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Commit Graph

10 Commits

Author SHA1 Message Date
Christoph Hellwig
d6a32b9809 scsi_dh: don't try to load a device handler during async probing
Request_module gets really unhappy when called from async probing, so
revert to not auto load device handler modules during the SCSI bus
scan.  While autoloading would be really useful we never did this
until 4.3-rc and it turns out that functionality doesn't actually
work.

Fixes: 566079 ("dm-mpath, scsi_dh: request scsi_dh modules in scsi_dh, not dm-mpath")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Paul Mackerras <paulus@ozlabs.org>
Tested-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-10-27 15:03:31 +09:00
Junichi Nomura
23695e41a1 scsi_dh: fix use-after-free when removing scsi device
The commit 1bab0de027 ("dm-mpath, scsi_dh: don't let dm detach device
handlers") removed reference counting of attached scsi device handler.
As a result, handler data is freed immediately via scsi_dh->detach()
in the context of scsi_remove_device() where activation request can be
still in flight.

This patch moves scsi_dh_handler_detach() to sdev releasing function,
scsi_device_dev_release_usercontext(), at that point the device
is already in quiesced state.

Fixes: 1bab0de027 ("dm-mpath, scsi_dh: don't let dm detach device handlers")
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-10-27 11:22:37 +09:00
Paul Mackerras
1378889c56 scsi_dh: Use the correct module name when loading device handler
This fixes a bug in recent kernels which results in failure to boot
on systems that have multipath SCSI disks.  I observed this failure
on a POWER8 server where all the disks are multipath SCSI disks.
The symptoms are several messages like this on the console:

[    3.018700] device-mapper: table: 253:0: multipath: error attaching hardware handler
[    3.018828] device-mapper: ioctl: error adding target to table

and the system does not find its disks, and therefore fails to boot.

Bisection revealed that the bug was introduced in commit 566079c849,
"dm-mpath, scsi_dh: request scsi_dh modules in scsi_dh, not dm-mpath".
The specific reason for the failure is that where we previously loaded
the "scsi_dh_alua" module, we are now trying to load the "alua" module,
which doesn't exist.

To fix this, we change the request_module call in scsi_dh_lookup()
to prepend "scsi_dh_" to the name, just like the old code in
drivers/md/dm-mpath.c:parse_hw_handler() used to do.

[jejb: also fixes issue spotted by Sasha Levin that formatting
characters could be passed in via sysfs and cause issues with
request_module()]

Fixes: 566079c849
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-10-01 10:46:28 -07:00
Hannes Reinecke
710105fda7 scsi_dh: return SCSI_DH_NOTCONN in scsi_dh_activate()
When calling scsi_dh_activate() we should be returning
SCSI_DH_NOTCONN if the device handler couldn't be attached.

Reviewed-by: Bart van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:58 -07:00
Christoph Hellwig
d442277495 scsi_dh: don't allow to detach device handlers at runtime
The I/O submission and completion paths call into the device handler
without any synchronization agains detachment.  So disallow detaching
device handlers at runtime.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:58 -07:00
Christoph Hellwig
e959ed9a44 scsi_dh: add a common helper to get a scsi_device from a request_queue
And cleanup the various messy opencoded versions of this.  Note that this
moves the sdev_state checks outside the queue_lock coverage, but as
we don't hold the lock over the activation they are only advisory anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:57 -07:00
Christoph Hellwig
ee14c674e8 scsi_dh: kill struct scsi_dh_data
Add a ->handler and a ->handler_data field to struct scsi_device and kill
this indirection.  Also move struct scsi_device_handler to scsi_dh.h so that
changes to it don't require rebuilding every SCSI LLDD.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:57 -07:00
Christoph Hellwig
d95dbff2a4 scsi_dh: move device matching to the core code
Add a single list of devices that need non-ALUA device handlers to the core
scsi_dh code so that we can autoload the modules for them at probe time.

While this is a little ugly in terms of architecture it actually
significantly simplifies the code in addition to the new autoloading
functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:56 -07:00
Christoph Hellwig
086b91d052 scsi_dh: integrate into the core SCSI code
Stop building scsi_dh as a separate module and integrate it fully into the
core SCSI code with explicit callouts at bus scan time.  For now the
callouts are placed at the same point as the old bus notifiers were called,
but in the future we will be able to look at ALUA INQUIRY data earlier on.

Note that this also means that the device handler modules need to be loaded
by the time we scan the bus.  The next patches will add support for
autoloading device handlers at bus scan time to make sure they are always
loaded if they are enabled in the kernel config.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:56 -07:00
Christoph Hellwig
daaa858b7a scsi_dh: move to drivers/scsi
Prepare for building scsi_dh.c into the core SCSI module by moving it to
drivers/scsi.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
2015-08-28 13:14:55 -07:00