checkpatch: add rules to check init attribute and const defects

People get this regularly wrong and it breaks the LTO builds, as it causes
a section attribute conflict.

Add --fix capability too.

Based on a patch from Andi Kleen.

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

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 8489c35..23d55bf 100755 (executable)
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -241,8 +241,11 @@ our $Sparse        = qr{
                        __ref|
                        __rcu
                }x;
-
-our $InitAttribute = qr{__(?:mem|cpu|dev|net_|)(?:initdata|initconst|init\b)};
+our $InitAttributePrefix = qr{__(?:mem|cpu|dev|net_|)};
+our $InitAttributeData = qr{$InitAttributePrefix(?:initdata\b)};
+our $InitAttributeConst = qr{$InitAttributePrefix(?:initconst\b)};
+our $InitAttributeInit = qr{$InitAttributePrefix(?:init\b)};
+our $InitAttribute = qr{$InitAttributeData|$InitAttributeConst|$InitAttributeInit};
 
 # Notes to $Attribute:
 # We need \b after 'init' otherwise 'initconst' will cause a false positive in a check
@@ -3759,6 +3762,35 @@ sub process {
                        }
                }
 
+# check for $InitAttributeData (ie: __initdata) with const
+               if ($line =~ /\bconst\b/ && $line =~ /($InitAttributeData)/) {
+                       my $attr = $1;
+                       $attr =~ /($InitAttributePrefix)(.*)/;
+                       my $attr_prefix = $1;
+                       my $attr_type = $2;
+                       if (ERROR("INIT_ATTRIBUTE",
+                                 "Use of const init definition must use ${attr_prefix}initconst\n" . $herecurr) &&
+                           $fix) {
+                               $fixed[$linenr - 1] =~
+                                   s/$InitAttributeData/${attr_prefix}initconst/;
+                       }
+               }
+
+# check for $InitAttributeConst (ie: __initconst) without const
+               if ($line !~ /\bconst\b/ && $line =~ /($InitAttributeConst)/) {
+                       my $attr = $1;
+                       if (ERROR("INIT_ATTRIBUTE",
+                                 "Use of $attr requires a separate use of const\n" . $herecurr) &&
+                           $fix) {
+                               my $lead = $fixed[$linenr - 1] =~
+                                   /(^\+\s*(?:static\s+))/;
+                               $lead = rtrim($1);
+                               $lead = "$lead " if ($lead !~ /^\+$/);
+                               $lead = "${lead}const ";
+                               $fixed[$linenr - 1] =~ s/(^\+\s*(?:static\s+))/$lead/;
+                       }
+               }
+
 # prefer usleep_range over udelay
                if ($line =~ /\budelay\s*\(\s*(\d+)\s*\)/) {
                        # ignore udelay's < 10, however