Re: [PATCH] Staging: Octeon Ethernet: Fix memory allocation.

[David Daney <ddaney@caviumnetworks.com>]

Ralf Baechle wrote:
> On Wed, Jan 27, 2010 at 01:22:53PM -0800, David Daney wrote:
>
> > After aligning the blocks returned by kmalloc, we need to save the
> > original pointer so they can be correctly freed.
> >
> > There are no guarantees about the alignment of SKB data, so we need to
> > handle worst case alignment.
> >
> > Since right shifts over subtraction have no distributive property, we
> > need to fix the back pointer calculation.
> >
> > Signed-off-by: David Daney <ddaney@caviumnetworks.com>
> > ---
> >
> > The original in the linux-queue tree is broken as it assumes the
> > kmalloc returns aligned blocks.  This is not the case when slab
> > debugging is enabled.
> Queue updated - but shouldn't the magic numbers 128 rsp 256 all over this
> patch be replaced by L1_CACHE_SHIFT rsp 2 * L1_CACHE_SHIFT?
Although the cache line size and alignment happen to match the size and 
alignment used by the FPA, they are different things.  So Probably it 
could be a different symbolic constant with a value of 128.
David Daney