RE: [EXT] [PATCH] app/test-crypto-perf: fix invalid mbuf next operation

[Anoob Joseph <anoobj@marvell.com>]

Hi Suanming,

Good catch. Please see inline.

Thanks,
Anoob

> -----Original Message-----
> From: Suanming Mou <suanmingm@nvidia.com>
> Sent: Wednesday, January 3, 2024 9:24 AM
> To: Ciara Power <ciara.power@intel.com>
> Cc: dev@dpdk.org
> Subject: [EXT] [PATCH] app/test-crypto-perf: fix invalid mbuf next operation
> 
> External Email
> 
> ----------------------------------------------------------------------
> In fill_multi_seg_mbuf(), when remaining_segments is 0, rte_mbuf m's next
> should pointer to NULL instead of a new rte_mbuf, that casues setting m->next
> as NULL out of the while loop to the invalid mbuf.
> 
> This commit fixes the invalid mbuf next operation.
> 
> Fixes: bf9d6702eca9 ("app/crypto-perf: use single mempool")
> 
> Signed-off-by: Suanming Mou <suanmingm@nvidia.com>
> ---
>  app/test-crypto-perf/cperf_test_common.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/app/test-crypto-perf/cperf_test_common.c b/app/test-crypto-
> perf/cperf_test_common.c
> index 932aab16df..ad2076dd2e 100644
> --- a/app/test-crypto-perf/cperf_test_common.c
> +++ b/app/test-crypto-perf/cperf_test_common.c
> @@ -72,13 +72,15 @@ fill_multi_seg_mbuf(struct rte_mbuf *m, struct
> rte_mempool *mp,
>  		rte_mbuf_refcnt_set(m, 1);
>  		next_mbuf = (struct rte_mbuf *) ((uint8_t *) m +
>  					mbuf_hdr_size + segment_sz);
> -		m->next = next_mbuf;
> -		m = next_mbuf;
> -		remaining_segments--;
> 
> +		remaining_segments--;
> +		if (remaining_segments > 0) {

[Anoob] Would it make sense to move assignment of next_mbuf also to here? That way, the checks will become self explanatory.
  		next_mbuf = (struct rte_mbuf *) ((uint8_t *) m +
  					mbuf_hdr_size + segment_sz);

> +			m->next = next_mbuf;
> +			m = next_mbuf;
> +		} else {
> +			m->next = NULL;
> +		}
>  	} while (remaining_segments > 0);
> -
> -	m->next = NULL;
>  }
> 
>  static void
> --
> 2.34.1