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>

1 files changed, 9 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f88bb3e21cda..826cdbac0114 100755
--- 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