linux-kernel - [PATCH V2 2/2] checkpatch: Add a couple new alloc functions to alloc with multiplies check

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Date:   Wed, 13 Sep 2023 18:41:47 -0700
From:   Joe Perches <joe@...ches.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Andy Whitcroft <apw@...onical.com>,
        Dwaipayan Ray <dwaipayanray1@...il.com>,
        Lukas Bulwahn <lukas.bulwahn@...il.com>
Cc:     "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: [PATCH V2 2/2] checkpatch: Add a couple new alloc functions to alloc with multiplies check

vmalloc() and vzalloc() functions have now 2-factor multiplication
argument forms vmalloc_array() and vcalloc(), correspondingly.

Add alloc-with-multiplies checks for these new functions.

Simplify the original codes repeated else to use a hash.

Link: https://github.com/KSPP/linux/issues/342

Original-patch-by: Gustavo A. R. Silva <gustavoars@...nel.org>
Co-developed-by: Gustavo A. R. Silva <gustavoars@...nel.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>
Link: https://lore.kernel.org/lkml/ZQCaO+tYycDxVLy7@work/
Signed-off-by: Joe Perches <joe@...ches.com>
---

v2: Fix search because vmalloc functions don't take a 3rd argument

 scripts/checkpatch.pl | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 617f9e53bacdf..4cb248985eefc 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -834,6 +834,16 @@ our %deprecated_apis = (
 #Create a search pattern for all these strings to speed up a loop below
 our $deprecated_apis_search = '(?:' . join('|', keys %deprecated_apis) . ')';
 
+our %alloc_with_multiply_apis = (
+	"kmalloc"		=> "kmalloc_array",
+	"kvmalloc"		=> "kvmalloc_array",
+	"vmalloc"		=> "vmalloc_array",
+	"kvzalloc"		=> "kvcalloc",
+	"kzalloc"		=> "kcalloc",
+	"vzalloc"		=> "vcalloc",
+);
+our $alloc_with_multiply_search = '(?:' . join('|', keys %alloc_with_multiply_apis) . ')';
+
 our $mode_perms_world_writable = qr{
 	S_IWUGO		|
 	S_IWOTH		|
@@ -7187,17 +7197,14 @@ sub process {
 			    "Prefer $3(sizeof(*$1)...) over $3($4...)\n" . $herecurr);
 		}
 
-# check for (kv|k)[mz]alloc with multiplies that could be kmalloc_array/kvmalloc_array/kvcalloc/kcalloc
+# check for various allocs with multiplies that should use safer functions
 		if ($perl_version_ok &&
 		    defined $stat &&
-		    $stat =~ /^\+\s*($Lval)\s*\=\s*(?:$balanced_parens)?\s*((?:kv|k)[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)\s*,/) {
+		    $stat =~ /^\+\s*($Lval)\s*\=\s*(?:$balanced_parens)?\s*($alloc_with_multiply_search)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/) {
 			my $oldfunc = $3;
+			my $newfunc = $alloc_with_multiply_apis{$oldfunc};
 			my $a1 = $4;
 			my $a2 = $10;
-			my $newfunc = "kmalloc_array";
-			$newfunc = "kvmalloc_array" if ($oldfunc eq "kvmalloc");
-			$newfunc = "kvcalloc" if ($oldfunc eq "kvzalloc");
-			$newfunc = "kcalloc" if ($oldfunc eq "kzalloc");
 			my $r1 = $a1;
 			my $r2 = $a2;
 			if ($a1 =~ /^sizeof\s*\S/) {
@@ -7213,7 +7220,7 @@ sub process {
 					 "Prefer $newfunc over $oldfunc with multiply\n" . $herectx) &&
 				    $cnt == 1 &&
 				    $fix) {
-					$fixed[$fixlinenr] =~ s/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*((?:kv|k)[mz]alloc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/$1 . ' = ' . "$newfunc(" . trim($r1) . ', ' . trim($r2)/e;
+					$fixed[$fixlinenr] =~ s/\b($Lval)\s*\=\s*(?:$balanced_parens)?\s*($oldfunc)\s*\(\s*($FuncArg)\s*\*\s*($FuncArg)/$1 . ' = ' . "$newfunc(" . trim($r1) . ', ' . trim($r2)/e;
 				}
 			}
 		}
-- 
2.41.0