Re: [PATCH] ALSA: emu10k1: casting (void *) value returned bykcalloc is useless

From: Joe Perches
Date: Thu Sep 05 2013 - 02:12:54 EST


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;



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