linux-stable.git/drivers/s390, branch v3.2.49

zfcp: status read buffers on first adapter open with link down

2013-07-27T04:34:05+00:00

commit 9edf7d75ee5f21663a0183d21f702682d0ef132f upstream.

Commit 64deb6efdc5504ce97b5c1c6f281fffbc150bd93
"[SCSI] zfcp: Use status_read_buf_num provided by FCP channel"
started using a value returned by the channel but only evaluated the value
if the fabric link is up.
Commit 8d88cf3f3b9af4713642caeb221b6d6a42019001
"[SCSI] zfcp: Update status read mempool"
introduced mempool resizings based on the above value.
On setting an FCP device online for the very first time since boot, a new
zeroed adapter object is allocated. If the link is down, the number of
status read requests remains zero. Since just the config data exchange is
incomplete, we proceed with adapter open recovery. However, we
unconditionally call mempool_resize with adapter->stat_read_buf_num == 0 in
this case.

This causes a kernel message "kernel BUG at mm/mempool.c:131!" in process
"zfcperp" with last function mempool_resize in Krnl PSW
and zfcp_erp_thread in the Call Trace.

Don't evaluate channel values which are invalid on link down. The number of
status read requests is always valid, evaluated, and set to a positive
minimum greater than zero. The adapter open recovery can proceed and the
channel has status read buffers to inform us on a future link up event.
While we are not aware of any other code path that could result in mempool
resize attempts of size zero, we still also initialize the number of status
read buffers to be posted to a static minimum number on adapter object
allocation.

Signed-off-by: Steffen Maier 
Signed-off-by: James Bottomley 
[bwh: Backported to 3.2:
 - Copyright notice changed slightly
 - Don't use zfcp_fsf_convert_portspeed()]
Signed-off-by: Ben Hutchings

zfcp: block queue limits with data router

2013-07-27T04:34:05+00:00

commit 5fea4291deacd80188b996d2f555fc6a1940e5d4 upstream.

Commit 86a9668a8d29ea711613e1cb37efa68e7c4db564
"[SCSI] zfcp: support for hardware data router"
reduced the initial block queue limits in the scsi_host_template to the
absolute minimum and adjusted them later on. However, the adjustment was
too late for the BSG devices of Scsi_Host and fc_host.

Therefore, ioctl(..., SG_IO, ...) with request or response size > 4kB to a
BSG device of an fc_host or a Scsi_Host fails with EINVAL. As a result,
users of such ioctl such as HBA_SendCTPassThru() in libzfcphbaapi return
with error HBA_STATUS_ERROR.

Initialize the block queue limits in zfcp_scsi_host_template to the
greatest common denominator (GCD).

While we cannot exploit the slightly enlarged maximum request size with
data router, this should be neglectible. Doing so also avoids running into
trouble after live guest relocation (LGR) / migration from a data router
FCP device to an FCP device that does not support data router. In that
case, zfcp would figure out the new limits on adapter recovery, but the
fc_host and Scsi_Host (plus in fact all sdevs) still exist with the old and
now too large queue limits.

It should also OK, not to use half the size as in the DIX case, because
fc_host and Scsi_Host do not transport FCP requests including SCSI commands
using protection data.

Signed-off-by: Steffen Maier 
Reviewed-by: Martin Peschke 
Signed-off-by: James Bottomley 
[bwh: Backported to 3.2: copyright notice changed slightly]
Signed-off-by: Ben Hutchings

zfcp: fix adapter (re)open recovery while link to SAN is down

2013-07-27T04:34:05+00:00

commit f76ccaac4f82c463a037aa4a1e4ccb85c7011814 upstream.

FCP device remains in status ERP_FAILED when device is switched online
or adapter recovery is triggered  while link to SAN is down.

When Exchange Configuration Data command returns the FSF status
FSF_EXCHANGE_CONFIG_DATA_INCOMPLETE it aborts the exchange process.
The only retries are done during the common error recovery procedure
(i.e. max. 3 retries with 8sec sleep between) and remains in status
ERP_FAILED with QDIO down.

