linux-toradex.git/drivers/scsi/libiscsi.c, branch v4.9.52

scsi: libiscsi: add lock around task lists to fix list corruption regression

2017-03-26T11:05:58+00:00

commit 6f8830f5bbab16e54f261de187f3df4644a5b977 upstream.

There's a rather long standing regression from the commit "libiscsi:
Reduce locking contention in fast path"

Depending on iSCSI target behavior, it's possible to hit the case in
iscsi_complete_task where the task is still on a pending list
(!list_empty(&task->running)).  When that happens the task is removed
from the list while holding the session back_lock, but other task list
modification occur under the frwd_lock.  That leads to linked list
corruption and eventually a panicked system.

Rather than back out the session lock split entirely, in order to try
and keep some of the performance gains this patch adds another lock to
maintain the task lists integrity.

Major enterprise supported kernels have been backing out the lock split
for while now, thanks to the efforts at IBM where a lab setup has the
most reliable reproducer I've seen on this issue.  This patch has been
tested there successfully.

Signed-off-by: Chris Leech 
Fixes: 659743b02c41 ("[SCSI] libiscsi: Reduce locking contention in fast path")
Reported-by: Prashantha Subbarao 
Reviewed-by: Guilherme G. Piccoli 
Signed-off-by: Martin K. Petersen 
Signed-off-by: Greg Kroah-Hartman

scsi: libiscsi: Fix locking in __iscsi_conn_send_pdu

2016-10-17T17:34:44+00:00

The code at free_task label in __iscsi_conn_send_pdu can get executed
from blk_timeout_work which takes queue_lock using spin_lock_irq.
back_lock taken with spin_unlock_bh will cause WARN_ON_ONCE.  The code
gets executed either with bottom half or IRQ disabled hence using
spin_lock/spin_unlock for back_lock is safe.

Signed-off-by: Jitendra Bhivare 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Chris Leech 
Signed-off-by: Martin K. Petersen

libiscsi: Remove set-but-not-used variables

2016-04-11T20:57:09+00:00

Avoid that building with W=1 causes gcc to report warnings about
set-but-not-used variables.

Signed-off-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Martin K. Petersen

libiscsi: Unexport iscsi_eh_target_reset()

2016-04-11T20:57:09+00:00

Running "git grep -nHw iscsi_eh_target_reset" shows that this function
is only called from inside the drivers/scsi/libiscsi.c source
file. Hence unexport this function.

Signed-off-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Martin K. Petersen

libiscsi: Fix iscsi_check_transport_timeouts possible infinite loop

2015-09-17T14:25:02+00:00

Connection last_ping is not being updated when iscsi_send_nopout fails.
Not updating the last_ping will cause firing a timer to a past time
(last_ping + ping_tmo < current_time) which triggers an infinite loop of
iscsi_check_transport_timeouts() and hogs the cpu.

Fix this issue by checking the return value of iscsi_send_nopout.
If it fails set the next_timeout to one second later.

Signed-off-by: Ariel Nahum 
Signed-off-by: Sagi Grimberg 
Reviewed-by: Mike Christie 
Signed-off-by: James Bottomley

Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending

2015-09-12T02:00:42+00:00

Pull SCSI target updates from Nicholas Bellinger:
 "Here are the outstanding target-pending updates for v4.3-rc1.

  Mostly bug-fixes and minor changes this round.  The fallout from the
  big v4.2-rc1 RCU conversion have (thus far) been minimal.

