checkpatch: suggest using ether_addr_equal*()

Check if memcmp() is used to compare ethernet addresses and suggest using
ether_addr_equal() or ether_addr_equal_unaligned()

Signed-off-by: Mateusz Kulikowski <mateusz.kulikowski@gmail.com>
Acked-by: Joe Perches <joe@perches.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

scripts/checkpatch.pl

@@ -5157,6 +5157,14 @@ sub process {
 			}
 		}
 
+# Check for memcmp(foo, bar, ETH_ALEN) that could be ether_addr_equal*(foo, bar)
+		if ($^V && $^V ge 5.10.0 &&
+		    defined $stat &&
+		    $stat =~ /^\+(?:.*?)\bmemcmp\s*\(\s*$FuncArg\s*,\s*$FuncArg\s*\,\s*ETH_ALEN\s*\)/) {
+			WARN("PREFER_ETHER_ADDR_EQUAL",
+			     "Prefer ether_addr_equal() or ether_addr_equal_unaligned() over memcmp()\n" . "$here\n$stat\n")
+		}
+
 # typecasts on min/max could be min_t/max_t
 		if ($^V && $^V ge 5.10.0 &&
 		    defined $stat &&