This commit reverts the commit 0df138476c8306478d6e726f044868b4bccf411c
(zfcp: Fix adapter activation on link down).
When FSF status FSF_EXCHANGE_CONFIG_DATA_INCOMPLETE is received the
adapter recovery will be finished without any retries. QDIO will be
up now and status changes such as LINK UP will be received now.

Signed-off-by: Daniel Hansel 
Signed-off-by: Steffen Maier 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings

s390/memory hotplug: prevent offline of active memory increments

2013-05-13T14:02:27+00:00

commit 94c163663fc1dcfc067a5fb3cc1446b9469975ce upstream.

In case a machine supports memory hotplug all active memory increments
present at IPL time have been initialized with a "usecount" of 1.
This is wrong if the memory increment size is larger than the memory
section size of the memory hotplug code. If that is the case the
usecount must be initialized with the number of memory sections that
fit into one memory increment.
Otherwise it is possible to put a memory increment into standby state
even if there are still active sections.
Afterwards addressing exceptions might happen which cause the kernel
to panic.
However even worse, if a memory increment was put into standby state
and afterwards into active state again, it's contents would have been
zeroed, leading to memory corruption.

This was only an issue for machines that support standby memory and
have at least 256GB memory.

This is broken since commit fdb1bb15 "[S390] sclp/memory hotplug: fix
initial usecount of increments".

Signed-off-by: Heiko Carstens 
Reviewed-by: Gerald Schaefer 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Ben Hutchings

KVM: s390: Handle hosts not supporting s390-virtio.

2013-03-06T03:22:34+00:00

commit 55c171a6d90dc0574021f9c836127cfd1a7d2e30 upstream.

Running under a kvm host does not necessarily imply the presence of
a page mapped above the main memory with the virtio information;
however, the code includes a hard coded access to that page.

Instead, check for the presence of the page and exit gracefully
before we hit an addressing exception if it does not exist.

Reviewed-by: Marcelo Tosatti 
Reviewed-by: Alexander Graf 
Signed-off-by: Cornelia Huck 
Signed-off-by: Gleb Natapov 
Signed-off-by: Ben Hutchings

s390/cio: fix pgid reserved check

2013-01-03T03:33:26+00:00

commit d99e79ec5574fc556c988f613ed6175f6de66f4a upstream.

The check to whom a device is reserved is done by checking the path
state of the affected channel paths. If it turns out that one path is
flagged as reserved by someone else the whole device is marked as such.

However the meaning of the RESVD_ELSE bit is that the addressed device
is reserved to a different pathgroup (and not reserved to a different
LPAR). If we do this test on a path which is currently not a member of
the pathgroup we could erroneously mark the device as reserved to
someone else.

To fix this collect the reserved state for all potential members of the
pathgroup and only mark the device as reserved if all of those potential
members have the RESVD_ELSE bit set.

Acked-by: Peter Oberparleiter 
Signed-off-by: Sebastian Ott 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Ben Hutchings

zfcp: only access zfcp_scsi_dev for valid scsi_device

2012-10-17T02:48:48+00:00

commit d436de8ce25f53a8a880a931886821f632247943 upstream.

__scsi_remove_device (e.g. due to dev_loss_tmo) calls
zfcp_scsi_slave_destroy which in turn sends a close LUN FSF request to
the adapter. After 30 seconds without response,
zfcp_erp_timeout_handler kicks the ERP thread failing the close LUN
ERP action. zfcp_erp_wait in zfcp_erp_lun_shutdown_wait and thus
zfcp_scsi_slave_destroy returns and then scsi_device is no longer
valid. Sometime later the response to the close LUN FSF request may
finally come in. However, commit
b62a8d9b45b971a67a0f8413338c230e3117dff5
"[SCSI] zfcp: Use SCSI device data zfcp_scsi_dev instead of zfcp_unit"
introduced a number of attempts to unconditionally access struct
zfcp_scsi_dev through struct scsi_device causing a use-after-free.
This leads to an Oops due to kernel page fault in one of:
zfcp_fsf_abort_fcp_command_handler, zfcp_fsf_open_lun_handler,
zfcp_fsf_close_lun_handler, zfcp_fsf_req_trace,
zfcp_fsf_fcp_handler_common.
Move dereferencing of zfcp private data zfcp_scsi_dev allocated in
scsi_device via scsi_transport_reserve_device after the check for
potentially aborted FSF request and thus no longer valid scsi_device.
Only then assign sdev_to_zfcp(sdev) to the local auto variable struct
zfcp_scsi_dev *zfcp_sdev.

