linux-toradex.git/drivers/scsi, branch v3.0.85

SCSI: sd: fix array cache flushing bug causing performance problems

2013-05-19T17:04:38+00:00

commit 39c60a0948cc06139e2fbfe084f83cb7e7deae3b upstream.

Some arrays synchronize their full non volatile cache when the sd driver sends
a SYNCHRONIZE CACHE command.  Unfortunately, they can have Terrabytes of this
and we send a SYNCHRONIZE CACHE for every barrier if an array reports it has a
writeback cache.  This leads to massive slowdowns on journalled filesystems.

The fix is to allow userspace to turn off the writeback cache setting as a
temporary measure (i.e. without doing the MODE SELECT to write it back to the
device), so even though the device reported it has a writeback cache, the
user, knowing that the cache is non volatile and all they care about is
filesystem correctness, can turn that bit off in the kernel and avoid the
performance ruinous (and safety irrelevant) SYNCHRONIZE CACHE commands.

The way you do this is add a 'temporary' prefix when performing the usual
cache setting operations, so

echo temporary write through > /sys/class/scsi_disk//cache_type

Reported-by: Ric Wheeler 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

SCSI: dc395x: uninitialized variable in device_alloc()

2013-03-14T18:32:04+00:00

commit 208afec4f3be8c51ad6eebe6611dd6d2ad2fa298 upstream.

This bug was introduced back in bitkeeper days in 2003.  We use
"dcb->dev_mode" before it has been initialized.

Signed-off-by: Dan Carpenter 
Acked-by: Oliver Neukum 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

SCSI: sd: Reshuffle init_sd to avoid crash

2013-01-28T04:46:28+00:00

commit afd5e34b2bb34881d3a789e62486814a49b47faa upstream.

scsi_register_driver will register a prep_fn() function, which
in turn migh need to use the sd_cdp_pool for DIF.
Which hasn't been initialised at this point, leading to
a crash. So reshuffle the init_sd() and exit_sd() paths
to have the driver registered last.

Signed-off-by: Joel D. Diaz 
Signed-off-by: Hannes Reinecke 
Signed-off-by: James Bottomley 
Cc: CAI Qian 
Signed-off-by: Greg Kroah-Hartman

SCSI: qla2xxx: Test and clear FCPORT_UPDATE_NEEDED atomically.

2013-01-17T16:43:54+00:00

commit a394aac88506159e047630fc90dc2242568382d8 upstream.

When the qla2xxx driver loses access to multiple, remote ports, there is a race
condition which can occur which will keep the request stuck on a scsi request
queue indefinitely.

This bad state occurred do to a race condition with how the FCPORT_UPDATE_NEEDED
bit is set in qla2x00_schedule_rport_del(), and how it is cleared in
qla2x00_do_dpc().  The problem port has its drport pointer set, but it has never
been processed by the driver to inform the fc transport that the port has been
lost.  qla2x00_schedule_rport_del() sets drport, and then sets the
FCPORT_UPDATE_NEEDED bit.  In qla2x00_do_dpc(), the port lists are walked and
any drport pointer is handled and the fc transport informed of the port loss,
then the FCPORT_UPDATE_NEEDED bit is cleared.  This leaves a race where the
dpc thread is processing one port removal, another port removal is marked
with a call to qla2x00_schedule_rport_del(), and the dpc thread clears the
bit for both removals, even though only the first removal was actually
handled.  Until another event occurs to set FCPORT_UPDATE_NEEDED, the later
port removal is never finished and qla2xxx stays in a bad state which causes
requests to become stuck on request queues.

This patch updates the driver to test and clear FCPORT_UPDATE_NEEDED
atomically.  This ensures the port state changes are processed and not lost.

Signed-off-by: David Jeffery 
Signed-off-by: Chad Dupuis 
Signed-off-by: Saurav Kashyap 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

SCSI: mvsas: fix undefined bit shift

2013-01-17T16:43:54+00:00

commit beecadea1b8d67f591b13f7099559f32f3fd601d upstream.

The macro bit(n) is defined as ((u32)1 << n), and thus it doesn't work
with n >= 32, such as in mvs_94xx_assign_reg_set():

	if (i >= 32) {
		mvi->sata_reg_set |= bit(i);
		...
	}

The shift ((u32)1 << n) with n >= 32 also leads to undefined behavior.
The result varies depending on the architecture.

