checkpatch: warn when declaring "struct spinlock foo;"

spinlock_t should always be used.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: N"Luis R. Rodriguez" <mcgrof@do-not-panic.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -3336,6 +3336,12 @@ sub process {
 			     "Avoid line continuations in quoted strings\n" . $herecurr);
 		}
 
+# check for struct spinlock declarations
+		if ($line =~ /^.\s*\bstruct\s+spinlock\s+\w+\s*;/) {
+			WARN("USE_SPINLOCK_T",
+			     "struct spinlock should be spinlock_t\n" . $herecurr);
+		}
+
 # Check for misused memsets
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&