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Date: Tue, 30 Jan 2024 10:05:36 -0800
From: Tyler Retzlaff <roretzla@linux.microsoft.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: Ferruh Yigit <ferruh.yigit@amd.com>, longli@microsoft.com,
 Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>, dev@dpdk.org
Subject: Re: [Patch v2] net/mana: use rte_pktmbuf_alloc_bulk for allocating
 RX WQEs
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On Tue, Jan 30, 2024 at 08:43:52AM -0800, Stephen Hemminger wrote:
> On Tue, 30 Jan 2024 10:19:32 +0000
> Ferruh Yigit <ferruh.yigit@amd.com> wrote:
> 
> > > -mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq)
> > > +mana_alloc_and_post_rx_wqes(struct mana_rxq *rxq, uint32_t count)
> > >  {
> > >  	int ret;
> > >  	uint32_t i;
> > > +	struct rte_mbuf **mbufs;
> > > +
> > > +	mbufs = rte_calloc_socket("mana_rx_mbufs", count, sizeof(struct rte_mbuf *),
> > > +				  0, rxq->mp->socket_id);
> > > +	if (!mbufs)
> > > +		return -ENOMEM;
> > >  
> > 
> > 'mbufs' is temporarily storage for allocated mbuf pointers, why not
> > allocate if from stack instead, can be faster and easier to manage:
> > "struct rte_mbuf *mbufs[count]"
> 
> That would introduce a variable length array.
> VLA's should be removed, they are not supported on Windows and many
> security tools flag them. The problem is that it makes the code brittle
> if count gets huge.

+1

> 
> But certainly regular calloc() or alloca() would work here.