From: Gal Pressman <galpress@amazon.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: Doug Ledford <dledford@redhat.com>, <linux-rdma@vger.kernel.org>,
Alexander Matushevsky <matua@amazon.com>,
Firas JahJah <firasj@amazon.com>,
Yossi Leybovich <sleybo@amazon.com>
Subject: Re: [PATCH for-next 4/4] RDMA/efa: CQ notifications
Date: Wed, 1 Sep 2021 14:50:42 +0300 [thread overview]
Message-ID: <7a4963ea-f028-e787-a5ba-fabf907c6d6b@amazon.com> (raw)
In-Reply-To: <20210820182702.GA550455@nvidia.com>
On 20/08/2021 21:27, Jason Gunthorpe wrote:
> On Wed, Aug 11, 2021 at 06:11:31PM +0300, Gal Pressman wrote:
>> diff --git a/drivers/infiniband/hw/efa/efa_main.c b/drivers/infiniband/hw/efa/efa_main.c
>> index 417dea5f90cf..29db4dec02f0 100644
>> +++ b/drivers/infiniband/hw/efa/efa_main.c
>> @@ -67,6 +67,46 @@ static void efa_release_bars(struct efa_dev *dev, int bars_mask)
>> pci_release_selected_regions(pdev, release_bars);
>> }
>>
>> +static void efa_process_comp_eqe(struct efa_dev *dev, struct efa_admin_eqe *eqe)
>> +{
>> + u16 cqn = eqe->u.comp_event.cqn;
>> + struct efa_cq *cq;
>> +
>> + cq = xa_load(&dev->cqs_xa, cqn);
>> + if (unlikely(!cq)) {
>
> This seems unlikely to be correct, what prevents cq from being
> destroyed concurrently?
>
> A comp_handler cannot be running after cq destroy completes.
Sorry for the long turnaround, was OOO.
The CQ cannot be destroyed until all completion events are acked.
https://github.com/linux-rdma/rdma-core/blob/7fd01f0c6799f0ecb99cae03c22cf7ff61ffbf5a/libibverbs/man/ibv_get_cq_event.3#L45
https://github.com/linux-rdma/rdma-core/blob/7fd01f0c6799f0ecb99cae03c22cf7ff61ffbf5a/libibverbs/cmd_cq.c#L208
>> @@ -421,6 +551,7 @@ static struct efa_dev *efa_probe_device(struct pci_dev *pdev)
>> edev->efa_dev = dev;
>> edev->dmadev = &pdev->dev;
>> dev->pdev = pdev;
>> + xa_init_flags(&dev->cqs_xa, XA_FLAGS_LOCK_IRQ);
>
> And this is confusing too, since the above is the only reference and
> doesn't take the xa_lock why does the xa need to use LOCK_IRQ?
Oh, I'm now noticing that the load operation uses an rcu lock, not the xa_lock..
This can be replaced with xa_init().
Thanks for the review.
next prev parent reply other threads:[~2021-09-01 11:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-11 15:11 [PATCH for-next 0/4] EFA CQ notifications Gal Pressman
2021-08-11 15:11 ` [PATCH for-next 1/4] RDMA/efa: Free IRQ vectors on error flow Gal Pressman
2021-08-20 18:34 ` Jason Gunthorpe
2021-08-11 15:11 ` [PATCH for-next 2/4] RDMA/efa: Remove unused cpu field from irq struct Gal Pressman
2021-08-11 15:11 ` [PATCH for-next 3/4] RDMA/efa: Rename vector field in efa_irq struct to irqn Gal Pressman
2021-08-11 15:11 ` [PATCH for-next 4/4] RDMA/efa: CQ notifications Gal Pressman
2021-08-20 18:27 ` Jason Gunthorpe
2021-09-01 11:50 ` Gal Pressman [this message]
2021-09-01 11:57 ` Jason Gunthorpe
2021-09-01 14:24 ` Gal Pressman
2021-09-01 15:36 ` Jason Gunthorpe
2021-09-02 7:03 ` Gal Pressman
2021-09-02 13:02 ` Jason Gunthorpe
2021-09-02 15:09 ` Gal Pressman
2021-09-02 15:10 ` Jason Gunthorpe
2021-09-02 15:17 ` Gal Pressman
2021-09-02 15:41 ` Jason Gunthorpe
2021-09-05 7:25 ` Gal Pressman
2021-09-05 7:59 ` Leon Romanovsky
2021-09-05 10:45 ` Gal Pressman
2021-09-05 10:54 ` Leon Romanovsky
2021-09-05 11:05 ` Gal Pressman
2021-09-05 13:14 ` Leon Romanovsky
2021-09-05 14:36 ` Gal Pressman
2021-09-07 11:31 ` Jason Gunthorpe
2021-09-09 11:00 ` Gal Pressman
2021-08-20 18:36 ` [PATCH for-next 0/4] EFA " Jason Gunthorpe
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