brain-hackers_pepepper-mirror
/
linux-brain
mirror of https://github.com/brain-hackers/linux-brain.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

checkpatch: emit fewer kmalloc_array/kcalloc conversion warnings 

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 <joe@perches.com>
Reported-by: Theodore Ts'o <tytso@mit.edu>
Original-patch-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joe Perches 2014-08-06 16:10:55 -07:00 committed by Linus Torvalds
parent f27c95db11
commit e367455a9f
1 changed files with 9 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
scripts/checkpatch.pl
View File

@ -4487,22 +4487,23 @@ 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;
}