  The highlights this round include:

   - Move sense handling routines into scsi_common code (Sagi)

   - Return ABORTED_COMMAND sense key for PI errors (Sagi)

   - Add tpg_enabled_sendtargets attribute for disabled iscsi-target
     discovery (David)

   - Shrink target struct se_cmd by rearranging fields (Roland)

   - Drop iSCSI use of mutex around max_cmd_sn increment (Roland)

   - Replace iSCSI __kernel_sockaddr_storage with sockaddr_storage (Andy +
     Chris)

   - Honor fabric max_data_sg_nents I/O transfer limit (Arun + Himanshu +
     nab)

   - Fix EXTENDED_COPY >= v4.1 regression OOPsen (Alex + nab)"

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (37 commits)
  target: use stringify.h instead of own definition
  target/user: Fix UFLAG_UNKNOWN_OP handling
  target: Remove no-op conditional
  target/user: Remove unused variable
  target: Fix max_cmd_sn increment w/o cmdsn mutex regressions
  target: Attach EXTENDED_COPY local I/O descriptors to xcopy_pt_sess
  target/qla2xxx: Honor max_data_sg_nents I/O transfer limit
  target/iscsi: Replace __kernel_sockaddr_storage with sockaddr_storage
  target/iscsi: Replace conn->login_ip with login_sockaddr
  target/iscsi: Keep local_ip as the actual sockaddr
  target/iscsi: Fix np_ip bracket issue by removing np_ip
  target: Drop iSCSI use of mutex around max_cmd_sn increment
  qla2xxx: Update tcm_qla2xxx module description to 24xx+
  iscsi-target: Add tpg_enabled_sendtargets for disabled discovery
  drivers: target: Drop unlikely before IS_ERR(_OR_NULL)
  target: check DPO/FUA usage for COMPARE AND WRITE
  target: Shrink struct se_cmd by rearranging fields
  target: Remove cmd->se_ordered_id (unused except debug log lines)
  target: add support for START_STOP_UNIT SCSI opcode
  target: improve unsupported opcode message
  ...

libiscsi: Fix host busy blocking during connection teardown

2015-08-12T17:21:20+00:00

In case of hw iscsi offload, an host can have N-number of active
connections. There can be IO's running on some connections which
make host->host_busy always TRUE. Now if logout from a connection
is tried then the code gets into an infinite loop as host->host_busy
is always TRUE.

 iscsi_conn_teardown(....)
 {
   .........
    /*
     * Block until all in-progress commands for this connection
     * time out or fail.
     */
     for (;;) {
      spin_lock_irqsave(session->host->host_lock, flags);
      if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */
	      spin_unlock_irqrestore(session->host->host_lock, flags);
              break;
      }
     spin_unlock_irqrestore(session->host->host_lock, flags);
     msleep_interruptible(500);
     iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
                 "host_busy %d host_failed %d\n",
	          atomic_read(&session->host->host_busy),
	          session->host->host_failed);

	................
	...............
     }
  }

This is not an issue with software-iscsi/iser as each cxn is a separate
host.

Fix:
Acquiring eh_mutex in iscsi_conn_teardown() before setting
session->state = ISCSI_STATE_TERMINATE.

Signed-off-by: John Soni Jose 
Reviewed-by: Mike Christie 
Reviewed-by: Chris Leech 
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley

libiscsi: Use scsi helper to set information descriptor

2015-07-24T05:55:27+00:00

In case encountered a PI error, use scsi_set_sense_information
instead of open coding information descriptor format.

Signed-off-by: Sagi Grimberg 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Signed-off-by: Nicholas Bellinger

scsi: drop reason argument from ->change_queue_depth

2014-11-24T13:45:27+00:00

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: Christoph Hellwig 
Reviewed-by: Mike Christie 
Reviewed-by: Hannes Reinecke

scsi: avoid ->change_queue_depth indirection for queue full tracking

2014-11-24T13:45:12+00:00

All drivers use the implementation for ramping the queue up and down, so
instead of overloading the change_queue_depth method call the
implementation diretly if the driver opts into it by setting the
track_queue_depth flag in the host template.

Note that a few drivers validated the new queue depth in their
change_queue_depth method, but as we never go over the queue depth
set during slave_configure or the sysfs file this isn't nessecary
and can safely be removed.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Mike Christie 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Venkatesh Srinivas