Re: [PATCH] ALSA: emu10k1: casting (void *) value returned by kcallocis useless

From: Duan Jiong
Date: Thu Sep 05 2013 - 06:11:19 EST


ä 2013å09æ05æ 14:12, Joe Perches åé:
> On Thu, 2013-09-05 at 13:57 +0800, Duan Jiong wrote:
>> From: Duan Jiong <duanj.fnst@xxxxxxxxxxxxxx>
>>
>> Casting (void *) value returned by kcalloc is useless
>> as mentioned in Documentation/CodingStyle, Chap 14.
>
> __user is an important marker that is lost here.
>
>> diff --git a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
> []
>> @@ -1183,9 +1183,8 @@ static int _snd_emu10k1_audigy_init_efx(struct snd_emu10k1 *emu)
>> mm_segment_t seg;
>>
>> if ((icode = kzalloc(sizeof(*icode), GFP_KERNEL)) == NULL ||
>> - (icode->gpr_map = (u_int32_t __user *)
>> - kcalloc(512 + 256 + 256 + 2 * 1024, sizeof(u_int32_t),
>> - GFP_KERNEL)) == NULL ||
>> + (icode->gpr_map = kcalloc(512 + 256 + 256 + 2 * 1024,
>> + sizeof(u_int32_t), GFP_KERNEL)) == NULL ||
>> (controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
>> sizeof(*controls), GFP_KERNEL)) == NULL) {
>> err = -ENOMEM;
>
> I think this would be clearer as
>
> err = -ENOMEM;
> icode = kzalloc(sizeof(*icode), GFP_KERNEL)
> if (!icode)
> goto err;
> icode->gpr_map = (__user)kcalloc(512 + 256 + 256 + 2 * 1024,
> sizeof(u_int32_t), GFP_KERNEL);
> if (!icode->gpr_map)
> goto err;
> controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
> sizeof(*controls), GFP_KERNEL);
> if (!controls)
> goto err;
>

Maybe it should keep the original style, because i do as you said, and
error messages appear during compiling the kernel.

Thanks,
Duan

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