Avoid matching allocs that appear to be known
small multiplications of a sizeof with a constant
because gcc as of 4.8 cannot optimize the code in
a calloc() exactly the same way as an alloc().
Look for numeric constants or what appear to be
upper case only macro #defines.
Signed-off-by: Joe Perches <j...@perches.com>
Noticed-by: Theodore Ts'o <ty...@mit.edu>
Original-patch-by: Fabian Frederick <f...@skynet.be>
---
scripts/checkpatch.pl | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 6c7cbaf..e0d0ead 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4486,22 +4486,23 @@ sub process {
# check for k[mz]alloc with multiplies that could be kmalloc_array/kcalloc
if ($^V && $^V ge 5.10.0 &&
- $line =~
/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/)
{
+ $line =~
/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)\s*,/)
{
my $oldfunc = $3;
my $a1 = $4;
my $a2 = $10;
my $newfunc = "kmalloc_array";
$newfunc = "kcalloc" if ($oldfunc eq "kzalloc");
- if ($a1 =~ /^sizeof\s*\S/ || $a2 =~ /^sizeof\s*\S/) {
+ my $r1 = $a1;
+ my $r2 = $a2;
+ if ($a1 =~ /^sizeof\s*\S/) {
+ $r1 = $a2;
+ $r2 = $a1;
+ }
+ if ($r1 !~ /^sizeof\b/ && $r2 =~ /^sizeof\s*\S/ &&
+ !($r1 =~ /^$Constant$/ || $r1 =~
/^[A-Z_][A-Z0-9_]*$/)) {
if (WARN("ALLOC_WITH_MULTIPLY",
"Prefer $newfunc over $oldfunc with
multiply\n" . $herecurr) &&
$fix) {
- my $r1 = $a1;
- my $r2 = $a2;
- if ($a1 =~ /^sizeof\s*\S/) {
- $r1 = $a2;
- $r2 = $a1;
- }
$fixed[$linenr - 1] =~
s/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*(k[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/$1
. ' = ' . "$newfunc(" . trim($r1) . ', ' . trim($r2)/e;
}
--
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