<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/target/target_core_device.c, branch linux-3.12.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>target: Fix virtual LUN=0 target_configure_device failure OOPs</title>
<updated>2015-04-09T11:14:19+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2015-03-05T03:28:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=033acbf6a597707356691d0621c1496bc5a610b1'/>
<id>033acbf6a597707356691d0621c1496bc5a610b1</id>
<content type='text'>
commit 5f7da044f8bc1cfb21c962edf34bd5699a76e7ae upstream.

This patch fixes a NULL pointer dereference triggered by a late
target_configure_device() -&gt; alloc_workqueue() failure that results
in target_free_device() being called with DF_CONFIGURED already set,
which subsequently OOPses in destroy_workqueue() code.

Currently this only happens at modprobe target_core_mod time when
core_dev_setup_virtual_lun0() -&gt; target_configure_device() fails,
and the explicit target_free_device() gets called.

To address this bug originally introduced by commit 0fd97ccf45, go
ahead and move DF_CONFIGURED to end of target_configure_device()
code to handle this special failure case.

Reported-by: Claudio Fleiner &lt;cmf@daterainc.com&gt;
Cc: Claudio Fleiner &lt;cmf@daterainc.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5f7da044f8bc1cfb21c962edf34bd5699a76e7ae upstream.

This patch fixes a NULL pointer dereference triggered by a late
target_configure_device() -&gt; alloc_workqueue() failure that results
in target_free_device() being called with DF_CONFIGURED already set,
which subsequently OOPses in destroy_workqueue() code.

Currently this only happens at modprobe target_core_mod time when
core_dev_setup_virtual_lun0() -&gt; target_configure_device() fails,
and the explicit target_free_device() gets called.

To address this bug originally introduced by commit 0fd97ccf45, go
ahead and move DF_CONFIGURED to end of target_configure_device()
code to handle this special failure case.

Reported-by: Claudio Fleiner &lt;cmf@daterainc.com&gt;
Cc: Claudio Fleiner &lt;cmf@daterainc.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Drop arbitrary maximum I/O size limit</title>
<updated>2015-02-02T18:13:57+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2015-01-30T22:17:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d99060df01b027501e55b8ce92c072aa60f87ee3'/>
<id>d99060df01b027501e55b8ce92c072aa60f87ee3</id>
<content type='text'>
commit 046ba64285a4389ae5e9a7dfa253c6bff3d7c341 upstream.

This patch drops the arbitrary maximum I/O size limit in sbc_parse_cdb(),
which currently for fabric_max_sectors is hardcoded to 8192 (4 MB for 512
byte sector devices), and for hw_max_sectors is a backend driver dependent
value.

This limit is problematic because Linux initiators have only recently
started to honor block limits MAXIMUM TRANSFER LENGTH, and other non-Linux
based initiators (eg: MSFT Fibre Channel) can also generate I/Os larger
than 4 MB in size.

Currently when this happens, the following message will appear on the
target resulting in I/Os being returned with non recoverable status:

  SCSI OP 28h with too big sectors 16384 exceeds fabric_max_sectors: 8192

Instead, drop both [fabric,hw]_max_sector checks in sbc_parse_cdb(),
and convert the existing hw_max_sectors into a purely informational
attribute used to represent the granuality that backend driver and/or
subsystem code is splitting I/Os upon.

Also, update FILEIO with an explicit FD_MAX_BYTES check in fd_execute_rw()
to deal with the one special iovec limitiation case.

v2 changes:
  - Drop hw_max_sectors check in sbc_parse_cdb()

Reported-by: Lance Gropper &lt;lance.gropper@qosserver.com&gt;
Reported-by: Stefan Priebe &lt;s.priebe@profihost.ag&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 046ba64285a4389ae5e9a7dfa253c6bff3d7c341 upstream.

This patch drops the arbitrary maximum I/O size limit in sbc_parse_cdb(),
which currently for fabric_max_sectors is hardcoded to 8192 (4 MB for 512
byte sector devices), and for hw_max_sectors is a backend driver dependent
value.

This limit is problematic because Linux initiators have only recently
started to honor block limits MAXIMUM TRANSFER LENGTH, and other non-Linux
based initiators (eg: MSFT Fibre Channel) can also generate I/Os larger
than 4 MB in size.

Currently when this happens, the following message will appear on the
target resulting in I/Os being returned with non recoverable status:

  SCSI OP 28h with too big sectors 16384 exceeds fabric_max_sectors: 8192

Instead, drop both [fabric,hw]_max_sector checks in sbc_parse_cdb(),
and convert the existing hw_max_sectors into a purely informational
attribute used to represent the granuality that backend driver and/or
subsystem code is splitting I/Os upon.

