checkpatch: check for common memset parameter issues against statments

Move the memset checks over to work against the statement.  Also add
checks for 0 and 1 used as lengths.  Generally these indicate badly
ordered parameters.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Cc: 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, 22 insertions, 6 deletions

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 06e22caa5692..8199d59d0ad7 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3120,6 +3120,28 @@ sub process {
                              "Avoid line continuations in quoted strings\n" . $herecurr);
                 }
 
+# Check for misused memsets
+                if (defined $stat && $stat =~ /\bmemset\s*\((.*)\)/s) {
+                        my $args = $1;
+
+                        # Flatten any parentheses and braces
+                        while ($args =~ s/\([^\(\)]*\)/10/s ||
+                               $args =~ s/\{[^\{\}]*\}/10/s ||
+                               $args =~ s/\[[^\[\]]*\]/10/s)
+                        {
+                        }
+                        # Extract the simplified arguments.
+                        my ($ms_addr, $ms_val, $ms_size) =
+                                                split(/\s*,\s*/, $args);
+                        if ($ms_size =~ /^(0x|)0$/i) {
+                                ERROR("MEMSET",
+                                      "memset size is 3rd argument, not the second.\n" . $herecurr);
+                        } elsif ($ms_size =~ /^(0x|)1$/i) {
+                                WARN("MEMSET",
+                                     "single byte memset is suspicious. Swapped 2nd/3rd argument?\n" . $herecurr);
+                        }
+                }
+
 # check for new externs in .c files.
                 if ($realfile =~ /\.c$/ && defined $stat &&
                     $stat =~ /^.\s*(?:extern\s+)?$Type\s+($Ident)(\s*)\(/s)
@@ -3291,12 +3313,6 @@ sub process {
                         WARN("EXPORTED_WORLD_WRITABLE",
                              "Exporting world writable files is usually an error. Consider more restrictive permissions.\n" . $herecurr);
                 }
-
-                # Check for memset with swapped arguments
-                if ($line =~ /memset.*\,(\ |)(0x|)0(\ |0|)\);/) {
-                        ERROR("MEMSET",
-                              "memset size is 3rd argument, not the second.\n" . $herecurr);
-                }
         }
 
         # If we have no input at all, then there is nothing to report on