litmus-rt.git/drivers/scsi/libfc, branch linux-tip

SCSI host lock push-down

2010-11-16T21:33:23+00:00

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 
Acked-by: James Bottomley 
Signed-off-by: Linus Torvalds

[SCSI] libfc: Do not let disc work cancel itself

2010-10-25T20:11:37+00:00

When number of NPIV ports created are greater than the xids
allocated per pool -- for eg., creating 255 NPIV ports on a
system with nr_cpu_ids of 32, with each pool containing 128
xids -- and then generating a link event - for eg.,
shutdown/no shutdown -- on the switch port causes the hang
with the following stack trace.

Call Trace:
schedule_timeout+0x19d/0x230
wait_for_common+0xc0/0x170
__cancel_work_timer+0xcf/0x1b0
fc_disc_stop+0x16/0x30 [libfc]
fc_lport_reset_locked+0x47/0x90 [libfc]
fc_lport_enter_reset+0x67/0xe0 [libfc]
fc_lport_disc_callback+0xbc/0xe0 [libfc]
fc_disc_done+0xa8/0xf0 [libfc]
fc_disc_timeout+0x29/0x40 [libfc]
run_workqueue+0xb8/0x140
worker_thread+0x96/0x110
kthread+0x96/0xa0
child_rip+0xa/0x20

Fix is to not cancel the disc_work if discovery is already
stopped, thus allowing lport state machine to restart and try
discovery again.

Signed-off-by: Bhanu Prakash Gollapudi 
Acked-by: Joe Eykholt 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley

[SCSI] libfc: possible race could panic system due to NULL fsp->cmd

2010-10-25T20:11:35+00:00

It is unlikely but in case if it hits then it would cause panic
due to null cmd ptr, so far only one instance seen recently with
ESX though this was introduced long ago with this commit:-

commit c1ecb90a66c5afc7cc5c9349f9c3714eef4a5cfb
Author: Chris Leech 
Date:   Thu Dec 10 09:59:26 2009 -0800
[SCSI] libfc: reduce hold time on SCSI host lock

Currently fsp->cmd is set to NULL w/o scsi_queue_lock before
dequeuing from scsi_pkt_queue and that could cause NULL
fsp->cmd in fc_fcp_cleanup_each_cmd for cmd completing
with fsp->cmd = NULL after fc_fcp_cleanup_each_cmd taken
reference. No need to set fsp->cmd to NULL as this is also
protected by fc_fcp_lock_pkt(), for above race the
fc_fcp_lock_pkt() in fc_fcp_cleanup_each_cmd() will fail
as that cmd is  already done.

Mike mentioned same issue at
http://www.open-fcoe.org/pipermail/devel/2010-September/010533.html

Similarly moved sc_cmd->SCp.ptr = NULL under scsi_queue_lock so
that scsi abort error handler won't abort on completed cmds.

Signed-off-by: Vasu Dev 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley

[SCSI] libfc: adds flogi retry in case DID is zero in RJT

2010-10-25T20:11:32+00:00

Sometimes switch in NPV mode rejects flogi request with DID
zero and in that case flogi is not tried again and port
remains offline, so this patch validates DID for non zero
along with only ACC response to allow flogi retry
for RJT with DID=0 also succeed FLOGI in next try.

Signed-off-by: Vasu Dev 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley

[SCSI] libfc: use DID_TRANSPORT_DISRUPTED while lport not ready

2010-10-25T20:11:31+00:00

This is per Mile Christie feedback since in this case IO
could get retried for tape devices and therefore DID_REQUEUE
cannot be used, more details in this thread.

http://marc.info/?l=linux-scsi&m=127970522630136&w=2

Signed-off-by: Vasu Dev 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley

[SCSI] libfc: fix setting of rport dev loss

2010-10-25T20:11:29+00:00

There does not seem to be a reason why libfc adds a 5
second delay to the user requested value for the dev loss
tmo. There also does not seem to be a reason to allow
setting it to 0 (or really close).

This patch removes the extra 5 sec delay, and for 0 it
sets it to 1 like other fc drivers. We should actually
be able to set it to 0 since the queue_delayed_work API
will just call queue_work, but other drivers set it to 1 in
that case.

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

[SCSI] libfc: call fc_remote_port_chkready under the host lock.

2010-08-06T16:00:26+00:00

The rport port state and flags are set under the host lock,
so this patch calls fc_remote_port_chkready with the host lock
held like is also done in the other fc drivers.

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

Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2010-08-04T22:31:02+00:00

* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (48 commits)
  Documentation: update broken web addresses.
  fix comment typo "choosed" -> "chosen"
  hostap:hostap_hw.c Fix typo in comment
  Fix spelling contorller -> controller in comments
  Kconfig.debug: FAIL_IO_TIMEOUT: typo Faul -> Fault
  fs/Kconfig: Fix typo Userpace -> Userspace
  Removing dead MACH_U300_BS26
  drivers/infiniband: Remove unnecessary casts of private_data
  fs/ocfs2: Remove unnecessary casts of private_data
  libfc: use ARRAY_SIZE
  scsi: bfa: use ARRAY_SIZE
  drm: i915: use ARRAY_SIZE
  drm: drm_edid: use ARRAY_SIZE
  synclink: use ARRAY_SIZE
  block: cciss: use ARRAY_SIZE
  comment typo fixes: charater => character
  fix comment typos concerning "challenge"
  arm: plat-spear: fix typo in kerneldoc
  reiserfs: typo comment fix
  update email address
  ...

[SCSI] libfc: Add retry logic to lport state machine when receiving LS_RJT

2010-07-28T14:06:04+00:00

Call fc_lport_error to retry upto max retry count when
FLOGI/SCR/NS gets rejected.

Signed-off-by: Bhanu Prakash Gollapudi 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley

[SCSI] libfc: don't require a local exchange for incoming requests

2010-07-28T14:06:02+00:00

Incoming requests shouldn't require a local exchange if we're
just going to reply with one or two frames and don't expect
anything further.  Don't allocate exchanges for such requests
until requested by the upper-layer protocol.

The sequence is always NULL for new requests, so remove
that as an argument to request handlers.

Also change the first argument to lport->tt.seq_els_rsp_send
from the sequence pointer to the received frame pointer, to
supply the exchange IDs and destination ID info.

Signed-off-by: Joe Eykholt 
Signed-off-by: Robert Love 
Signed-off-by: James Bottomley