Also, update FILEIO with an explicit FD_MAX_BYTES check in fd_execute_rw()
to deal with the one special iovec limitiation case.

v2 changes:
  - Drop hw_max_sectors check in sbc_parse_cdb()

Reported-by: Lance Gropper &lt;lance.gropper@qosserver.com&gt;
Reported-by: Stefan Priebe &lt;s.priebe@profihost.ag&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Martin K. Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Fix APTPL metadata handling for dynamic MappedLUNs</title>
<updated>2014-11-13T18:02:31+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2014-10-04T04:23:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=8bb710aed647d505da7434ff9c3162344e2ad309'/>
<id>8bb710aed647d505da7434ff9c3162344e2ad309</id>
<content type='text'>
commit e24805637d2d270d7975502e9024d473de86afdb upstream.

This patch fixes a bug in handling of SPC-3 PR Activate Persistence
across Target Power Loss (APTPL) logic where re-creation of state for
MappedLUNs from dynamically generated NodeACLs did not occur during
I_T Nexus establishment.

It adds the missing core_scsi3_check_aptpl_registration() call during
core_tpg_check_initiator_node_acl() -&gt; core_tpg_add_node_to_devs() in
order to replay any pre-loaded APTPL metadata state associated with
the newly connected SCSI Initiator Port.

Cc: Mike Christie &lt;michaelc@cs.wisc.edu&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit e24805637d2d270d7975502e9024d473de86afdb upstream.

This patch fixes a bug in handling of SPC-3 PR Activate Persistence
across Target Power Loss (APTPL) logic where re-creation of state for
MappedLUNs from dynamically generated NodeACLs did not occur during
I_T Nexus establishment.

It adds the missing core_scsi3_check_aptpl_registration() call during
core_tpg_check_initiator_node_acl() -&gt; core_tpg_add_node_to_devs() in
order to replay any pre-loaded APTPL metadata state associated with
the newly connected SCSI Initiator Port.

Cc: Mike Christie &lt;michaelc@cs.wisc.edu&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Fix left-over se_lun-&gt;lun_sep pointer OOPs</title>
<updated>2014-07-17T11:43:14+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2014-06-16T20:25:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=659489c914e8f1c88a453f8b91134dab58cdf8b6'/>
<id>659489c914e8f1c88a453f8b91134dab58cdf8b6</id>
<content type='text'>
commit 83ff42fcce070801a3aa1cd6a3269d7426271a8d upstream.

This patch fixes a left-over se_lun-&gt;lun_sep pointer OOPs when one
of the /sys/kernel/config/target/$FABRIC/$WWPN/$TPGT/lun/$LUN/alua*
attributes is accessed after the $DEVICE symlink has been removed.

To address this bug, go ahead and clear se_lun-&gt;lun_sep memory in
core_dev_unexport(), so that the existing checks for show/store
ALUA attributes in target_core_fabric_configfs.c work as expected.

Reported-by: Sebastian Herbszt &lt;herbszt@gmx.de&gt;
Tested-by: Sebastian Herbszt &lt;herbszt@gmx.de&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 83ff42fcce070801a3aa1cd6a3269d7426271a8d upstream.

This patch fixes a left-over se_lun-&gt;lun_sep pointer OOPs when one
of the /sys/kernel/config/target/$FABRIC/$WWPN/$TPGT/lun/$LUN/alua*
attributes is accessed after the $DEVICE symlink has been removed.

To address this bug, go ahead and clear se_lun-&gt;lun_sep memory in
core_dev_unexport(), so that the existing checks for show/store
ALUA attributes in target_core_fabric_configfs.c work as expected.

Reported-by: Sebastian Herbszt &lt;herbszt@gmx.de&gt;
Tested-by: Sebastian Herbszt &lt;herbszt@gmx.de&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>target: Don't allow setting WC emulation if device doesn't support</title>
<updated>2014-06-09T13:53:45+00:00</updated>
<author>
<name>Andy Grover</name>
<email>agrover@redhat.com</email>
</author>
<published>2014-05-14T22:48:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1b8b4d6d14a3704e221b0e580d93650903ab7038'/>
<id>1b8b4d6d14a3704e221b0e580d93650903ab7038</id>
<content type='text'>
commit 07b8dae38b09bcfede7e726f172e39b5ce8390d9 upstream.

Just like for pSCSI, if the transport sets get_write_cache, then it is
not valid to enable write cache emulation for it. Return an error.

see https://bugzilla.redhat.com/show_bug.cgi?id=1082675

Reviewed-by: Chris Leech &lt;cleech@redhat.com&gt;
Signed-off-by: Andy Grover &lt;agrover@redhat.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 07b8dae38b09bcfede7e726f172e39b5ce8390d9 upstream.

