linux.git/drivers/scsi/libiscsi.c, branch v3.15

Merge tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband

2014-04-03T23:57:19+00:00

Pull infiniband updates from Roland Dreier:
 "Main batch of InfiniBand/RDMA changes for 3.15:

   - The biggest change is core API extensions and mlx5 low-level driver
     support for handling DIF/DIX-style protection information, and the
     addition of PI support to the iSER initiator.  Target support will
     be arriving shortly through the SCSI target tree.

   - A nice simplification to the "umem" memory pinning library now that
     we have chained sg lists.  Kudos to Yishai Hadas for realizing our
     code didn't have to be so crazy.

   - Another nice simplification to the sg wrappers used by qib, ipath
     and ehca to handle their mapping of memory to adapter.

   - The usual batch of fixes to bugs found by static checkers etc.
     from intrepid people like Dan Carpenter and Yann Droneaud.

   - A large batch of cxgb4, ocrdma, qib driver updates"

* tag 'rdma-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/roland/infiniband: (102 commits)
  RDMA/ocrdma: Unregister inet notifier when unloading ocrdma
  RDMA/ocrdma: Fix warnings about pointer <-> integer casts
  RDMA/ocrdma: Code clean-up
  RDMA/ocrdma: Display FW version
  RDMA/ocrdma: Query controller information
  RDMA/ocrdma: Support non-embedded mailbox commands
  RDMA/ocrdma: Handle CQ overrun error
  RDMA/ocrdma: Display proper value for max_mw
  RDMA/ocrdma: Use non-zero tag in SRQ posting
  RDMA/ocrdma: Memory leak fix in ocrdma_dereg_mr()
  RDMA/ocrdma: Increment abi version count
  RDMA/ocrdma: Update version string
  be2net: Add abi version between be2net and ocrdma
  RDMA/ocrdma: ABI versioning between ocrdma and be2net
  RDMA/ocrdma: Allow DPP QP creation
  RDMA/ocrdma: Read ASIC_ID register to select asic_gen
  RDMA/ocrdma: SQ and RQ doorbell offset clean up
  RDMA/ocrdma: EQ full catastrophe avoidance
  RDMA/cxgb4: Disable DSGL use by default
  RDMA/cxgb4: rx_data() needs to hold the ep mutex
  ...

SCSI/libiscsi: Add check_protection callback for transports

2014-03-18T05:33:58+00:00

iSCSI needs to be at least aware that a task involves protection
information.  In case it does, after the transaction completed libiscsi
will ask the transport to check the protection status of the
transaction.

Unlike transport errors, DIF errors should not prevent successful
completion of the transaction from the transport point of view, but
should be escelated to scsi mid-layer when constructing the scsi
result and sense data.

check_protection routine will return the ascq corresponding to the DIF
error that occured (or 0 if no error happened).

return ascq:
- 0x1: GUARD_CHECK_FAILED
- 0x2: APPTAG_CHECK_FAILED
- 0x3: REFTAG_CHECK_FAILED

Signed-off-by: Sagi Grimberg 
Signed-off-by: Alex Tabachnik 
Signed-off-by: Roland Dreier

[SCSI] libiscsi: remove unneeded queue work when max_cmdsn is increased

2014-03-15T17:19:18+00:00

iscsi_queuecommand will only take in commands that can fit in the
current window. So, if a command is on the cmdqueue then it can
fit in the current window. If a command is on the mgmtqueue, then
we are setting the immediate bit so they will also fit in the
window. As a result, we never need to to do a iscsi_conn_queue_work
when the maxCmdSn is increased.

What should happen is that a command will complete the window will
be increased, then the scsi layer will send us more commands by
running the scsi_device queues.

Signed-off-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] libiscsi: Reduce locking contention in fast path

2014-03-15T17:19:18+00:00

Replace the session lock with two locks, a forward lock and
a backwards lock named frwd_lock and back_lock respectively.

