Re: [PATCH] mbuf: rte_pktmbuf_alloc_bulk bugfix

[Olivier Matz <olivier.matz@6wind.com>]

Hi Gregory,

On Fri, 05 May 2017 16:29:59 +0300, Gregory Etelson <gregory@weka.io> wrote:
> bugfix in rte_pktmbuf_alloc_bulk
> 
> Signed-off-by: Gregory Etelson <gregory@weka.io>

Thank you for the fix. I suggest the following title instead:

mbuf: fix bulk allocation when debug enabled

Please refer to the guidelines:
http://dpdk.org/doc/guides/contributing/patches.html#commit-messages-subject-line

A description would have been welcome, for instance:

The debug assertions when allocating a raw mbuf are not correct since
commit 8f094a9ac5d7 ("mbuf: set mbuf fields while in pool"),
which triggers a panic when using this function in debug mode.

Change the expected number of segments to 1 instead of 0, and
factorize these sanity checks.


Fixes: 8f094a9ac5d7 ("mbuf: set mbuf fields while in pool")


Can you please submit a v2 with these changes? You can validate
your changes with checkpatches.sh and check-git-log.sh.

Thanks,
Olivier


> ---
>  lib/librte_mbuf/rte_mbuf.h | 24 +++++++++++-------------
>  1 file changed, 11 insertions(+), 13 deletions(-)
> 
> diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h
> index 466ec00..bebe94f 100644
> --- a/lib/librte_mbuf/rte_mbuf.h
> +++ b/lib/librte_mbuf/rte_mbuf.h
> @@ -788,6 +788,12 @@ rte_mbuf_refcnt_set(struct rte_mbuf *m, uint16_t new_value)
>  void
>  rte_mbuf_sanity_check(const struct rte_mbuf *m, int is_header);
>  
> +#define MBUF_RAW_ALLOC_CHECK(m_)				\
> +	RTE_ASSERT(rte_mbuf_refcnt_read(m_) == 1);	\
> +	RTE_ASSERT(m_->next == NULL);				\
> +	RTE_ASSERT(m_->nb_segs == 1);				\
> +	__rte_mbuf_sanity_check(m_, 0);
> +
>  /**
>   * Allocate an unitialized mbuf from mempool *mp*.
>   *
> @@ -815,11 +821,7 @@ static inline struct rte_mbuf *rte_mbuf_raw_alloc(struct rte_mempool *mp)
>  	if (rte_mempool_get(mp, &mb) < 0)
>  		return NULL;
>  	m = (struct rte_mbuf *)mb;
> -	RTE_ASSERT(rte_mbuf_refcnt_read(m) == 1);
> -	RTE_ASSERT(m->next == NULL);
> -	RTE_ASSERT(m->nb_segs == 1);
> -	__rte_mbuf_sanity_check(m, 0);
> -
> +	MBUF_RAW_ALLOC_CHECK(m);
>  	return m;
>  }
>  
> @@ -1152,23 +1154,19 @@ static inline int rte_pktmbuf_alloc_bulk(struct rte_mempool *pool,
>  	switch (count % 4) {
>  	case 0:
>  		while (idx != count) {
> -			RTE_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
> -			rte_mbuf_refcnt_set(mbufs[idx], 1);
> +			MBUF_RAW_ALLOC_CHECK(mbufs[idx]);
>  			rte_pktmbuf_reset(mbufs[idx]);
>  			idx++;
>  	case 3:
> -			RTE_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
> -			rte_mbuf_refcnt_set(mbufs[idx], 1);
> +			MBUF_RAW_ALLOC_CHECK(mbufs[idx]);
>  			rte_pktmbuf_reset(mbufs[idx]);
>  			idx++;
>  	case 2:
> -			RTE_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
> -			rte_mbuf_refcnt_set(mbufs[idx], 1);
> +			MBUF_RAW_ALLOC_CHECK(mbufs[idx]);
>  			rte_pktmbuf_reset(mbufs[idx]);
>  			idx++;
>  	case 1:
> -			RTE_ASSERT(rte_mbuf_refcnt_read(mbufs[idx]) == 0);
> -			rte_mbuf_refcnt_set(mbufs[idx], 1);
> +			MBUF_RAW_ALLOC_CHECK(mbufs[idx]);
>  			rte_pktmbuf_reset(mbufs[idx]);
>  			idx++;
>  		}