Just like for pSCSI, if the transport sets get_write_cache, then it is
not valid to enable write cache emulation for it. Return an error.

see https://bugzilla.redhat.com/show_bug.cgi?id=1082675

Reviewed-by: Chris Leech &lt;cleech@redhat.com&gt;
Signed-off-by: Andy Grover &lt;agrover@redhat.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Jiri Slaby &lt;jslaby@suse.cz&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target/file: Update hw_max_sectors based on current block_size</title>
<updated>2014-01-09T20:25:09+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2013-12-12T20:24:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cd3f6dea647f4d5e49f44ae919966e18b0e63ac7'/>
<id>cd3f6dea647f4d5e49f44ae919966e18b0e63ac7</id>
<content type='text'>
commit 95cadace8f3959282e76ebf8b382bd0930807d2c upstream.

This patch allows FILEIO to update hw_max_sectors based on the current
max_bytes_per_io.  This is required because vfs_[writev,readv]() can accept
a maximum of 2048 iovecs per call, so the enforced hw_max_sectors really
needs to be calculated based on block_size.

This addresses a &gt;= v3.5 bug where block_size=512 was rejecting &gt; 1M
sized I/O requests, because FD_MAX_SECTORS was hardcoded to 2048 for
the block_size=4096 case.

(v2: Use max_bytes_per_io instead of -&gt;update_hw_max_sectors)

Reported-by: Henrik Goldman &lt;hg@x-formation.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 95cadace8f3959282e76ebf8b382bd0930807d2c upstream.

This patch allows FILEIO to update hw_max_sectors based on the current
max_bytes_per_io.  This is required because vfs_[writev,readv]() can accept
a maximum of 2048 iovecs per call, so the enforced hw_max_sectors really
needs to be calculated based on block_size.

This addresses a &gt;= v3.5 bug where block_size=512 was rejecting &gt; 1M
sized I/O requests, because FD_MAX_SECTORS was hardcoded to 2048 for
the block_size=4096 case.

(v2: Use max_bytes_per_io instead of -&gt;update_hw_max_sectors)

Reported-by: Henrik Goldman &lt;hg@x-formation.com&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>target: Update copyright ownership/year information to 2013</title>
<updated>2013-09-11T03:23:36+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@linux-iscsi.org</email>
</author>
<published>2013-09-05T22:29:12+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4c76251e8e8f704ed7eace603a8041458a1ed16f'/>
<id>4c76251e8e8f704ed7eace603a8041458a1ed16f</id>
<content type='text'>
Update copyright ownership/year information for target-core,
loopback, iscsi-target, tcm_qla2xx, vhost and iser-target.

Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Update copyright ownership/year information for target-core,
loopback, iscsi-target, tcm_qla2xx, vhost and iser-target.

Signed-off-by: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Add Third Party Copy (3PC) bit in INQUIRY response</title>
<updated>2013-09-10T23:48:46+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@daterainc.com</email>
</author>
<published>2013-08-22T21:17:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d397a445f43c7ae9b35260f236a08d5b5760de3d'/>
<id>d397a445f43c7ae9b35260f236a08d5b5760de3d</id>
<content type='text'>
This patch adds the Third Party Copy (3PC) bit to signal support
for EXTENDED_COPY within standard inquiry response data.

Also add emulate_3pc device attribute in configfs (enabled by default)
to allow the exposure of this bit to be disabled, if necessary.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Cc: Zach Brown &lt;zab@redhat.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This patch adds the Third Party Copy (3PC) bit to signal support
for EXTENDED_COPY within standard inquiry response data.

Also add emulate_3pc device attribute in configfs (enabled by default)
to allow the exposure of this bit to be disabled, if necessary.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Cc: Zach Brown &lt;zab@redhat.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Add global device list for EXTENDED_COPY</title>
<updated>2013-09-10T23:48:40+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@daterainc.com</email>
</author>
<published>2013-08-22T18:33:37+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d9ea32bff2c55d4cd4654f1e98d269a758f34534'/>
<id>d9ea32bff2c55d4cd4654f1e98d269a758f34534</id>
<content type='text'>
EXTENDED_COPY needs to be able to search a global list of devices
based on NAA WWN device identifiers, so add a simple g_device_list
protected by g_device_mutex.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Cc: Zach Brown &lt;zab@redhat.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
EXTENDED_COPY needs to be able to search a global list of devices
based on NAA WWN device identifiers, so add a simple g_device_list
protected by g_device_mutex.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: Roland Dreier &lt;roland@purestorage.com&gt;
Cc: Zach Brown &lt;zab@redhat.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>target: Add support for COMPARE_AND_WRITE emulation</title>
<updated>2013-09-10T23:41:59+00:00</updated>
<author>
<name>Nicholas Bellinger</name>
<email>nab@daterainc.com</email>
</author>
<published>2013-08-19T22:20:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=68ff9b9b27525cdaaea81890456f65aed5ce0b70'/>
<id>68ff9b9b27525cdaaea81890456f65aed5ce0b70</id>
<content type='text'>
This patch adds support for COMPARE_AND_WRITE emulation on a per block
basis.  This logic is used as an atomic test and set primative currently
used by VMWare ESX VAAI for performing array side locking of individual
VMFS extent ownership.