This patch changes bit(n) to do a 64-bit shift.  It also simplifies
mv_ffc64() using __ffs64(), since invoking ffz() with ~0 is undefined.

Signed-off-by: Xi Wang 
Acked-by: Xiangliang Yu 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

SCSI: isci: copy fis 0x34 response into proper buffer

2012-12-03T20:59:13+00:00

commit 49bd665c5407a453736d3232ee58f2906b42e83c upstream.

SATA MICROCODE DOWNALOAD fails on isci driver. After receiving Register
Device to Host (FIS 0x34) frame Initiator resets phy.
In the frame handler routine response (FIS 0x34) was copied into wrong
buffer and upper layer did not receive any answer which resulted in
timeout and reset.
This patch corrects this bug.

Signed-off-by: Maciej Patelczyk 
Signed-off-by: Lukasz Dorau 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

drivers/scsi/atp870u.c: fix bad use of udelay

2012-10-12T20:28:03+00:00

commit 0f6d93aa9d96cc9022b51bd10d462b03296be146 upstream.

The ACARD driver calls udelay() with a value > 2000, which leads to to
the following compilation error on ARM:

  ERROR: "__bad_udelay" [drivers/scsi/atp870u.ko] undefined!
  make[1]: *** [__modpost] Error 1

This is because udelay is defined on ARM, roughly speaking, as

	#define udelay(n) ((n) > 2000 ? __bad_udelay() : \
		__const_udelay((n) * ((2199023U*HZ)>>11)))

The argument to __const_udelay is the number of jiffies to wait divided
by 4, but this does not work unless the multiplication does not
overflow, and that is what the build error is designed to prevent.  The
intended behavior can be achieved by using mdelay to call udelay
multiple times in a loop.

[jrnieder@gmail.com: adding context]
Signed-off-by: Martin Michlmayr 
Signed-off-by: Jonathan Nieder 
Cc: James Bottomley 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

SCSI: scsi_dh_alua: Enable STPG for unavailable ports

2012-10-07T15:27:27+00:00

commit e47f8976d8e573928824a06748f7bc82c58d747f upstream.

A quote from SPC-4: "While in the unavailable primary target port
asymmetric access state, the device server shall support those of
the following commands that it supports while in the active/optimized
state: [ ... ] d) SET TARGET PORT GROUPS; [ ... ]". Hence enable
sending STPG to a target port group that is in the unavailable state.

Signed-off-by: Bart Van Assche 
Reviewed-by: Mike Christie 
Acked-by: Hannes Reinecke 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

SCSI: scsi_remove_target: fix softlockup regression on hot remove

2012-10-07T15:27:27+00:00

commit bc3f02a795d3b4faa99d37390174be2a75d091bd upstream.

John reports:
 BUG: soft lockup - CPU#2 stuck for 23s! [kworker/u:8:2202]
 [..]
 Call Trace:
  [] scsi_remove_target+0xda/0x1f0
  [] sas_rphy_remove+0x55/0x60
  [] sas_rphy_delete+0x11/0x20
  [] sas_port_delete+0x25/0x160
  [] mptsas_del_end_device+0x183/0x270

...introduced by commit 3b661a9 "[SCSI] fix hot unplug vs async scan race".

Don't restart lookup of more stargets in the multi-target case, just
arrange to traverse the list once, on the assumption that new targets
are always added at the end.  There is no guarantee that the target will
change state in scsi_target_reap() so we can end up spinning if we
restart.

Acked-by: Jack Wang 
LKML-Reference: 
Reported-by: John Drescher 
Tested-by: John Drescher 
Signed-off-by: Dan Williams 
Signed-off-by: James Bottomley 
Signed-off-by: Greg Kroah-Hartman

isci: fix isci_pci_probe() generates warning on efi failure path

2012-10-07T15:27:27+00:00

commit 6d70a74ffd616073a68ae0974d98819bfa8e6da6 upstream.

The oem parameter image embedded in the efi variable is at an offset
from the start of the variable.  However, in the failure path we try to
free the 'orom' pointer which is only valid when the paramaters are
being read from the legacy option-rom space.

Since failure to load the oem parameters is unlikely and we keep the
memory around in the success case just defer all de-allocation to devm.

Reported-by: Don Morris 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman