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 <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f88bb3e..826cdba 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2466,6 +2466,15 @@ sub process {
                                last;
                        }
                }
+
+# whine mightly about in_atomic
+               if ($line =~ /\bin_atomic\s*\(/) {
+                       if ($realfile =~ m@^drivers/@) {
+                               ERROR("do not use in_atomic in drivers\n" . $herecurr);
+                       } else {
+                               WARN("use of in_atomic() is incorrect outside core kernel code\n" . $herecurr);
+                       }
+               }
        }
 
        # If we have no input at all, then there is nothing to report on