This includes the COMPARE_AND_WRITE CDB parsing within sbc_parse_cdb(),
and does the majority of the work within the compare_and_write_callback()
to perform the verify instance user data comparision, and subsequent
write instance user data I/O submission upon a successfull comparision.

The synchronization is enforced by se_device-&gt;caw_sem, that is obtained
before the initial READ I/O submission in sbc_compare_and_write().  The
mutex is then released upon MISCOMPARE in compare_and_write_callback(),
or upon WRITE instance user-data completion in compare_and_write_post().

The implementation currently assumes a single logical block (NoLB=1).

v4 changes:
 - Explicitly clear cmd-&gt;transport_complete_callback for two failure
   cases in sbc_compare_and_write() in order to avoid double unlock
   of -&gt;caw_sem in compare_and_write_callback() (Dan Carpenter)

v3 changes:
 - Convert se_device-&gt;caw_mutex to -&gt;caw_sem

v2 changes:
 - Set SCF_COMPARE_AND_WRITE and cmd-&gt;execute_cmd() to
   sbc_compare_and_write() during setup in sbc_parse_cdb()
 - Use sbc_compare_and_write() for initial READ submission with
   DMA_FROM_DEVICE
 - Reset cmd-&gt;execute_cmd() to sbc_execute_rw() for write instance
   user-data in compare_and_write_callback()
 - Drop SCF_BIDI command flag usage
 - Set TRANSPORT_PROCESSING + transport_state flags before write
   instance submission, and convert to __target_execute_cmd()
 - Prevent sbc_get_size() from being being called twice to
   generate incorrect size in sbc_parse_cdb()
 - Enforce se_device-&gt;caw_mutex synchronization between initial
   READ I/O submission, and final WRITE I/O completion.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
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<pre>
This patch adds support for COMPARE_AND_WRITE emulation on a per block
basis.  This logic is used as an atomic test and set primative currently
used by VMWare ESX VAAI for performing array side locking of individual
VMFS extent ownership.

This includes the COMPARE_AND_WRITE CDB parsing within sbc_parse_cdb(),
and does the majority of the work within the compare_and_write_callback()
to perform the verify instance user data comparision, and subsequent
write instance user data I/O submission upon a successfull comparision.

The synchronization is enforced by se_device-&gt;caw_sem, that is obtained
before the initial READ I/O submission in sbc_compare_and_write().  The
mutex is then released upon MISCOMPARE in compare_and_write_callback(),
or upon WRITE instance user-data completion in compare_and_write_post().

The implementation currently assumes a single logical block (NoLB=1).

v4 changes:
 - Explicitly clear cmd-&gt;transport_complete_callback for two failure
   cases in sbc_compare_and_write() in order to avoid double unlock
   of -&gt;caw_sem in compare_and_write_callback() (Dan Carpenter)

v3 changes:
 - Convert se_device-&gt;caw_mutex to -&gt;caw_sem

v2 changes:
 - Set SCF_COMPARE_AND_WRITE and cmd-&gt;execute_cmd() to
   sbc_compare_and_write() during setup in sbc_parse_cdb()
 - Use sbc_compare_and_write() for initial READ submission with
   DMA_FROM_DEVICE
 - Reset cmd-&gt;execute_cmd() to sbc_execute_rw() for write instance
   user-data in compare_and_write_callback()
 - Drop SCF_BIDI command flag usage
 - Set TRANSPORT_PROCESSING + transport_state flags before write
   instance submission, and convert to __target_execute_cmd()
 - Prevent sbc_get_size() from being being called twice to
   generate incorrect size in sbc_parse_cdb()
 - Enforce se_device-&gt;caw_mutex synchronization between initial
   READ I/O submission, and final WRITE I/O completion.

Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Hannes Reinecke &lt;hare@suse.de&gt;
Cc: Martin Petersen &lt;martin.petersen@oracle.com&gt;
Cc: Chris Mason &lt;chris.mason@fusionio.com&gt;
Cc: James Bottomley &lt;JBottomley@Parallels.com&gt;
Cc: Nicholas Bellinger &lt;nab@linux-iscsi.org&gt;
Signed-off-by: Nicholas Bellinger &lt;nab@daterainc.com&gt;
</pre>
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