[SCSI] bsg: correct fault if queue object removed while dev_t open
[SCSI] bsg: correct fault if queue object removed while dev_t open

This patch corrects an issue in bsg that results in a general protection
fault if an LLD is removed while an application is using an open file
handle to a bsg device, and the application issues an ioctl. The fault
occurs because the class_dev is NULL, having been cleared in
bsg_unregister_queue() when the driver was removed.  With this
patch, a check is made for the class_dev, and the application
will receive ENXIO if the related object is gone.

Signed-off-by: Carl Lajeunesse <af9143bd28c3af755b244aae2e0f869acde5b6e2@emulex.com>
Signed-off-by: James Smart <2b041da073ece526f0738329b43a4ebfc495c725@emulex.com>
Signed-off-by: James Bottomley <407b36959ca09543ccda8f8e06721c791bc53435@suse.de>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas