checkpatch: add --strict preference for p = kmalloc(sizeof(*p)...

Add another test for memory allocation style to follow
Documentation/CodingStyle:

		Chapter 14: Allocating memory

The preferred form for passing a size of a struct is the following:

	p = kmalloc(sizeof(*p), ...);

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 517da26d9a2d..6185eb67df94 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3507,6 +3507,14 @@ sub process {
                              "unnecessary cast may hide bugs, see http://c-faq.com/malloc/mallocnocast.html\n" . $herecurr);
                 }
 
+# alloc style
+# p = alloc(sizeof(struct foo), ...) should be p = alloc(sizeof(*p), ...)
+                if ($^V && $^V ge 5.10.0 &&
+                    $line =~ /\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*([kv][mz]alloc(?:_node)?)\s*\(\s*(sizeof\s*\(\s*struct\s+$Lval\s*\))/) {
+                        CHK("ALLOC_SIZEOF_STRUCT",
+                            "Prefer $3(sizeof(*$1)...) over $3($4...)\n" . $herecurr);
+                }
+
 # check for krealloc arg reuse
                 if ($^V && $^V ge 5.10.0 &&
                     $line =~ /\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*krealloc\s*\(\s*\1\s*,/) {