IB/ehca: Refactor sync between completions and destroy_cq using atomic_t

[cascardo/linux.git] / drivers / infiniband / hw / ehca / ehca_cq.c

diff --git a/drivers/infiniband/hw/ehca/ehca_cq.c b/drivers/infiniband/hw/ehca/ehca_cq.c
index 67f0670..3729997 100644 (file)
--- a/drivers/infiniband/hw/ehca/ehca_cq.c
+++ b/drivers/infiniband/hw/ehca/ehca_cq.c
@@ -56,11 +56,11 @@ int ehca_cq_assign_qp(struct ehca_cq *cq, struct ehca_qp *qp)
 {
        unsigned int qp_num = qp->real_qp_num;
        unsigned int key = qp_num & (QP_HASHTAB_LEN-1);
-       unsigned long spl_flags;
+       unsigned long flags;
 
-       spin_lock_irqsave(&cq->spinlock, spl_flags);
+       spin_lock_irqsave(&cq->spinlock, flags);
        hlist_add_head(&qp->list_entries, &cq->qp_hashtab[key]);
-       spin_unlock_irqrestore(&cq->spinlock, spl_flags);
+       spin_unlock_irqrestore(&cq->spinlock, flags);
 
        ehca_dbg(cq->ib_cq.device, "cq_num=%x real_qp_num=%x",
                 cq->cq_number, qp_num);
@@ -74,9 +74,9 @@ int ehca_cq_unassign_qp(struct ehca_cq *cq, unsigned int real_qp_num)
        unsigned int key = real_qp_num & (QP_HASHTAB_LEN-1);
        struct hlist_node *iter;
        struct ehca_qp *qp;
-       unsigned long spl_flags;
+       unsigned long flags;
 
-       spin_lock_irqsave(&cq->spinlock, spl_flags);
+       spin_lock_irqsave(&cq->spinlock, flags);
        hlist_for_each(iter, &cq->qp_hashtab[key]) {
                qp = hlist_entry(iter, struct ehca_qp, list_entries);
                if (qp->real_qp_num == real_qp_num) {
@@ -88,7 +88,7 @@ int ehca_cq_unassign_qp(struct ehca_cq *cq, unsigned int real_qp_num)
                        break;
                }
        }
-       spin_unlock_irqrestore(&cq->spinlock, spl_flags);
+       spin_unlock_irqrestore(&cq->spinlock, flags);
        if (ret)
                ehca_err(cq->ib_cq.device,
                         "qp not found cq_num=%x real_qp_num=%x",
@@ -146,6 +146,7 @@ struct ib_cq *ehca_create_cq(struct ib_device *device, int cqe, int comp_vector,
        spin_lock_init(&my_cq->spinlock);
        spin_lock_init(&my_cq->cb_lock);
        spin_lock_init(&my_cq->task_lock);
+       atomic_set(&my_cq->nr_events, 0);
        init_waitqueue_head(&my_cq->wait_completion);
        my_cq->ownpid = current->tgid;
 
@@ -303,16 +304,6 @@ create_cq_exit1:
        return cq;
 }
 
-static int get_cq_nr_events(struct ehca_cq *my_cq)
-{
-       int ret;
-       unsigned long flags;
-       spin_lock_irqsave(&ehca_cq_idr_lock, flags);
-       ret = my_cq->nr_events;
-       spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
-       return ret;
-}
-
 int ehca_destroy_cq(struct ib_cq *cq)
 {
        u64 h_ret;
@@ -339,17 +330,18 @@ int ehca_destroy_cq(struct ib_cq *cq)
                }
        }
 
+       /*
+        * remove the CQ from the idr first to make sure
+        * no more interrupt tasklets will touch this CQ
+        */
        spin_lock_irqsave(&ehca_cq_idr_lock, flags);
-       while (my_cq->nr_events) {
-               spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
-               wait_event(my_cq->wait_completion, !get_cq_nr_events(my_cq));
-               spin_lock_irqsave(&ehca_cq_idr_lock, flags);
-               /* recheck nr_events to assure no cqe has just arrived */
-       }
-
        idr_remove(&ehca_cq_idr, my_cq->token);
        spin_unlock_irqrestore(&ehca_cq_idr_lock, flags);
 
+       /* now wait until all pending events have completed */
+       wait_event(my_cq->wait_completion, !atomic_read(&my_cq->nr_events));
+
+       /* nobody's using our CQ any longer -- we can destroy it */
        h_ret = hipz_h_destroy_cq(adapter_handle, my_cq, 0);
        if (h_ret == H_R_STATE) {
                /* cq in err: read err data and destroy it forcibly */