Re: [dpdk-dev] [PATCH] mempool: fix the inverted pg_num check on create

[Dan Aloni <dan@kernelim.com>]

On Mon, Aug 17, 2015 at 10:55:35AM +0200, Olivier MATZ wrote:
> On 08/16/2015 09:08 PM, Dan Aloni wrote:
[..]
> >  	/* Check that pg_num and pg_shift parameters are valid. */
> > -	if (pg_num < RTE_DIM(mp->elt_pa) || pg_shift > MEMPOOL_PG_SHIFT_MAX) {
> > +	if (pg_num > RTE_DIM(mp->elt_pa) || pg_shift > MEMPOOL_PG_SHIFT_MAX) {
> >  		rte_errno = EINVAL;
> >  		return NULL;

> 
> From what I see, RTE_DIM(mp->elt_pa) is always 1:
> 
> 	#define MEMPOOL_PG_NUM_DEFAULT  1
> 	struct rte_mempool {
> 		...
> 	        phys_addr_t elt_pa[MEMPOOL_PG_NUM_DEFAULT];
> 	}  __rte_cache_aligned;
> 
> From rte_mempool_xmem_create() documentation, pg_num gives the size of
> the paddr array, which is allocated by the caller. So I think there is
> no issue here.

You're right, I missed on the fact that mempool takes pg_num as its
run-time determined size of the array for both its dynamically allocated
copy and the caller's provided array.

The MEMPOOL_PG_NUM_DEFAULT macro is was a bit distracting in this. I
wanted to provide pg_num > 1 and it wasn't clear on whether to modify
the macro, or simply call the function :). So, never mind the patch.

-- 
Dan Aloni