linux-kernel - Re: [PATCH] ext4: hash: change kzalloc(n * sizeof, ...) to kcalloc(n, sizeof, ...)

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Message-ID: <Z9ZFabmQuSLiwfE5@casper.infradead.org>
Date: Sun, 16 Mar 2025 03:28:41 +0000
From: Matthew Wilcox <willy@...radead.org>
To: Ethan Carter Edwards <ethan@...ancedwards.com>
Cc: Theodore Ts'o <tytso@....edu>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, linux-hardening@...r.kernel.org
Subject: Re: [PATCH] ext4: hash: change kzalloc(n * sizeof, ...) to
 kcalloc(n, sizeof, ...)

On Sat, Mar 15, 2025 at 12:29:34PM -0400, Ethan Carter Edwards wrote:
> Open coded arithmetic in allocator arguments is discouraged. Helper
> functions like kcalloc are preferred.

Well, yes, but ...

> +++ b/fs/ext4/hash.c
> @@ -302,7 +302,7 @@ int ext4fs_dirhash(const struct inode *dir, const char *name, int len,
>  
>  	if (len && IS_CASEFOLDED(dir) &&
>  	   (!IS_ENCRYPTED(dir) || fscrypt_has_encryption_key(dir))) {
> -		buff = kzalloc(sizeof(char) * PATH_MAX, GFP_KERNEL);
> +		buff = kcalloc(PATH_MAX, sizeof(char), GFP_KERNEL);

sizeof(char) is defined to be 1.  So this should just be
kzalloc(PATH_MAX, GFP_KERNEL).