Signed-off-by: Martin Peschke 
Signed-off-by: Steffen Maier 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings

zfcp: restore refcount check on port_remove

2012-10-17T02:48:47+00:00

commit d99b601b63386f3395dc26a699ae703a273d9982 upstream.

Upstream commit f3450c7b917201bb49d67032e9f60d5125675d6a
"[SCSI] zfcp: Replace local reference counting with common kref"
accidentally dropped a reference count check before tearing down
zfcp_ports that are potentially in use by zfcp_units.
Even remote ports in use can be removed causing
unreachable garbage objects zfcp_ports with zfcp_units.
Thus units won't come back even after a manual port_rescan.
The kref of zfcp_port->dev.kobj is already used by the driver core.
We cannot re-use it to track the number of zfcp_units.
Re-introduce our own counter for units per port
and check on port_remove.

Signed-off-by: Steffen Maier 
Reviewed-by: Heiko Carstens 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings

zfcp: remove invalid reference to list iterator variable

2012-10-17T02:48:46+00:00

commit ca579c9f136af4274ccfd1bcaee7f38a29a0e2e9 upstream.

If list_for_each_entry, etc complete a traversal of the list, the iterator
variable ends up pointing to an address at an offset from the list head,
and not a meaningful structure.  Thus this value should not be used after
the end of the iterator.  Replace port->adapter->scsi_host by
adapter->scsi_host.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Oversight in upsteam commit of v2.6.37
a1ca48319a9aa1c5b57ce142f538e76050bb8972
"[SCSI] zfcp: Move ACL/CFDC code to zfcp_cfdc.c"
which merged the content of zfcp_erp_port_access_changed().

Signed-off-by: Julia Lawall 
Signed-off-by: Steffen Maier 
Reviewed-by: Martin Peschke 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings

zfcp: Do not wakeup while suspended

2012-10-17T02:48:46+00:00

commit cb45214960bc989af8b911ebd77da541c797717d upstream.

If the mapping of FCP device bus ID and corresponding subchannel
is modified while the Linux image is suspended, the resume of FCP
devices can fail. During resume, zfcp gets callbacks from cio regarding
the modified subchannels but they can be arbitrarily mixed with the
restore/resume callback. Since the cio callbacks would trigger
adapter recovery, zfcp could wakeup before the resume callback.
Therefore, ignore the cio callbacks regarding subchannels while
being suspended. We can safely do so, since zfcp does not deal itself
with subchannels. For problem determination purposes, we still trace the
ignored callback events.

The following kernel messages could be seen on resume:

kernel: : parent  should not be sleeping

As part of adapter reopen recovery, zfcp performs auto port scanning
which can erroneously try to register new remote ports with
scsi_transport_fc and the device core code complains about the parent
(adapter) still sleeping.

kernel: zfcp.3dff9c: :\
 Setting up the QDIO connection to the FCP adapter failed

kernel: zfcp.574d43: :\
 ERP cannot recover an error on the FCP device

In such cases, the adapter gave up recovery and remained blocked along
with its child objects: remote ports and LUNs/scsi devices. Even the
adapter shutdown as part of giving up recovery failed because the ccw
device state remained disconnected. Later, the corresponding remote
ports ran into dev_loss_tmo. As a result, the LUNs were erroneously
not available again after resume.

Even a manually triggered adapter recovery (e.g. sysfs attribute
failed, or device offline/online via sysfs) could not recover the
adapter due to the remaining disconnected state of the corresponding
ccw device.

Signed-off-by: Steffen Maier 
Signed-off-by: James Bottomley 
Signed-off-by: Ben Hutchings