Add the devfs_fp_check() function which helps us get from a struct file to a cdev and a devsw, doing all the relevant checks along the way.
Add the devfs_fp_check() function which helps us get from a struct file
to a cdev and a devsw, doing all the relevant checks along the way.

Add the check to see if fp->f_vnode->v_rdev differs from our cached
fp->f_data copy of our cdev.  If it does the device was revoked and
we return ENXIO.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase