From: Joe Perches <joe@perches.com>
To: Duan Jiong <duanj.fnst@cn.fujitsu.com>
Cc: perex@perex.cz, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: emu10k1: casting (void *) value returned by kcalloc is useless
Date: Thu, 05 Sep 2013 03:18:57 -0700 [thread overview]
Message-ID: <1378376337.1944.26.camel@joe-AO722> (raw)
In-Reply-To: <5228589C.2060508@cn.fujitsu.com>
On Thu, 2013-09-05 at 18:10 +0800, Duan Jiong wrote:
> 于 2013年09月05日 14:12, Joe Perches 写道:
> > On Thu, 2013-09-05 at 13:57 +0800, Duan Jiong wrote:
> >> From: Duan Jiong <duanj.fnst@cn.fujitsu.com>
> >>
> >> 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.
I think your suggested patch causes sparse errors when
compiled with "$ make C=2 sound/pci/emu10k1/emufx.o"
And sorry, I just typed my reply in the email client and
I didn't compiled it or anything.
Most likely my suggestion needs a semicolon after the kzalloc
and (__user void *) on the kcalloc cast.
cheers, Joe
prev parent reply other threads:[~2013-09-05 10:19 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-05 5:57 [PATCH] ALSA: emu10k1: casting (void *) value returned by kcalloc is useless Duan Jiong
2013-09-05 6:12 ` Joe Perches
2013-09-05 10:10 ` Duan Jiong
2013-09-05 10:18 ` Joe Perches [this message]
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