Re: [PATCH for-next 4/4] RDMA/efa: CQ notifications
From: Jason Gunthorpe <jgg@nvidia.com>
Date: 2021-09-01 11:57:20
On Wed, Sep 01, 2021 at 02:50:42PM +0300, Gal Pressman wrote:
On 20/08/2021 21:27, Jason Gunthorpe wrote:quoted
On Wed, Aug 11, 2021 at 06:11:31PM +0300, Gal Pressman wrote:quoted
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
That is something quite different, and in userspace. What in the kernel prevents tha xa_load and the xa_erase from racing together? Jason