Re: [PATCH v3 rdma-next] RDMA/qedr: SRQ's bug fixes

From: Jason Gunthorpe <jgg@nvidia.com>
To: Yuval Basson <ybason@marvell.com>
Cc: <dledford@redhat.com>, <linux-rdma@vger.kernel.org>,
	Michal Kalderon <mkalderon@marvell.com>
Subject: Re: [PATCH v3 rdma-next] RDMA/qedr: SRQ's bug fixes
Date: Thu, 16 Jul 2020 14:59:07 -0300	[thread overview]
Message-ID: <20200716175907.GA2653867@nvidia.com> (raw)
In-Reply-To: <20200708195526.31040-1-ybason@marvell.com>

On Wed, Jul 08, 2020 at 10:55:26PM +0300, Yuval Basson wrote:
> QP's with the same SRQ, working on different CQs and running in parallel
> on different CPUs could lead to a race when maintaining the SRQ consumer
> count, and leads to FW running out of SRQs. Update the consumer atomically.
> Make sure the wqe_prod is updated after the sge_prod due to FW
> requirements.
> 
> Fixes: 3491c9e799fb9 ("RDMA/qedr: Add support for kernel mode SRQ's")
> Signed-off-by: Michal Kalderon <mkalderon@marvell.com>
> Signed-off-by: Yuval Basson <ybason@marvell.com>
> ---
> Change in v3:
>  *Replace changelog
> 
> Changes in v2:
> * Change barrier() to dma_wmb()
> * Remove redundant dma_wmb()
> 
>  drivers/infiniband/hw/qedr/qedr.h  |  4 ++--
>  drivers/infiniband/hw/qedr/verbs.c | 23 +++++++++++------------
>  2 files changed, 13 insertions(+), 14 deletions(-)

Applied to for-next, thanks

> diff --git a/drivers/infiniband/hw/qedr/verbs.c b/drivers/infiniband/hw/qedr/verbs.c
> index 9b9e802..444537b 100644
> --- a/drivers/infiniband/hw/qedr/verbs.c
> +++ b/drivers/infiniband/hw/qedr/verbs.c
> @@ -1510,6 +1510,7 @@ int qedr_create_srq(struct ib_srq *ibsrq, struct ib_srq_init_attr *init_attr,
>  	srq->dev = dev;
>  	hw_srq = &srq->hw_srq;
>  	spin_lock_init(&srq->lock);
> +	atomic_set(&hw_srq->wr_cons_cnt, 0);

I deleted this though, it is redundant the memory is pre-zero'd by the
core code.

Jason