If the initialization of storvsc fails, the storvsc_device_destroy()
causes NULL pointer dereference.

storvsc_bus_scan()
  scsi_scan_target()
    __scsi_scan_target()
      scsi_probe_and_add_lun(hostdata=NULL)
        scsi_alloc_sdev(hostdata=NULL)

	  sdev->hostdata = hostdata

	  now the host allocation fails

          __scsi_remove_device(sdev)

	  calls sdev->host->hostt->slave_destroy() ==
	  storvsc_device_destroy(sdev)
	    access of sdev->hostdata->request_mempool
Signed-off-by: NAles Novak <alnovak@suse.cz>
Signed-off-by: NThomas Abraham <tabraham@suse.com>
Reviewed-by: NJiri Kosina <jkosina@suse.cz>
Acked-by: NK. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Some host adapters do not pass commands through to the target disk
directly. Instead they provide an emulated target which may or may not
accurately report its capabilities. In some cases the physical device
characteristics are reported even when the host adapter is processing
commands on the device's behalf. This can lead to adapter firmware hangs
or excessive I/O errors.

This patch disables WRITE SAME for devices connected to host adapters
that provide an emulated target. Driver writers can disable WRITE SAME
by setting the no_write_same flag in the host adapter template.

[jejb: fix up rejections due to eh_deadline patch]
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>
Cc: stable@kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Remove HV_DRV_VERSION, it has no meaning for upstream drivers.

Initially it was supposed to show the "Linux Integration Services"
version, now it is not in sync anymore with the out-of-tree drivers
available from the MSFT website.

The only place where a version string is still required is the KVP
command "IntegrationServicesVersion" which is handled by
tools/hv/hv_kvp_daemon.c. To satisfy such KVP request from the host pass
the current string to the daemon during KVP userland registration.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Acked-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Increase the value of STORVSC_MAX_IO_REQUESTS to 200 requests. The current
ringbuffer size can support this higher value.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The standard scsi timeout is not appropriate in some of the environments where
Hyper-V is deployed. Set this timeout appropriately for all devices managed
by this driver.

On cloud environments where storage latencies may be unbounded, having the
scsi layer initiating recovery can be problematic since (a) the host is
already implementing a variety of recovery strategies and (b) implementing a
recovery strategy at the VM level may be more appropriate in cases where
storage latencies exceed a certain threshold.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Handle LUN size changes by re-scanning the device.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

In preparation for handling additional sense codes, restructure and cleanup
the error handling code in the command completion code path.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Set scsi_device->no_write_same because the host does not support it.
Also blacklist WRITE_SAME to avoid (and log) accident usage.

If the guest uses the ext4 filesystem, storvsc hangs while it prints
these messages in an endless loop:
...
[  161.459523] hv_storvsc vmbus_0_1: cmd 0x41 scsi status 0x2 srb status 0x6
[  161.462157] sd 2:0:0:0: [sda]
[  161.463135] Sense Key : No Sense [current]
[  161.464983] sd 2:0:0:0: [sda]
[  161.465899] Add. Sense: No additional sense information
[  161.468211] hv_storvsc vmbus_0_1: cmd 0x41 scsi status 0x2 srb status 0x6
[  161.475766] sd 2:0:0:0: [sda]
[  161.476728] Sense Key : No Sense [current]
[  161.478284] sd 2:0:0:0: [sda]
[  161.479441] Add. Sense: No additional sense information
...

