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From: Artem Bityutskiy <dedekind1@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: kernel-janitors@vger.kernel.org, linux-mtd@lists.infradead.org,
	Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [patch] UBIFS: use kmalloc_array() in recomp_data_node()
Date: Thu, 22 Nov 2012 11:26:43 +0000	[thread overview]
Message-ID: <1353583603.2701.45.camel@sauron.fi.intel.com> (raw)
In-Reply-To: <20121122111411.GJ6186@mwanda>

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On Thu, 2012-11-22 at 14:14 +0300, Dan Carpenter wrote:
> On Thu, Nov 22, 2012 at 12:31:37PM +0200, Artem Bityutskiy wrote:
> > On Sat, 2012-11-17 at 18:11 +0300, Dan Carpenter wrote:
> > >  	out_len = le32_to_cpu(dn->size);
> > > -	buf = kmalloc(out_len * WORST_COMPR_FACTOR, GFP_NOFS);
> > > +	buf = kmalloc_array(out_len, WORST_COMPR_FACTOR, GFP_NOFS);
> > >  	if (!buf)
> > >  		return -ENOMEM;
> > 
> > I think this makes the code unreadable, because we really allocate a
> > buffer, not an array.
> 
> The problem with the original code is that the multiply looks very
> suspect.  Everyone who reads it has to backtrack to find where
> dn->size is capped.
> 
> I guess in one sense we never allocate an array, we always declare
> it on the stack.  We debated the naming and there really isn't a
> good name.  kmalloc_safe() isn't right either.  But anyway, the
> intent is that eventually someone will right a coccinelle script
> which replaces all these allocations with kmalloc_array().

Did you consider kcalloc() ? Just like malloc() / calloc() libc
functions?

-- 
Best Regards,
Artem Bityutskiy

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WARNING: multiple messages have this Message-ID (diff)
From: Artem Bityutskiy <dedekind1@gmail.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: kernel-janitors@vger.kernel.org, linux-mtd@lists.infradead.org,
	Adrian Hunter <adrian.hunter@intel.com>
Subject: Re: [patch] UBIFS: use kmalloc_array() in recomp_data_node()
Date: Thu, 22 Nov 2012 13:26:43 +0200	[thread overview]
Message-ID: <1353583603.2701.45.camel@sauron.fi.intel.com> (raw)
In-Reply-To: <20121122111411.GJ6186@mwanda>

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On Thu, 2012-11-22 at 14:14 +0300, Dan Carpenter wrote:
> On Thu, Nov 22, 2012 at 12:31:37PM +0200, Artem Bityutskiy wrote:
> > On Sat, 2012-11-17 at 18:11 +0300, Dan Carpenter wrote:
> > >  	out_len = le32_to_cpu(dn->size);
> > > -	buf = kmalloc(out_len * WORST_COMPR_FACTOR, GFP_NOFS);
> > > +	buf = kmalloc_array(out_len, WORST_COMPR_FACTOR, GFP_NOFS);
> > >  	if (!buf)
> > >  		return -ENOMEM;
> > 
> > I think this makes the code unreadable, because we really allocate a
> > buffer, not an array.
> 
> The problem with the original code is that the multiply looks very
> suspect.  Everyone who reads it has to backtrack to find where
> dn->size is capped.
> 
> I guess in one sense we never allocate an array, we always declare
> it on the stack.  We debated the naming and there really isn't a
> good name.  kmalloc_safe() isn't right either.  But anyway, the
> intent is that eventually someone will right a coccinelle script
> which replaces all these allocations with kmalloc_array().

Did you consider kcalloc() ? Just like malloc() / calloc() libc
functions?

-- 
Best Regards,
Artem Bityutskiy

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  parent reply	other threads:[~2012-11-22 11:26 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-17 15:11 [patch] UBIFS: use kmalloc_array() in recomp_data_node() Dan Carpenter
2012-11-17 15:11 ` Dan Carpenter
2012-11-22 10:31 ` Artem Bityutskiy
2012-11-22 10:31   ` Artem Bityutskiy
2012-11-22 11:14   ` Dan Carpenter
2012-11-22 11:14     ` Dan Carpenter
2012-11-22 11:24     ` Artem Bityutskiy
2012-11-22 11:24       ` Artem Bityutskiy
2012-11-22 12:33       ` Dan Carpenter
2012-11-22 12:33         ` Dan Carpenter
2012-11-22 14:48         ` Artem Bityutskiy
2012-11-22 14:48           ` Artem Bityutskiy
2012-11-22 16:41           ` Dan Carpenter
2012-11-22 16:41             ` Dan Carpenter
2012-11-22 11:26     ` Artem Bityutskiy [this message]
2012-11-22 11:26       ` Artem Bityutskiy
2012-11-22 11:29       ` Artem Bityutskiy
2012-11-22 11:29         ` Artem Bityutskiy
2012-11-22 12:09         ` Dan Carpenter
2012-11-22 12:09           ` Dan Carpenter
2012-11-22 11:50       ` Dan Carpenter
2012-11-22 11:50         ` Dan Carpenter

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