scsi_dh: add a common helper to get a scsi_device from a request_queue
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 <923f7720577207a44b32e59bbfbea59d27f1ae8e@lst.de>
Reviewed-by: Martin K. Petersen <0384aaef27f06874adbdb09a807bb339f4aff9fd@oracle.com>
Reviewed-by: Hannes Reinecke <b0d1e9e4a4e27620745ff49be9000da3174a4cc6@suse.de>
Signed-off-by: James Bottomley <1acebbdca565c7b6b638bdc23b58b5610d1a56b8@Odin.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs