In preparation for adding new states (SAS_HA_DRAINING, SAS_HA_FROZEN),
convert ha->state into a set of flags.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
The locks only served to make sure the pending event bitmask was updated
consistently.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Arrange for the deallocation of a struct domain_device object when it no
longer has:
1/ any children
2/ references by any scsi_targets
3/ references by a lldd
The comment about domain_device lifetime in
Documentation/scsi/libsas.txt is stale as it appears mainline never had
a version of a struct domain_device that was registered as a kobject.
We now manage domain_device reference counts on behalf of external
agents.
Reviewed-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Per commit 3e4ec344 "libata: kill ATA_FLAG_DISABLED" needing to set
ATA_DEV_NONE is a holdover from before libsas converted to the
"new-style" ata-eh.
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Commit 1e34c838 "[SCSI] libsas: remove spurious sata control register
read/write" removed the routines to fake the presence of the sata
control registers, now remove the unused data structure fields to kill
any remaining confusion.
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
port->dev_list maintains a list of devices attached to a given sas root port.
It needs to be mutated under a lock as contexts outside of the
single-threaded-libsas-workqueue access the list via sas_find_dev_by_rphy().
Fixup locations where the list was being mutated without a lock.
This is a follow-up to commit 5911e963 "[SCSI] libsas: remove expander
from dev list on error", where Luben noted [1]:
> 2/ We have unlocked list manipulations in sas_ex_discover_end_dev(),
> sas_unregister_common_dev(), and sas_ex_discover_end_dev()
Yes, I can see that and that is very unfortunate.
[1]: http://marc.info/?l=linux-scsi&m=131480962006471&w=2
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Based on original implementation from Jiangbi Liu and Maciej Trela.
ATAPI transfers happen in two-to-three stages. The two stage atapi
commands are those that include a dma data transfer. The data transfer
portion of these operations is handled by the hardware packet-dma
acceleration. The three-stage commands do not have a data transfer and
are handled without hardware assistance in raw frame mode.
stage1: transmit host-to-device fis to notify the device of an incoming
atapi cdb. Upon reception of the pio-setup-fis repost the task_context
to perform the dma transfer of the cdb+data (go to stage3), or repost
the task_context to transmit the cdb as a raw frame (go to stage 2).
stage2: wait for hardware notification of the cdb transmission and then
go to stage 3.
stage3: wait for the arrival of the terminating device-to-host fis and
terminate the command.
To keep the implementation simple we only support ATAPI packet-dma
protocol (for commands with data) to avoid needing to handle the data
transfer manually (like we do for SATA-PIO). This may affect
compatibility for a small number of devices (see
ATA_HORKAGE_ATAPI_MOD16_DMA).
If the data-transfer underruns, or encounters an error the
device-to-host fis is expected to arrive in the unsolicited frame queue
to pass to libata for disposition. However, in the DONE_UNEXP_FIS (data
underrun) case it appears we need to craft a response. In the
DONE_REG_ERR case we do receive the UF and propagate it to libsas.
Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
If the user has disabled CONFIG_SCSI_SAS_HOST_SMP then libsas drivers
will not be receiving smp-gpio frames and do not need this lookup code.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Tested-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Allow expander table-to-table attachments for
expanders that support it.
Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Add SFF-8485 v0.7 / SAS-1 smp-write-gpio register support to libsas.
Defer SAS-2 support unless/until it defines an sgpio interface.
Minimum implementation needed to get the lights blinking.
try_test_sas_gpio_gp_bit() provides a common method to parse the
incoming write data (raw bitstream), and the to_sas_gpio_gp_bit() helper
routine can be used as a basis for the set/clear operations for the
'read' implementation. Host implementations parse as many bits
(ODx.[012]) as are locally supported and report the number of registers
successfully written. If the submitted data overruns the internal
number of registers available report the write as a success with the
number of bytes remaining reported in ->resid_len.
Example (assuming an active backplane) set the "identify" pattern for
the first 21 devices:
smp_write_gpio --count=2 --data=92,49,24,92,24,92,49,24 -t 4 --index=1 /dev/bsg/sas_hostX
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Now that isci has added a 3rd open coded user of this functionality just
share the libsas version.
Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This allows a libsas driver to optionally provide a soft reset handler
for libata to drive. The isci driver allows software to control the
assertion/deassertion of SRST.
[jejb: checkpatch.pl fixes]
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <jbottomley@parallels.com>
To date libsas has only looked at the attached sas address when
determining the formation of wide ports. The specification and some
hardware expects that phys with different addresses will not form a wide
port unless the local peer phys also match each other. Introduce a flag
to select stricter behavior at sas_register_ha() time. The flag can be
dropped once it is known that all libsas users expect the same behavior.
Current drivers just initialize this field to zero and get the
traditional behavior.
Reported-by: Patrick Thomson <patrick.s.thomson@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Move the mid-layer's ->queuecommand() invocation from being locked
with the host lock to being unlocked to facilitate speeding up the
critical path for drivers who don't need this lock taken anyway.
