fbmem: make read/write/ioctl use the frame buffer at open time

read/write/ioctl on a fbcon file descriptor has traditionally used the
fbcon not when it was opened, but as it was at the time of the call.
That makes no sense, but the lack of sense is much more obvious now that
we properly ref-count the usage - it means that the ref-counting doesn't
actually protect operations we do on the frame buffer.

This changes it to look at the fb_info that we got at open time, but in
order to avoid using a frame buffer long after it has been unregistered,
we do verify that it is still current, and return -ENODEV if not.

Acked-by: Tim Gardner <[email protected]>
Tested-by: Daniel J Blueman <[email protected]>
Tested-by: Anca Emanuel <[email protected]>
Cc: Bruno Prémont <[email protected]>
Cc: Alan Cox <[email protected]>
Cc: Paul Mundt <[email protected]>
Cc: Dave Airlie <[email protected]>
Cc: Andy Whitcroft <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions