RDMA/ocrdma: EQ full catastrophe avoidance
Stale entries in the CQ being destroyed causes hardware to generate
EQEs indefinitely for a given CQ. Thus causing uncontrolled execution
of irq_handler. This patch fixes this using following sementics:
* irq_handler will ring EQ doorbell atleast once and implement budgeting scheme.
* cq_destroy will count number of valid entires during destroy and ring
cq-db so that hardware does not generate uncontrolled EQE.
* cq_destroy will synchronize with last running irq_handler instance.
* arm_cq will always defer arming CQ till poll_cq, except for the first arm_cq call.
* poll_cq will always ring cq-db with arm=SET if arm_cq was called prior to enter poll_cq.
* poll_cq will always ring cq-db with arm=UNSET if arm_cq was not called prior to enter poll_cq.
Signed-off-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Selvin Xavier <selvin.xavier@emulex.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
index f1108eb..7d59ed3 100644
--- a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
+++ b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c
@@ -910,6 +910,7 @@
spin_lock_init(&cq->comp_handler_lock);
INIT_LIST_HEAD(&cq->sq_head);
INIT_LIST_HEAD(&cq->rq_head);
+ cq->first_arm = true;
if (ib_ctx) {
uctx = get_ocrdma_ucontext(ib_ctx);
@@ -927,9 +928,7 @@
goto ctx_err;
}
cq->phase = OCRDMA_CQE_VALID;
- cq->arm_needed = true;
dev->cq_tbl[cq->id] = cq;
-
return &cq->ibcq;
ctx_err:
@@ -952,15 +951,52 @@
return status;
}
+static void ocrdma_flush_cq(struct ocrdma_cq *cq)
+{
+ int cqe_cnt;
+ int valid_count = 0;
+ unsigned long flags;
+
+ struct ocrdma_dev *dev = get_ocrdma_dev(cq->ibcq.device);
+ struct ocrdma_cqe *cqe = NULL;
+
+ cqe = cq->va;
+ cqe_cnt = cq->cqe_cnt;
+
+ /* Last irq might have scheduled a polling thread
+ * sync-up with it before hard flushing.
+ */
+ spin_lock_irqsave(&cq->cq_lock, flags);
+ while (cqe_cnt) {
+ if (is_cqe_valid(cq, cqe))
+ valid_count++;
+ cqe++;
+ cqe_cnt--;
+ }
+ ocrdma_ring_cq_db(dev, cq->id, false, false, valid_count);
+ spin_unlock_irqrestore(&cq->cq_lock, flags);
+}
+
int ocrdma_destroy_cq(struct ib_cq *ibcq)
{
int status;
struct ocrdma_cq *cq = get_ocrdma_cq(ibcq);
+ struct ocrdma_eq *eq = NULL;
struct ocrdma_dev *dev = get_ocrdma_dev(ibcq->device);
int pdid = 0;
+ u32 irq, indx;
+
+ dev->cq_tbl[cq->id] = NULL;
+ indx = ocrdma_get_eq_table_index(dev, cq->eqn);
+ if (indx == -EINVAL)
+ BUG();
+
+ eq = &dev->eq_tbl[indx];
+ irq = ocrdma_get_irq(dev, eq);
+ synchronize_irq(irq);
+ ocrdma_flush_cq(cq);
status = ocrdma_mbx_destroy_cq(dev, cq);
-
if (cq->ucontext) {
pdid = cq->ucontext->cntxt_pd->id;
ocrdma_del_mmap(cq->ucontext, (u64) cq->pa,
@@ -969,7 +1005,6 @@
ocrdma_get_db_addr(dev, pdid),
dev->nic_info.db_page_size);
}
- dev->cq_tbl[cq->id] = NULL;
kfree(cq);
return status;
@@ -2705,10 +2740,18 @@
}
stop_cqe:
cq->getp = cur_getp;
- if (polled_hw_cqes || expand || stop) {
- ocrdma_ring_cq_db(dev, cq->id, cq->armed, cq->solicited,
+ if (cq->deferred_arm) {
+ ocrdma_ring_cq_db(dev, cq->id, true, cq->deferred_sol,
polled_hw_cqes);
+ cq->deferred_arm = false;
+ cq->deferred_sol = false;
+ } else {
+ /* We need to pop the CQE. No need to arm */
+ ocrdma_ring_cq_db(dev, cq->id, false, cq->deferred_sol,
+ polled_hw_cqes);
+ cq->deferred_sol = false;
}
+
return i;
}
@@ -2780,30 +2823,28 @@
struct ocrdma_cq *cq = get_ocrdma_cq(ibcq);
struct ocrdma_dev *dev = get_ocrdma_dev(ibcq->device);
u16 cq_id;
- u16 cur_getp;
- struct ocrdma_cqe *cqe;
unsigned long flags;
+ bool arm_needed = false, sol_needed = false;
cq_id = cq->id;
spin_lock_irqsave(&cq->cq_lock, flags);
if (cq_flags & IB_CQ_NEXT_COMP || cq_flags & IB_CQ_SOLICITED)
- cq->armed = true;
+ arm_needed = true;
if (cq_flags & IB_CQ_SOLICITED)
- cq->solicited = true;
+ sol_needed = true;
- cur_getp = cq->getp;
- cqe = cq->va + cur_getp;
-
- /* check whether any valid cqe exist or not, if not then safe to
- * arm. If cqe is not yet consumed, then let it get consumed and then
- * we arm it to avoid false interrupts.
- */
- if (!is_cqe_valid(cq, cqe) || cq->arm_needed) {
- cq->arm_needed = false;
- ocrdma_ring_cq_db(dev, cq_id, cq->armed, cq->solicited, 0);
+ if (cq->first_arm) {
+ ocrdma_ring_cq_db(dev, cq_id, arm_needed, sol_needed, 0);
+ cq->first_arm = false;
+ goto skip_defer;
}
+ cq->deferred_arm = true;
+
+skip_defer:
+ cq->deferred_sol = sol_needed;
spin_unlock_irqrestore(&cq->cq_lock, flags);
+
return 0;
}