The patch below presents a simple SCSI host lock push-down as an
equivalent transformation. No locking or other behavior should change
with this patch. All existing bugs and locking orders are preserved.
Additionally, add one parameter to queuecommand,
struct Scsi_Host *
and remove one parameter from queuecommand,
void (*done)(struct scsi_cmnd *)
Scsi_Host* is a convenient pointer that most host drivers need anyway,
and 'done' is redundant to struct scsi_cmnd->scsi_done.
Minimal code disturbance was attempted with this change. Most drivers
needed only two one-line modifications for their host lock push-down.
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
Acked-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sd will get hung up issuing commands to flush write cache if a SAS
device behind the expander is unplugged without warning. Change libsas
to reject commands to domain devices that have already gone away.
[maciej.trela@intel.com: removed setting ->gone in sas_deform_port() to
permit sync cache commands at module removal]
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Tested-by: Haipao Fan <haipao.fan@intel.com>
Signed-off-by: Maciej Trela <maciej.trela@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
We have two separate definitions for identical constants with nearly the
same name. One comes from the generic headers in scsi.h; the other is
an enum in libsas.h ... it's causing confusion about which one is
correct (fortunately they both are).
Fix this by eliminating the libsas.h duplicate
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
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: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
This patch modifies scsi_host_template->change_queue_depth so that
it takes an argument indicating why it is being called. This will be
used so that if a LLD needs to do some extra processing when
handling queue fulls or later ramp ups, it can do so.
This is a simple port of the drivers setting a change_queue_depth
callback. In the patch I just have these LLDs adjust the queue depth
if the user was requesting it.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
[Vasu.Dev: v2
Also converted pmcraid_change_queue_depth and then verified
all modules compile using "make allmodconfig" for any new build
warnings on X86_64.
Updated original description after combing two original
patches from Mike to make this patch git bisectable.]
Signed-off-by: Vasu Dev <vasu.dev@intel.com>
[jejb: fixed up 53c700]
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they (or some user of them) rely
on it dragging in some unrelated header file, but I can't build all
these files, so we'll have to fix any build failures as they come up.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Provide a facility to use the request_firmware() interface to get a SAS
address from userspace. This can be used by SAS LLDDs that cannot
obtain the address from the host adapter.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This is needed by the to be added I_T reset function in aic94xx. It
needs to know the local phy so it can send a link or hard reset along
the path.
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Break out the frame processor for STP tasks from aic94xx so they can
be shared by other SAS HBA's
Original patch from Jeff Garzik <jeff@garzik.org>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
This is bad for two reasons:
1. If they're returned to outside applications, no-one knows what
they mean.
2. Eventually they'll clash with the ever expanding standard error
codes.
The problem error code in question is ETASK. I've replaced this by
ECOMM (communications error on send) a network error code that seems to
most closely relay what ETASK meant.
Acked-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Annotate sas_queuecommand with locking details, and clean up a few
more sparse warnings about static/non-static declarations.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
sparse complains about the mixing of enums in libsas. Since the
underlying numeric values of both enums are the same, combine them
to get rid of the warning.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Not architecture specific code should not #include <asm/scatterlist.h>.
This patch therefore either replaces them with
#include <linux/scatterlist.h> or simply removes them if they were
unused.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Eliminate unnecessary PCI dependencies in libsas. It should use generic
DMA and struct device like other subsystems.
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This patch adds support for SAS Management Protocol (SMP) passthrough
support via bsg. aic94xx can use this.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This is a respin of my earlier patch that migrates the ATA support code
into a separate file. For now, the controversial linking bits have
been removed per James Bottomley's request for a patch that contains
only the migration diffs, which means that libsas continues to require
libata. I intend to address that problem in a separate patch.
This patch is against the aic94xx-sas-2.6 git tree, and it has been
sanity tested on my x206m with Seagate SATA and SAS disks without
uncovering any new problems.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Hook the scsi_host_template functions in libsas to delegate
functionality to libata when appropriate.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Misc code changes and merge fixes and update for libata->drivers/ata
move
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
* master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6: (97 commits)
[SCSI] zfcp: removed wrong comment
[SCSI] zfcp: use of uninitialized variable
[SCSI] zfcp: Invalid locking order
[SCSI] aic79xx: use dma_get_required_mask()
[SCSI] aic79xx: fix bracket mismatch in unused macro
[SCSI] BusLogic: Replace 'boolean' by 'bool'
[SCSI] advansys: clean up warnings
[SCSI] 53c7xx: brackets fix in uncompiled code
[SCSI] nsp_cs: remove old scsi code
[SCSI] aic79xx: make ahd_match_scb() static
[SCSI] DAC960: kmalloc->kzalloc/Casting cleanups
[SCSI] scsi_kmap_atomic_sg(): check that local irqs are disabled
[SCSI] Buslogic: local_irq_disable() is redundant after local_irq_save()
[SCSI] aic94xx: update for v28 firmware
[SCSI] scsi_error: Fix lost EH commands
[SCSI] aic94xx: Add default bus reset handler
[SCSI] aic94xx: Remove TMF result code munging
[SCSI] libsas: Add an LU reset mechanism to the error handler
[SCSI] libsas: Don't BUG when connecting two expanders via wide port
[SCSI] st: fix Tape dies if wrong block size used, bug 7919
...
