by: NRob Evers <revers@redhat.com>
Reviewed-by: NBabu Moger <babu.moger@netapp.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Some storage arrays are known to return 'illegal request'
when an rtpg extended header request is made.  T10 says the
array should ignore the bit, and return the non-extended
rtpg as the array doesn't support the request.  Working
around this by retrying the rtpg request without the extended
header bit set when the extended rtpg request results in
illegal request.
Signed-off-by: NRob Evers <revers@redhat.com>
Reviewed-by: NBabu Moger <babu.moger@netapp.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

During alua transitions, an array can return transitioning
status in response to rtpg requests.  These requests get
retried for a maximum of 60 seconds by default before timing
out.  Sometimes this timeout isn't sufficient to allow the
array to complete the transition.  T10-spc4 addresses this
under 'Report Target Port Groups' command.

This update retrieves the timeout value from the storage
array if available and retries the transitioning rtpgs
for up to the 'implied transitioning timeout' value
Signed-off-by: NRob Evers <revers@redhat.com>
Reviewed-by: NBabu Moger <babu.moger@netapp.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

This patch optimizes the set target port group(STPG) command. During our
testing, we found that it is not optimal to send stpg command every time
the path group switch happens. This patch uses PREF (preferred target port)
bit with combination of flags passed by multipath user level tool to
optimize this behaviour. If PREF bit is set then it issues a STPG command,
otherwise it will let implicit transfer take place.

By default there is no change in the behaviour. User tool needs to pass the
parameter to make this change take effect. Patch has been tested on NetApp
E series storage.
Signed-off-by: NBabu Moger <babu.moger@netapp.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>