linux-kernel - Re: [PATCH v3] sound: pci: emu10k1: code refactoring and casting removal

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Message-ID: <s5hzjq7sv76.wl%tiwai@suse.de>
Date:	Thu, 17 Oct 2013 18:45:01 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	"Geyslan G. Bem" <geyslan@...il.com>
Cc:	Jaroslav Kysela <perex@...ex.cz>,
	Bill Pemberton <wfp5p@...ginia.edu>,
	alsa-devel@...a-project.org (moderated list:SOUND),
	linux-kernel@...r.kernel.org (open list)
Subject: Re: [PATCH v3] sound: pci: emu10k1: code refactoring and casting removal

At Thu, 17 Oct 2013 12:35:31 -0300,
Geyslan G. Bem wrote:
> 
> Partially restructures _snd_emu10k1_audigy_init_efx() and
> _snd_emu10k1_init_efx() functions.
> 
> Removes useless casting (void *) from value returned by kcalloc;
> see Documentation/CodingStyle, Chap 14.
> 
> Signed-off-by: Geyslan G. Bem <geyslan@...il.com>

This causes the compiler error.

sound/pci/emu10k1/emufx.c:1190:26: error: expected expression before ‘)’ token
  icode->gpr_map = (__user) kcalloc(512 + 256 + 256 + 2 * 1024,

So, the straight cast only with __user isn't possible.  It's a sort of
modifier (like "const"), and it must be always with the real type to
cast.

Please do the reasonable tests before submitting any patches.


thanks,

Takashi

> ---
>  sound/pci/emu10k1/emufx.c | 76 ++++++++++++++++++++++++++++-------------------
>  1 file changed, 45 insertions(+), 31 deletions(-)
> 
> diff --git a/sound/pci/emu10k1/emufx.c b/sound/pci/emu10k1/emufx.c
> index 0275209..6c45714 100644
> --- a/sound/pci/emu10k1/emufx.c
> +++ b/sound/pci/emu10k1/emufx.c
> @@ -1182,15 +1182,20 @@ static int _snd_emu10k1_audigy_init_efx(struct snd_emu10k1 *emu)
>  	u32 *gpr_map;
>  	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 ||
> -	    (controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
> -				sizeof(*controls), GFP_KERNEL)) == NULL) {
> -		err = -ENOMEM;
> -		goto __err;
> -	}
> +	err = -ENOMEM;
> +	icode = kzalloc(sizeof(*icode), GFP_KERNEL);
> +	if (!icode)
> +		return err;
> +
> +	icode->gpr_map = (__user) kcalloc(512 + 256 + 256 + 2 * 1024,
> +					  sizeof(u_int32_t), GFP_KERNEL);
> +	if (!icode->gpr_map)
> +		goto __err_gpr;
> +	controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
> +			   sizeof(*controls), GFP_KERNEL);
> +	if (!controls)
> +		goto __err_ctrls;
> +
>  	gpr_map = (u32 __force *)icode->gpr_map;
>  
>  	icode->tram_data_map = icode->gpr_map + 512;
> @@ -1741,12 +1746,12 @@ A_OP(icode, &ptr, iMAC0, A_GPR(var), A_GPR(var), A_GPR(vol), A_EXTIN(input))
>  	emu->support_tlv = 0; /* clear again */
>  	snd_leave_user(seg);
>  
> - __err:
> +__err:
>  	kfree(controls);
> -	if (icode != NULL) {
> -		kfree((void __force *)icode->gpr_map);
> -		kfree(icode);
> -	}
> +__err_ctrls:
> +	kfree((void __force *)icode->gpr_map);
> +__err_gpr:
> +	kfree(icode);
>  	return err;
>  }
>  
> @@ -1813,18 +1818,26 @@ static int _snd_emu10k1_init_efx(struct snd_emu10k1 *emu)
>  	u32 *gpr_map;
>  	mm_segment_t seg;
>  
> -	if ((icode = kzalloc(sizeof(*icode), GFP_KERNEL)) == NULL)
> -		return -ENOMEM;
> -	if ((icode->gpr_map = (u_int32_t __user *)
> -	     kcalloc(256 + 160 + 160 + 2 * 512, sizeof(u_int32_t),
> -		     GFP_KERNEL)) == NULL ||
> -            (controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
> -				sizeof(struct snd_emu10k1_fx8010_control_gpr),
> -				GFP_KERNEL)) == NULL ||
> -	    (ipcm = kzalloc(sizeof(*ipcm), GFP_KERNEL)) == NULL) {
> -		err = -ENOMEM;
> -		goto __err;
> -	}
> +	err = -ENOMEM;
> +	icode = kzalloc(sizeof(*icode), GFP_KERNEL);
> +	if (!icode)
> +		return err;
> +
> +	icode->gpr_map = (__user) kcalloc(256 + 160 + 160 + 2 * 512,
> +					  sizeof(u_int32_t), GFP_KERNEL);
> +	if (!icode->gpr_map)
> +		goto __err_gpr;
> +
> +	controls = kcalloc(SND_EMU10K1_GPR_CONTROLS,
> +			   sizeof(struct snd_emu10k1_fx8010_control_gpr),
> +			   GFP_KERNEL);
> +	if (!controls)
> +		goto __err_ctrls;
> +
> +	ipcm = kzalloc(sizeof(*ipcm), GFP_KERNEL);
> +	if (!ipcm)
> +		goto __err_ipcm;
> +
>  	gpr_map = (u32 __force *)icode->gpr_map;
>  
>  	icode->tram_data_map = icode->gpr_map + 256;
> @@ -2363,13 +2376,14 @@ static int _snd_emu10k1_init_efx(struct snd_emu10k1 *emu)
>  	snd_leave_user(seg);
>  	if (err >= 0)
>  		err = snd_emu10k1_ipcm_poke(emu, ipcm);
> -      __err:
> +__err:
>  	kfree(ipcm);
> +__err_ipcm:
>  	kfree(controls);
> -	if (icode != NULL) {
> -		kfree((void __force *)icode->gpr_map);
> -		kfree(icode);
> -	}
> +__err_ctrls:
> +	kfree((void __force *)icode->gpr_map);
> +__err_gpr:
> +	kfree(icode);
>  	return err;
>  }
>  
> -- 
> 1.8.4
> 
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