checkpatch: add checks for in_atomic()

in_atomic() is not for driver use so report any such use as an ERROR.
Also in_atomic() is often used to determine if we may sleep, but it is not
reliable in this use model therefore strongly discourage its use.

Signed-off-by: Andy Whitcroft <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
1 file changed