From: Kumar Sanghvi Date: Mon, 24 Oct 2011 15:50:22 +0000 (+0530) Subject: RDMA/cxgb3: Serialize calls to CQ's comp_handler X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f7cc25d018f1e9af6767ee7774bbe83452e9fdf4;p=linux-beck.git RDMA/cxgb3: Serialize calls to CQ's comp_handler iw_cxgb3 has a potential problem where a CQ's comp_handler can get called simultaneously from different places in iw_cxgb3 driver. This does not comply with Documentation/infiniband/core_locking.txt, which states that at a given point of time, there should be only one callback per CQ should be active. Such problem was reported by Parav Pandit for iw_cxgb4 driver. Based on discussion between Parav Pandit and Steve Wise, this patch fixes the above problem by serializing the calls to a CQ's comp_handler using a spin_lock. Signed-off-by: Kumar Sanghvi Acked-by: Steve Wise Signed-off-by: Roland Dreier --- diff --git a/drivers/infiniband/hw/cxgb3/iwch_ev.c b/drivers/infiniband/hw/cxgb3/iwch_ev.c index 71e0d845da3d..abcc9e76962b 100644 --- a/drivers/infiniband/hw/cxgb3/iwch_ev.c +++ b/drivers/infiniband/hw/cxgb3/iwch_ev.c @@ -46,6 +46,7 @@ static void post_qp_event(struct iwch_dev *rnicp, struct iwch_cq *chp, struct ib_event event; struct iwch_qp_attributes attrs; struct iwch_qp *qhp; + unsigned long flag; spin_lock(&rnicp->lock); qhp = get_qhp(rnicp, CQE_QPID(rsp_msg->cqe)); @@ -94,7 +95,9 @@ static void post_qp_event(struct iwch_dev *rnicp, struct iwch_cq *chp, if (qhp->ibqp.event_handler) (*qhp->ibqp.event_handler)(&event, qhp->ibqp.qp_context); + spin_lock_irqsave(&chp->comp_handler_lock, flag); (*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context); + spin_unlock_irqrestore(&chp->comp_handler_lock, flag); if (atomic_dec_and_test(&qhp->refcnt)) wake_up(&qhp->wait); @@ -107,6 +110,7 @@ void iwch_ev_dispatch(struct cxio_rdev *rdev_p, struct sk_buff *skb) struct iwch_cq *chp; struct iwch_qp *qhp; u32 cqid = RSPQ_CQID(rsp_msg); + unsigned long flag; rnicp = (struct iwch_dev *) rdev_p->ulp; spin_lock(&rnicp->lock); @@ -170,7 +174,9 @@ void iwch_ev_dispatch(struct cxio_rdev *rdev_p, struct sk_buff *skb) */ if (qhp->ep && SQ_TYPE(rsp_msg->cqe)) dst_confirm(qhp->ep->dst); + spin_lock_irqsave(&chp->comp_handler_lock, flag); (*chp->ibcq.comp_handler)(&chp->ibcq, chp->ibcq.cq_context); + spin_unlock_irqrestore(&chp->comp_handler_lock, flag); break; case TPT_ERR_STAG: diff --git a/drivers/infiniband/hw/cxgb3/iwch_provider.c b/drivers/infiniband/hw/cxgb3/iwch_provider.c index c7d9411f2954..37c224fc3ad9 100644 --- a/drivers/infiniband/hw/cxgb3/iwch_provider.c +++ b/drivers/infiniband/hw/cxgb3/iwch_provider.c @@ -190,6 +190,7 @@ static struct ib_cq *iwch_create_cq(struct ib_device *ibdev, int entries, int ve chp->rhp = rhp; chp->ibcq.cqe = 1 << chp->cq.size_log2; spin_lock_init(&chp->lock); + spin_lock_init(&chp->comp_handler_lock); atomic_set(&chp->refcnt, 1); init_waitqueue_head(&chp->wait); if (insert_handle(rhp, &rhp->cqidr, chp, chp->cq.cqid)) { diff --git a/drivers/infiniband/hw/cxgb3/iwch_provider.h b/drivers/infiniband/hw/cxgb3/iwch_provider.h index 9a342c9b220d..87c14b0c5ac0 100644 --- a/drivers/infiniband/hw/cxgb3/iwch_provider.h +++ b/drivers/infiniband/hw/cxgb3/iwch_provider.h @@ -103,6 +103,7 @@ struct iwch_cq { struct iwch_dev *rhp; struct t3_cq cq; spinlock_t lock; + spinlock_t comp_handler_lock; atomic_t refcnt; wait_queue_head_t wait; u32 __user *user_rptr_addr; diff --git a/drivers/infiniband/hw/cxgb3/iwch_qp.c b/drivers/infiniband/hw/cxgb3/iwch_qp.c index ecd313f359a4..bea5839d89ee 100644 --- a/drivers/infiniband/hw/cxgb3/iwch_qp.c +++ b/drivers/infiniband/hw/cxgb3/iwch_qp.c @@ -822,8 +822,11 @@ static void __flush_qp(struct iwch_qp *qhp, struct iwch_cq *rchp, flushed = cxio_flush_rq(&qhp->wq, &rchp->cq, count); spin_unlock(&qhp->lock); spin_unlock_irqrestore(&rchp->lock, *flag); - if (flushed) + if (flushed) { + spin_lock_irqsave(&rchp->comp_handler_lock, *flag); (*rchp->ibcq.comp_handler)(&rchp->ibcq, rchp->ibcq.cq_context); + spin_unlock_irqrestore(&rchp->comp_handler_lock, *flag); + } /* locking hierarchy: cq lock first, then qp lock. */ spin_lock_irqsave(&schp->lock, *flag); @@ -833,8 +836,11 @@ static void __flush_qp(struct iwch_qp *qhp, struct iwch_cq *rchp, flushed = cxio_flush_sq(&qhp->wq, &schp->cq, count); spin_unlock(&qhp->lock); spin_unlock_irqrestore(&schp->lock, *flag); - if (flushed) + if (flushed) { + spin_lock_irqsave(&schp->comp_handler_lock, *flag); (*schp->ibcq.comp_handler)(&schp->ibcq, schp->ibcq.cq_context); + spin_unlock_irqrestore(&schp->comp_handler_lock, *flag); + } /* deref */ if (atomic_dec_and_test(&qhp->refcnt)) @@ -853,11 +859,15 @@ static void flush_qp(struct iwch_qp *qhp, unsigned long *flag) if (qhp->ibqp.uobject) { cxio_set_wq_in_error(&qhp->wq); cxio_set_cq_in_error(&rchp->cq); + spin_lock_irqsave(&rchp->comp_handler_lock, *flag); (*rchp->ibcq.comp_handler)(&rchp->ibcq, rchp->ibcq.cq_context); + spin_unlock_irqrestore(&rchp->comp_handler_lock, *flag); if (schp != rchp) { cxio_set_cq_in_error(&schp->cq); + spin_lock_irqsave(&schp->comp_handler_lock, *flag); (*schp->ibcq.comp_handler)(&schp->ibcq, schp->ibcq.cq_context); + spin_unlock_irqrestore(&schp->comp_handler_lock, *flag); } return; }