[PATCH] checkpatch: add check for the buggy while_each_thread()

[Sergey Dyasly <dserrg@gmail.com>]

Now it's preferable to use for_each_thread() instead of while_each_thread().
Add a check to checkpatch.pl in order to prevent any new usages of the buggy
while_each_thread() when possible.

Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Sergey Dyasly <dserrg@gmail.com>
---
 scripts/checkpatch.pl | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index f0bb6d6..0c5cc0b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3255,6 +3255,12 @@ sub process {
 			     "Prefer dev_$level(... to dev_printk(KERN_$orig, ...\n" . $herecurr);
 		}
 
+# Check for the buggy while_each_thread()
+		if ($line =~ /\bwhile_each_thread\(/) {
+			WARN("WHILE_EACH_THREAD",
+			     "Prefer to use for_each_thread() instead of the buggy while_each_thread(). See commit 0c740d0afc3bff0a097ad03a1c8df92757516f5c for details.\n" . $herecurr);
+		}
+
 # function brace can't be on same line, except for #defines of do while,
 # or if closed on same line
 		if (($line=~/$Type\s*$Ident\(.*\).*\s*{/) and
-- 
2.2.2