Commit 4af7f7ff authored by Sagi Grimberg's avatar Sagi Grimberg Committed by Christoph Hellwig
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nvme-rdma: don't complete requests before a send work request has completed 



In order to guarantee that the HCA will never get an access violation
(either from invalidated rkey or from iommu) when retrying a send
operation we must complete a request only when both send completion and
the nvme cqe has arrived. We need to set the send/recv completions flags
atomically because we might have more than a single context accessing the
request concurrently (one is cq irq-poll context and the other is
user-polling used in IOCB_HIPRI).

Only then we are safe to invalidate the rkey (if needed), unmap the host
buffers, and complete the IO.

Signed-off-by: default avatarSagi Grimberg <sagi@grimberg.me>
Reviewed-by: default avatarMax Gurtovoy <maxg@mellanox.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent b4b591c8

drivers/nvme/host/rdma.c

+24 −4
Original line number Diff line number Diff line
@@ -59,6 +59,9 @@ struct nvme_rdma_request { 
	struct nvme_request	req;

	struct ib_mr		*mr;

	struct nvme_rdma_qe	sqe;

	union nvme_result	result;

	__le16			status;

	refcount_t		ref;

	struct ib_sge		sge[1 + NVME_RDMA_MAX_INLINE_SEGMENTS];

	u32			num_sge;

	int			nents;
@@ -1162,6 +1165,7 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue, 
	req->num_sge = 1;

	req->inline_data = false;

	req->mr->need_inval = false;

	refcount_set(&req->ref, 2); /* send and recv completions */



	c->common.flags |= NVME_CMD_SGL_METABUF;
@@ -1198,8 +1202,19 @@ static int nvme_rdma_map_data(struct nvme_rdma_queue *queue, 


static void nvme_rdma_send_done(struct ib_cq *cq, struct ib_wc *wc)

{

	if (unlikely(wc->status != IB_WC_SUCCESS))

	struct nvme_rdma_qe *qe =

		container_of(wc->wr_cqe, struct nvme_rdma_qe, cqe);

	struct nvme_rdma_request *req =

		container_of(qe, struct nvme_rdma_request, sqe);

	struct request *rq = blk_mq_rq_from_pdu(req);



	if (unlikely(wc->status != IB_WC_SUCCESS)) {

		nvme_rdma_wr_error(cq, wc, "SEND");

		return;

	}



	if (refcount_dec_and_test(&req->ref))

		nvme_end_request(rq, req->status, req->result);

}



static int nvme_rdma_post_send(struct nvme_rdma_queue *queue,
@@ -1318,14 +1333,19 @@ static int nvme_rdma_process_nvme_rsp(struct nvme_rdma_queue *queue, 
	}

	req = blk_mq_rq_to_pdu(rq);



	if (rq->tag == tag)

		ret = 1;

	req->status = cqe->status;

	req->result = cqe->result;



	if ((wc->wc_flags & IB_WC_WITH_INVALIDATE) &&

	    wc->ex.invalidate_rkey == req->mr->rkey)

		req->mr->need_inval = false;



	nvme_end_request(rq, cqe->status, cqe->result);

	if (refcount_dec_and_test(&req->ref)) {

		if (rq->tag == tag)

			ret = 1;

		nvme_end_request(rq, req->status, req->result);

	}



	return ret;

}

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