On the interrupt path, we repeatedly establish the pointer to the
storvsc_device. While the compiler does inline get_in_stor_device() (and
other static functions) in the call chain in the interrupt path, the
compiler is repeatedly inlining the call to get_in_stor_device() each
time it is invoked.  The return value of get_in_stor_device() can be
cached in the interrupt path since there is higher level serialization
in place to ensure correct handling when the module unload races with
the processing of an incoming message from the host.  Optimize this code
path by caching the pointer to storvsc_device and passing it as an
argument.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The function storvsc_channel_init() repeatedly interacts with the host
to extract various channel properties. Refactor this code to eliminate
code repetition.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

For FC devices managed by this driver, atttach the appropriate transport
template. This will allow us to create the appropriate sysfs files for
these devices. With this we can publish the wwn for both the port and the node.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The hv_fc_wwn_packet is exchanged over vmbus. Make the definition in
Linux match the Windows definition.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NLong Li <longli@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Introduce a logging level for storvsc to log certain error/warning
messages. Those messages are helpful in some environments,
e.g. Microsoft Azure, for customer support and troubleshooting purposes.
Signed-off-by: NLong Li <longli@microsoft.com>
Acked-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

SRB status can have additional information. Mask these out before processing
SRB status.

This patch was sent as part of a collection of patches more than a year ago.
While the rest of the patches in the set were comitted, this patch was not.
I woulod like to thank Olaf for noticing that this patch was not committed
upstream.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Storvsc driver needs to ensure there are no 'holes' in the presented
sg list (all segments in the middle of the list need to be of PAGE_SIZE).
When a hole is detected storvsc driver creates a 'bounce sgl' without
holes and copies data over with copy_{to,from}_bounce_buffer() functions.
Setting virt_boundary_mask to PAGE_SIZE - 1 guarantees we'll never see
such holes so we can significantly simplify the driver. This is also
supposed to bring us some performance improvement for certain workloads
as we eliminate copying.
Reported-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NK. Y. Srinivasan <kys@microsoft.com>
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Don't set the SRB_FLAGS_QUEUE_ACTION_ENABLE flag since we are not specifying
tags.  Without this, the qlogic driver doesn't work properly with storvsc.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

In the function storvsc_channel_init(), error code was not getting
set correctly in some of the failure cases. Fix this issue.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Allow WRITE_SAME for Windows10 and above hosts.
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Use storage protocol version instead of vmbus protocol
version when determining storage capabilities.
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Use correct defaults for values determined by protocol negotiation,
instead of resetting them with every scsi controller.
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Currently we are making decisions based on vmbus protocol versions
that have been negotiated; use storage potocol versions instead.

[jejb: fold ARRAY_SIZE conversion suggested by Johannes Thumshirn
<jthumshirn@suse.de>
make vmstor_protocol static]
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Use a single value to track protocol versions to simplify
comparisons and to be consistent with vmbus version tracking.
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Rather than look for sets of specific protocol versions,
make decisions based on ranges. This will be safer and require fewer changes
going forward as we add more storage protocol versions.
Tested-by: NAlex Ng <alexng@microsoft.com>
Signed-off-by: NKeith Mange <keith.mange@microsoft.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Comment in struct Scsi_Host says that drivers are not supposed to access
__devices directly. storvsc_host_scan() doesn't happen in irq context
so we can just use shost_for_each_device().
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Acked-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Under the 'default' case in scmnd->sc_data_direction we have 3 options:
- DMA_NONE which we handle correctly.
- DMA_BIDIRECTIONAL which is never supposed to be set by SCSI stack.
- Garbage value.

Do WARN() and return -EINVAL in the last two cases. virtio_scsi does
BUG_ON() here but it looks like an overkill.
Reported-by: NRadim Krčmář <rkrcmar@redhat.com>
Signed-off-by: NVitaly Kuznetsov <vkuznets@redhat.com>
Acked-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Set the SRB flags correctly when there is no data transfer.  Without this
change some IHV drivers will fail valid commands such as TEST_UNIT_READY.

