Re: [patch] UBIFS: use kmalloc_array() in recomp_data_node()

Dan Carpenter
2012-11-22T11:50:05Z

On Thu, Nov 22, 2012 at 01:26:43PM +0200, Artem Bityutskiy wrote:
> 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?

We already have a kcalloc() but it zeroes out the memory.

regards,
dan carpenter