linux-kernel - Re: [PATCH] parisc: Increase the usage check of kmalloc allocated object a

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Message-ID: <f346579c-e6a3-d2bb-1c21-d914aeb9a77d@gmx.de>
Date:   Wed, 14 Sep 2022 08:18:19 +0200
From:   Helge Deller <deller@....de>
To:     Li zeming <zeming@...china.com>,
        James.Bottomley@...senPartnership.com
Cc:     linux-parisc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] parisc: Increase the usage check of kmalloc allocated
 object a

On 9/14/22 08:04, Li zeming wrote:
> In the case of memory allocation failure, no alignment operation is
> required.
>
> Signed-off-by: Li zeming <zeming@...china.com>
> ---
>   drivers/parisc/iosapic.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/parisc/iosapic.c b/drivers/parisc/iosapic.c
> index 3a8c98615634..33de438916d3 100644
> --- a/drivers/parisc/iosapic.c
> +++ b/drivers/parisc/iosapic.c
> @@ -229,7 +229,9 @@ static struct irt_entry *iosapic_alloc_irt(int num_entries)
>   	 * 4-byte alignment on 32-bit kernels
>   	 */
>   	a = (unsigned long)kmalloc(sizeof(struct irt_entry) * num_entries + 8, GFP_KERNEL);
> -	a = (a + 7UL) & ~7UL;
> +	if (a)
> +		a = (a + 7UL) & ~7UL;
> +

As you said, the adjustment isn't required, but it's still ok.
So I think the additional "if" isn't necessary and so I'm not
applying your patch.

Anyway, thanks for your help to try to improve the code!

Helge


>   	return (struct irt_entry *)a;
>   }
>