Date: Tue, 14 Feb 2012 09:02:01 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
To: Dan Carpenter <dan.carpenter@oracle.com>
cc: Xi Wang <xi.wang@gmail.com>, Andrew Morton <akpm@linux-foundation.org>,
        Jesper Juhl <jj@chaosbits.net>, Jens Axboe <axboe@kernel.dk>,
        Pekka Enberg <penberg@kernel.org>, linux-kernel@vger.kernel.org,
        Matt Mackall <mpm@selenic.com>, David Rientjes <rientjes@google.com>
Subject: Re: [PATCH RFC v2] slab: introduce kmalloc_array
In-Reply-To: <20120214072017.GF26353@mwanda>
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On Tue, 14 Feb 2012, Dan Carpenter wrote:

> SAFE_ARRAY_SIZE() would return the size if there were no overflow
> and -1 on errors?  We can't return zero on errors because there are
> a lot of places which do zero size allocations and it's valid.  It
> seems ugly.

We could also catch these issues with BUG() or WARN_ON() and then return
zero.

> I really think that's over thinking things.  Let's just match
> kcalloc() exactly except without zeroing.  The BUILD_BUG_ON() thing
> is an over complication as well.  We haven't needed it for
> kcalloc().

The best thing is to remove kcalloc and get it all cleaned up
with some mechanism to safely calculate the size of an array to be
allocated.

The other way will lead to naming issues and then to a multiplication of
variants of the allocator interface. It makes things difficult to
understand and handle.

Keep it simple by providing a function that determines the array size and
handles any possible error condition.

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