This happens with a guest running on Windows Server 2012, but happens to
work while running on Windows Server 2008. WRITE_SAME isnt really
supported by both versions, so disable the command usage globally.
Signed-off-by: NOlaf Hering <olaf@aepfle.de>
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Properly initialize scatterlist before using it.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Use the consolidated GUID definitions in the Hyper-V storage driver.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Properly account for I/O in transit before returning from the RESET call.
In the absense of this patch, we could have a situation where the host may
respond to a command that was issued prior to the issuance of the RESET
command at some arbitrary time after responding to the RESET command.
Currently, the host does not do anything with the RESET command.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Cc: stable@vger.kernel.org
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

Hyper-V cannot process some commands like ATA_12 and ATA_16. It also returns a
very generic error when this happens (SRB_STATUS_ERROR).  Most of the time we
treat SRB_STATUS_ERROR as DID_TARGET_FAILURE which causes error handler retry,
but in the case of pass through commands, they'll never succeed (and the error
handler will offline the device), so put a discriminating block in the command
completion routing and send the SRB_STATUS_ERROR upwards with DID_PASSTHROUGH
for commands we know should not be retried.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NJames Bottomley <JBottomley@Parallels.com>

The storage driver (storvsc_drv.c) handles all block storage devices
assigned to Linux guests hosted on Hyper-V. This driver has been in the
staging tree for a while and this patch moves it out of the staging area.

James was willing to apply this patch during the 3.3-rc phase and a decision
was taken to defer this to 3.4 since Greg had queued up a bunch of storvsc
patches for 3.4. Now that Greg has applied all of the pending storvsc patches,
I am sending this patch to move this driver out of staging. Based on James'
recommendation, this patch gets rid of the unneeded files in the staging/hv
directory.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Acked-by: NJames Bottomley <JBottomley@Parallels.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Consolidate all definitions that support communication with the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Consolidate the request structure by getting rid of struct hv_storvsc_request.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Get rid of some unused defines.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Cleanup some protocol related constants.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Cleanup the code for generating protocol version.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Miscellaneous cleanup of storvsc driver - get rid of unnecessary defines and
use fixed size types for structures used for communication with the host.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename the context field in hv_storvsc_request. As part of this change
fix the type of this field.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Get rid of the on_io_completion field  in struct hv_storvsc_request. As part of this
relocate the bounce buffer handling code (to avoid having forward declarations).
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a comment to explain life-cycle management and fix format issue.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Relocate the storvsc_remove() function to a different location in the file
and invoke scsi_host_put() only after all the cleanup.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Cleanup storvsc_host_reset_handler() by getting rid of storvsc_host_reset().
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce defines for srb status codes.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Cleanup storvsc_queuecommand(). As part of this cleanup, rename the function to
check if the scsi command can be sent to the host, consolidate error recovery
and get rid of some dead code.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Cleanup storvsc_probe(). As part of this cleanup, get rid of
storvsc_get_ide_info() by inlining the necessary code.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use consistent format for comments and get rid of some unnecessary
comments.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Set the length field of the scatter gather elements correctly when we create
the bounce buffer. When we use the bounce buffer for a "write" operation,
the act of copying to the bounce buffer, correctly deals with this issue.
However, on the "read" side, the current code was not correctly setting
the buffer length. Fix this bug. Note that when we copy from the bounce
buffer (for the read case), the amount we copy is controlled by the original
scatter gather list given to the driver.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Reported-by: NDadok Milan <dadok@kvados.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The current code implemented a per-HBA memory pool mechanism. For IDE disks
managed by this driver, there is a one to one correspondance between the
block device and the associated virtual HBA and since currently only IDE devices
can be the boot device, this addressed the deadlock issues that were raised during
the review process. This patch implements a per-lun memory pool mechanism.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix a bug in copy_from_bounce_buffer().
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fix a bug in storvsc_command_completion() that leaks memory when scatter/gather
lists are used on the "write" side.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The code in storvsc_device_alloc() is not needed as this would be
done by default. Get rid of it. We still keep the function as we use
this hook to allocate per-LUN memory pools in a later patch.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Disable clustering, since the host side on Hyper-V requires that
each I/O element not exceed the page size. As part of this
cleanup, get rid of the function to merge bvecs, as the primary
reason for this function was to avoid having an element exceed
the page size.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Support hot-removing of scsi devices.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Support hot add of scsi disks.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

In preparation for supporting hot add/remove of scsi devices,
upgrade the vmstor protocol version.
Signed-off-by: NK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: NHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>