This is a note to let you know that I've just added the patch titled

nvme-rdma: don't complete requests before a send work request has completed

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: nvme-rdma-don-t-complete-requests-before-a-send-work-request-has-completed.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 13:45:42 CET 2018

From: Sagi Grimberg sagi@grimberg.me Date: Thu, 23 Nov 2017 17:35:22 +0200 Subject: nvme-rdma: don't complete requests before a send work request has completed

From: Sagi Grimberg sagi@grimberg.me

[ Upstream commit 4af7f7ff92a42b6c713293c99e7982bcfcf51a70 ]

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: Sagi Grimberg sagi@grimberg.me Reviewed-by: Max Gurtovoy maxg@mellanox.com Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/nvme/host/rdma.c | 28 ++++++++++++++++++++++++---- 1 file changed, 24 insertions(+), 4 deletions(-)

--- a/drivers/nvme/host/rdma.c +++ b/drivers/nvme/host/rdma.c @@ -67,6 +67,9 @@ 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; @@ -1177,6 +1180,7 @@ static int nvme_rdma_map_data(struct nvm 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;

@@ -1213,8 +1217,19 @@ static int nvme_rdma_map_data(struct nvm

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); }

/* @@ -1359,14 +1374,19 @@ static int nvme_rdma_process_nvme_rsp(st } 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; }

Patches currently in stable-queue which might be from sagi@grimberg.me are

queue-4.14/nvmet-fc-correct-ref-counting-error-when-deferred-rcv-used.patch queue-4.14/nvme-fabrics-introduce-init-command-check-for-a-queue-that-is-not-alive.patch queue-4.14/nvme-fc-check-if-queue-is-ready-in-queue_rq.patch queue-4.14/nvme-loop-check-if-queue-is-ready-in-queue_rq.patch queue-4.14/nvme-rdma-don-t-complete-requests-before-a-send-work-request-has-completed.patch