Cc: <stable@vger.kernel.org>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Set the tablesize based on the information given by the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Tested-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

The current code assumes that the scatterlists presented are not chained.
Fix the code to not make this assumption.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

We may exit this function without properly freeing up the maapings
we may have acquired. Fix the bug.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

The storage protocol informs the guest of the I/O capabilities of the storage
stack. Retrieve this information and use it in the guest.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

The current code always sent packets without data on the primary channel.
Properly distribute sending of packets with no data amongst all available
channels. I would like to thank Long Li for noticing this problem.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Size the queue depth based on the ringbuffer size. Also accommodate for the
fact that we could have multiple channels (ringbuffers) per adaptor.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

Increase the default ring buffer size as this can significantly
improve performance especially on high latency storage back-ends.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Odin.com>

On win8 and win8 r2 hosts force SPC-3 compliance for MSFT virtual disks.
Ubuntu has been carrying a similar patch outside the tree for a while now.
Starting with win10, the host will support SPC-3 compliance. Based on all
the testing that has been done on win8 and win8 r2 hosts, we are comfortable
claiming SPC-3 compliance on these hosts as well. This will enable TRIM
support on these hosts.

Suggested by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Commit 4cd83ecd changed the limits to
reflect the values on the host. It turns out that WS2008R2 cannot
correctly handle these new limits. Fix this bug by setting the limits
based on the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The host asks the guest to scan when a LUN is removed or added.
The only way a guest can identify the removed LUN is when an I/O is
attempted on a removed LUN - the SRB status code indicates that the LUN
is invalid. We currently handle this SRB status and remove the device.

Rather than waiting for an I/O to remove the device, force the discovery of
LUNs that may have been removed prior to discovering LUNs that may have
been added.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The virtual HBA that storvsc implements can support multiple channels and
targets. So, scan the host when the host notifies that a scan is needed.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

STORVSC uses its own momory pool to manage device request data.  However,
the SCSI layer already has a mechanisim for allocating additional memory
for each command issued to device driver. This patch removes the memory
pool in STORVSC and makes it use SCSI layer to allocate memory for device
request data.
Reviewed-by: NLong Li <longli@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

When ring buffer returns an error indicating retry, storvsc may not
return a proper error code to SCSI when bounce buffer is not used.
This has introduced I/O freeze on RAID running atop storvsc devices.
This patch fixes it by always returning a proper error code.
Signed-off-by: NLong Li <longli@microsoft.com>
Reviewed-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
cc: stable@vger.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>

Remove the tagged argument from scsi_adjust_queue_depth, and just let it
handle the queue depth.  For most drivers those two are fairly separate,
given that most modern drivers don't care about the SCSI "tagged" status
of a command at all, and many old drivers allow queuing of multiple
untagged commands in the driver.

Instead we start out with the ->simple_tags flag set before calling
->slave_configure, which is how all drivers actually looking at
->simple_tags except for one worke anyway.  The one other case looks
broken, but I've kept the behavior as-is for now.

Except for that we only change ->simple_tags from the ->change_queue_type,
and when rejecting a tag message in a single driver, so keeping this
churn out of scsi_adjust_queue_depth is a clear win.

Now that the usage of scsi_adjust_queue_depth is more obvious we can
also remove all the trivial instances in ->slave_alloc or ->slave_configure
that just set it to the cmd_per_lun default.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NMike Christie <michaelc@cs.wisc.edu>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NMartin K. Petersen <martin.petersen@oracle.com>

We should be using the standard dev_printk() variants for
sense code printing.

[hch: remove __scsi_print_sense call in xen-scsiback, Acked by Juergen]
[hch: folded bracing fix from Dan Carpenter]
Signed-off-by: NHannes Reinecke <hare@suse.de>
Reviewed-by: NRobert Elliott <elliott@hp.com>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Get rid of the warning messages since they will clutter up various system logs
and are of questionable value to the end user. For debugging purposes, this
information can be gotten by setting the scsi log level appropriately.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Add blist flags to permit the reading of the VPD pages even when
the target may claim SPC-2 compliance. MSFT targets currently
claim SPC-2 compliance while they implement post SPC-2 features.
With this patch we can correctly handle WRITE_SAME_16 issues.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

On some Windows hosts on FC SANs, TEST_UNIT_READY can return SRB_STATUS_ERROR.
Correctly handle this. Note that there is sufficient sense information to
support scsi error handling even in this case.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Correctly set SRB flags for all valid I/O directions. Some IHV drivers on the
Windows host require this. The host validates the command and SRB flags
prior to passing the command down to native driver stack.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

On Azure, we have seen instances of unbounded I/O latencies. To deal with
this issue, implement handler that can reset the timeout. Note that the
host gaurantees that it will respond to each command that has been issued.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
[hch: added a better comment explaining the issue]
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Based on the negotiated VMBUS protocol version, we adjust the size of the storage
protocol messages. The two sizes we currently handle are pre-win8 and post-win8.
In WS2012 R2, we are negotiating higher VMBUS protocol version than the win8
version. Make adjustments to correctly handle this.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHannes Reinecke <hare@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>