The forward lock protects resources that change while sending a
request to the target, such as cmdsn, queued_cmdsn, and allocating
task from the commands' pool with kfifo_out.

The backward lock protects resources that change while processing
a response or in error path, such as cmdsn_exp, cmdsn_max, and
returning tasks to the commands' pool with kfifo_in.

Under a steady state fast-path situation, that is when one
or more processes/threads submit IO to an iscsi device and
a single kernel upcall (e.g softirq) is dealing with processing
of responses without errors, this patch eliminates the contention
between the queuecommand()/request response/scsi_done() flows
associated with iscsi sessions.

Between the forward and the backward locks exists a strict locking
hierarchy. The mutual exclusion zone protected by the forward lock can
enclose the mutual exclusion zone protected by the backward lock but not
vice versa.

For example, in iscsi_conn_teardown or in iscsi_xmit_data when there is
a failure and __iscsi_put_task is called, the backward lock is taken while
the forward lock is still taken. On the other hand, if in the RX path a nop
is to be sent, for example in iscsi_handle_reject or __iscsi_complete_pdu
than the forward lock is released and the backward lock is taken for the
duration of iscsi_send_nopout, later the backward lock is released and the
forward lock is retaken.

libiscsi_tcp uses two kernel fifos the r2t pool and the r2t queue.

The insertion and deletion from these queues didn't corespond to the
assumption taken by the new forward/backwards session locking paradigm.

That is, in iscsi_tcp_clenup_task which belongs to the RX (backwards)
path, r2t is taken out from r2t queue and inserted to the r2t pool.
In iscsi_tcp_get_curr_r2t which belong to the TX (forward) path, r2t
is also inserted to the r2t pool and another r2t is pulled from r2t
queue.

Only in iscsi_tcp_r2t_rsp which is called in the RX path but can requeue
to the TX path, r2t is taken from the r2t pool and inserted to the r2t
queue.

In order to cope with this situation, two spin locks were added,
pool2queue and queue2pool. The former protects extracting from the
r2t pool and inserting to the r2t queue, and the later protects the
extracing from the r2t queue and inserting to the r2t pool.

Signed-off-by: Shlomo Pongratz 
Signed-off-by: Or Gerlitz 
[minor fix up to apply cleanly and compile fix]
Signed-off-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] iscsi: fix wrong order of opcode and itt in iscsi_handle_reject prompt

2014-03-15T17:19:00+00:00

This patch makes reject messages show right value for opcode and itt, which
is converse previously.

Signed-off-by: Vaughan Cao 
Acked-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] libiscsi: Add local_ipaddr parameter in iscsi_conn struct

2013-12-20T04:56:26+00:00

Add local_ipaddr param and support get/set operations on it.

Signed-off-by: Adheer Chandravanshi 
Signed-off-by: Vikas Chaudhary 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] IB/iser: Add Discovery support

2013-08-26T14:53:49+00:00

To run discovery over iSER we need to advertize the CAP_TEXT_NEGO capability
towards user space. Also need to make sure the login RX buffer is posted when
SendTargets TEXT PDUs are sent. For that end, we use a setting of the
ISCSI_PARAM_DISCOVERY_SESS iscsi param as an indication that this is
discovery session.

Signed-off-by: Or Gerlitz 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] libiscsi: Add missing prints for session and connection sysfs attrs

2013-08-23T17:46:31+00:00

Signed-off-by: Adheer Chandravanshi 
Signed-off-by: Vikas Chaudhary 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] libiscsi: Add a missing break statement

2013-08-23T17:45:30+00:00

Signed-off-by: Adheer Chandravanshi 
Signed-off-by: Vikas Chaudhary 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley

[SCSI] libiscsi: Exporting new attrs for iscsi session and connection in sysfs

2013-08-23T17:10:16+00:00

Signed-off-by: Adheer Chandravanshi 
Signed-off-by: Vikas Chaudhary 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley