| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 152/164] xprtrdma: Re-arm after missed events | Date | Wed, 2 Dec 2015 09:00:03 -0800 |
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3.19.8-ckt11 -stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever <chuck.lever@oracle.com>
commit 7b3d770c67bc07db5035999e4f864c5f2ff7b10e upstream.
ib_req_notify_cq(IB_CQ_REPORT_MISSED_EVENTS) returns a positive value if WCs were added to a CQ after the last completion upcall but before the CQ has been re-armed.
Commit 7f23f6f6e388 ("xprtrmda: Reduce lock contention in completion handlers") assumed that when ib_req_notify_cq() returned a positive RC, the CQ had also been successfully re-armed, making it safe to return control to the provider without losing any completion signals. That is an invalid assumption.
Change both completion handlers to continue polling while ib_req_notify_cq() returns a positive value.
Fixes: 7f23f6f6e388 ("xprtrmda: Reduce lock contention in ...") Signed-off-by: Chuck Lever <chuck.lever@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Devesh Sharma <devesh.sharma@avagotech.com> Tested-By: Devesh Sharma <devesh.sharma@avagotech.com> Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- net/sunrpc/xprtrdma/verbs.c | 66 +++++++-------------------------------------- 1 file changed, 10 insertions(+), 56 deletions(-)
diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index c98e406..6925e93 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -208,38 +208,17 @@ rpcrdma_sendcq_poll(struct ib_cq *cq, struct rpcrdma_ep *ep) return 0; } -/* - * Handle send, fast_reg_mr, and local_inv completions. - * - * Send events are typically suppressed and thus do not result - * in an upcall. Occasionally one is signaled, however. This - * prevents the provider's completion queue from wrapping and - * losing a completion. +/* Handle provider send completion upcalls. */ static void rpcrdma_sendcq_upcall(struct ib_cq *cq, void *cq_context) { struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_sendcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } - - rpcrdma_sendcq_poll(cq, ep); + do { + rpcrdma_sendcq_poll(cq, ep); + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | + IB_CQ_REPORT_MISSED_EVENTS) > 0); } static void @@ -304,42 +283,17 @@ out_schedule: return rc; } -/* - * Handle receive completions. - * - * It is reentrant but processes single events in order to maintain - * ordering of receives to keep server credits. - * - * It is the responsibility of the scheduled tasklet to return - * recv buffers to the pool. NOTE: this affects synchronization of - * connection shutdown. That is, the structures required for - * the completion of the reply handler must remain intact until - * all memory has been reclaimed. +/* Handle provider receive completion upcalls. */ static void rpcrdma_recvcq_upcall(struct ib_cq *cq, void *cq_context) { struct rpcrdma_ep *ep = (struct rpcrdma_ep *)cq_context; - int rc; - - rc = rpcrdma_recvcq_poll(cq, ep); - if (rc) { - dprintk("RPC: %s: ib_poll_cq failed: %i\n", - __func__, rc); - return; - } - rc = ib_req_notify_cq(cq, - IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS); - if (rc == 0) - return; - if (rc < 0) { - dprintk("RPC: %s: ib_req_notify_cq failed: %i\n", - __func__, rc); - return; - } - - rpcrdma_recvcq_poll(cq, ep); + do { + rpcrdma_recvcq_poll(cq, ep); + } while (ib_req_notify_cq(cq, IB_CQ_NEXT_COMP | + IB_CQ_REPORT_MISSED_EVENTS) > 0); } static void -- 1.9.1
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