From 9294000d6d895ad609f3cc4aff98c9c6175b466f Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 14 Feb 2017 10:56:36 -0800 Subject: [PATCH] IB/srp: Drain the send queue before destroying a QP A quote from the IB spec: However, if the Consumer does not wait for the Affiliated Asynchronous Last WQE Reached Event, then WQE and Data Segment leakage may occur. Therefore, it is good programming practice to tear down a QP that is associated with an SRQ by using the following process: * Put the QP in the Error State; * wait for the Affiliated Asynchronous Last WQE Reached Event; * either: * drain the CQ by invoking the Poll CQ verb and either wait for CQ to be empty or the number of Poll CQ operations has exceeded CQ capacity size; or * post another WR that completes on the same CQ and wait for this WR to return as a WC; * and then invoke a Destroy QP or Reset QP. Signed-off-by: Bart Van Assche Cc: Christoph Hellwig Cc: Israel Rukshin Cc: Max Gurtovoy Cc: Laurence Oberman Signed-off-by: Doug Ledford --- drivers/infiniband/ulp/srp/ib_srp.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c index e8225cc8b938..c7d97097d55c 100644 --- a/drivers/infiniband/ulp/srp/ib_srp.c +++ b/drivers/infiniband/ulp/srp/ib_srp.c @@ -466,9 +466,13 @@ static struct srp_fr_pool *srp_alloc_fr_pool(struct srp_target_port *target) * completion handler can access the queue pair while it is * being destroyed. */ -static void srp_destroy_qp(struct ib_qp *qp) +static void srp_destroy_qp(struct srp_rdma_ch *ch, struct ib_qp *qp) { - ib_drain_rq(qp); + spin_lock_irq(&ch->lock); + ib_process_cq_direct(ch->send_cq, -1); + spin_unlock_irq(&ch->lock); + + ib_drain_qp(qp); ib_destroy_qp(qp); } @@ -542,7 +546,7 @@ static int srp_create_ch_ib(struct srp_rdma_ch *ch) } if (ch->qp) - srp_destroy_qp(ch->qp); + srp_destroy_qp(ch, ch->qp); if (ch->recv_cq) ib_free_cq(ch->recv_cq); if (ch->send_cq) @@ -566,7 +570,7 @@ static int srp_create_ch_ib(struct srp_rdma_ch *ch) return 0; err_qp: - srp_destroy_qp(qp); + srp_destroy_qp(ch, qp); err_send_cq: ib_free_cq(send_cq); @@ -609,7 +613,7 @@ static void srp_free_ch_ib(struct srp_target_port *target, ib_destroy_fmr_pool(ch->fmr_pool); } - srp_destroy_qp(ch->qp); + srp_destroy_qp(ch, ch->qp); ib_free_cq(ch->send_cq); ib_free_cq(ch->recv_cq); @@ -1822,6 +1826,11 @@ static struct srp_iu *__srp_get_tx_iu(struct srp_rdma_ch *ch, return iu; } +/* + * Note: if this function is called from inside ib_drain_sq() then it will + * be called without ch->lock being held. If ib_drain_sq() dequeues a WQE + * with status IB_WC_SUCCESS then that's a bug. + */ static void srp_send_done(struct ib_cq *cq, struct ib_wc *wc) { struct srp_iu *iu = container_of(wc->wr_cqe, struct srp_iu, cqe); -- GitLab