Re: [dpdk-dev] [PATCH] net/mlx5: fix incorrect r/w lock usage in DMA unmap

[Slava Ovsiienko <viacheslavo@nvidia.com>]

Hi, Feifei

Sorry for the delayed review.
I think it is a good catch, thank you for the patch.

Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>

With best regards,
Slava

> -----Original Message-----
> From: Feifei Wang <Feifei.Wang2@arm.com>
> Sent: Tuesday, June 22, 2021 4:54
> To: Feifei Wang <Feifei.Wang2@arm.com>; Matan Azrad
> <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>; Slava Ovsiienko
> <viacheslavo@nvidia.com>
> Cc: dev@dpdk.org; nd <nd@arm.com>; Shahaf Shuler <shahafs@nvidia.com>;
> stable@dpdk.org; Ruifeng Wang <Ruifeng.Wang@arm.com>; nd
> <nd@arm.com>
> Subject: 回复: [PATCH] net/mlx5: fix incorrect r/w lock usage in DMA unmap
> 
> Hi, Slava
> 
> Would you please help review this patch?
> Thanks.
> 
> Best Regards
> Feifei
> 
> > -----邮件原件-----
> > 发件人: Feifei Wang <feifei.wang2@arm.com>
> > 发送时间: 2021年5月27日 17:48
> > 收件人: Matan Azrad <matan@nvidia.com>; Shahaf Shuler
> > <shahafs@nvidia.com>; Viacheslav Ovsiienko <viacheslavo@nvidia.com>
> > 抄送: dev@dpdk.org; nd <nd@arm.com>; Feifei Wang
> <Feifei.Wang2@arm.com>;
> > shahafs@mellanox.com; stable@dpdk.org; Ruifeng Wang
> > <Ruifeng.Wang@arm.com>
> > 主题: [PATCH] net/mlx5: fix incorrect r/w lock usage in DMA unmap
> >
> > For mlx5 DMA unmap, write lock should be used for rebuilding memory
> > region cache table rather than read lock.
> >
> > Fixes: 989e999d9305 ("net/mlx5: support PCI device DMA map and unmap")
> > Cc: shahafs@mellanox.com
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Feifei Wang <feifei.wang2@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> > ---
> >  drivers/net/mlx5/mlx5_mr.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_mr.c b/drivers/net/mlx5/mlx5_mr.c
> > index
> > e791b6338d..45a122f4f9 100644
> > --- a/drivers/net/mlx5/mlx5_mr.c
> > +++ b/drivers/net/mlx5/mlx5_mr.c
> > @@ -395,10 +395,10 @@ mlx5_dma_unmap(struct rte_pci_device *pdev,
> void
> > *addr,
> >  	}
> >  	priv = dev->data->dev_private;
> >  	sh = priv->sh;
> > -	rte_rwlock_read_lock(&sh->share_cache.rwlock);
> > +	rte_rwlock_write_lock(&sh->share_cache.rwlock);
> >  	mr = mlx5_mr_lookup_list(&sh->share_cache, &entry,
> (uintptr_t)addr);
> >  	if (!mr) {
> > -		rte_rwlock_read_unlock(&sh->share_cache.rwlock);
> > +		rte_rwlock_write_unlock(&sh->share_cache.rwlock);
> >  		DRV_LOG(WARNING, "address 0x%" PRIxPTR " wasn't
> registered "
> >  				 "to PCI device %p", (uintptr_t)addr,
> >  				 (void *)pdev);
> > @@ -423,7 +423,7 @@ mlx5_dma_unmap(struct rte_pci_device *pdev, void
> > *addr,
> >  	DRV_LOG(DEBUG, "broadcasting local cache flush, gen=%d",
> >  	      sh->share_cache.dev_gen);
> >  	rte_smp_wmb();
> > -	rte_rwlock_read_unlock(&sh->share_cache.rwlock);
> > +	rte_rwlock_write_unlock(&sh->share_cache.rwlock);
> >  	return 0;
> >  }
> >
> > --
> > 2.25.1