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After discussion with andmike and dougg, it seems that the purpose of
eh_device_reset_handler is to issue LU resets, and that
eh_bus_reset_handler would be a more appropriate place for a phy reset.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This patch moves the code that handles SAS failures out of the main EH
function and into a separate function. It also detects commands that have
no sas_task (i.e. they completed, but with error data) and sends them into
scsi_error for processing. This allows us to handle SCSI errors (and
enables auto-spinup as a side effect) instead of dropping them on the
floor and falling into an infinite loop. It also requires the
implementation of a device reset function, which the SAS failure code has
been modified to employ for REQ_DEVICE_RESET.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Track sas_ha_struct state so that we ignore events that come in while
we're shutting things down.
Signed-off-by: Malahal Naineni <malahal@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
sas_task_abort() should simply abort the upper-level SCSI command and wait
until the error handler to send the actual ABORT TASK command. By
deferring things to the EH we simplify the concurrency coordination and
eliminate some race conditions. Note that sas_task_abort has a few hooks
to handle libsas internal commands properly too.
Also rename do_sas_task_abort to __sas_task_abort just in case we really
want to abort the task *right now* and we don't have a scsi_cmnd attached
to the command. This is a hook for libata internal commands to abort.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
When a SAS LLDD needs to request a device port reset, it needs to have all
commands aborted before it can reset the port. Since commands are put on
the EH's list in the order that they were queued, the LLDD can set a "need
reset" flag in the last task to be aborted so that the EH can reset the
port after all commands are aborted.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This flag is no longer necessary because we push tasks to be aborted into
the EH as soon as we possibly can, and let the SCSI EH code take care of
the coordination for which this flag was used.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This patch lets a user arbitrarily enable or disable a phy via sysfs.
Potential applications include shutting down a phy to replace one
lane of wide port, and (more importantly) providing a method for the
libata SATL to control the phy.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
On a system with many SAS targets, it appears possible that a scsi_cmnd
can time out without ever making it to the SAS LLDD or at the same time
that a completion is occurring. In both of these cases, telling the
LLDD to abort the sas_task makes no sense because the LLDD won't know
about the sas_task; what we really want to do is to increase the timer.
Note that this involves creating another sas_task bit to indicate
whether or not the task has been sent to the LLDD; I could have
implemented this by slightly redefining SAS_TASK_STATE_PENDING, but
this way seems cleaner.
This second version amends the aic94xx portion to set the
TASK_AT_INITIATOR flag for all sas_tasks that were passed to
lldd_execute_task.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Replace all uses of kmem_cache_t with struct kmem_cache.
The patch was generated using the following script:
#!/bin/sh
#
# Replace one string by another in all the kernel sources.
#
set -e
for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do
quilt add $file
sed -e "1,\$s/$1/$2/g" $file >/tmp/$$
mv /tmp/$$ $file
quilt refresh
done
The script was run like this
sh replace kmem_cache_t "struct kmem_cache"
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Conflicts:
drivers/pcmcia/ds.c
Fix up merge failures with Linus's head and fix new compile failures.
Signed-Off-By: David Howells <dhowells@redhat.com>
Conflicts:
drivers/infiniband/core/iwcm.c
drivers/net/chelsio/cxgb2.c
drivers/net/wireless/bcm43xx/bcm43xx_main.c
drivers/net/wireless/prism54/islpci_eth.c
drivers/usb/core/hub.h
drivers/usb/input/hid-core.c
net/core/netpoll.c
Fix up merge failures with Linus's head and fix new compilation failures.
Signed-Off-By: David Howells <dhowells@redhat.com>
include/scsi/libsas.h:479: error: field 'smp_req' has incomplete type
include/scsi/libsas.h:480: error: field 'smp_resp' has incomplete type
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch implements a REQ_DEVICE_RESET handler for the aic94xx
driver. Like the earlier REQ_TASK_ABORT patch, this patch defers the
device reset to the Scsi_Host's workqueue, which has the added benefit
of ensuring that the device reset does not happen at the same time
that the abort tmfs are being processed. After the phy reset, the
busted drive should go away and be re-detected later, which is indeed
what I've seen on both a x260 and a x206m.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This patch adds an external function, sas_abort_task, to enable LLDDs
to abort sas_tasks. It also adds a work_struct so that the actual
work of aborting a task can be shifted from tasklet context (in the
LLDD) onto the scsi_host's workqueue.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>