IB/cq: Don't force IB_POLL_DIRECT poll context for ib_process_cq_direct

polling the completion queue directly does not interfere
with the existing polling logic, hence drop the requirement.
Be aware that running ib_process_cq_direct with non IB_POLL_DIRECT
CQ may trigger concurrent CQ processing.

This can be used for polling mode ULPs.

Cc: Bart Van Assche <bart.vanassche@wdc.com>
Reported-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
[maxg: added wcs array argument to __ib_process_cq]
Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

diff --git a/drivers/infiniband/core/cq.c b/drivers/infiniband/core/cq.c
index f2ae75f..c8c5a5a 100644 (file)
--- a/drivers/infiniband/core/cq.c
+++ b/drivers/infiniband/core/cq.c
@@ -25,9 +25,10 @@
 #define IB_POLL_FLAGS \
        (IB_CQ_NEXT_COMP | IB_CQ_REPORT_MISSED_EVENTS)
 
-static int __ib_process_cq(struct ib_cq *cq, int budget)
+static int __ib_process_cq(struct ib_cq *cq, int budget, struct ib_wc *poll_wc)
 {
        int i, n, completed = 0;
+       struct ib_wc *wcs = poll_wc ? : cq->wc;
 
        /*
         * budget might be (-1) if the caller does not
@@ -35,9 +36,9 @@ static int __ib_process_cq(struct ib_cq *cq, int budget)
         * minimum here.
         */
        while ((n = ib_poll_cq(cq, min_t(u32, IB_POLL_BATCH,
-                       budget - completed), cq->wc)) > 0) {
+                       budget - completed), wcs)) > 0) {
                for (i = 0; i < n; i++) {
-                       struct ib_wc *wc = &cq->wc[i];
+                       struct ib_wc *wc = &wcs[i];
 
                        if (wc->wr_cqe)
                                wc->wr_cqe->done(cq, wc);
@@ -60,18 +61,20 @@ static int __ib_process_cq(struct ib_cq *cq, int budget)
  * @cq:                CQ to process
  * @budget:    number of CQEs to poll for
  *
- * This function is used to process all outstanding CQ entries on a
- * %IB_POLL_DIRECT CQ.  It does not offload CQ processing to a different
- * context and does not ask for completion interrupts from the HCA.
+ * This function is used to process all outstanding CQ entries.
+ * It does not offload CQ processing to a different context and does
+ * not ask for completion interrupts from the HCA.
+ * Using direct processing on CQ with non IB_POLL_DIRECT type may trigger
+ * concurrent processing.
  *
  * Note: do not pass -1 as %budget unless it is guaranteed that the number
  * of completions that will be processed is small.
  */
 int ib_process_cq_direct(struct ib_cq *cq, int budget)
 {
-       WARN_ON_ONCE(cq->poll_ctx != IB_POLL_DIRECT);
+       struct ib_wc wcs[IB_POLL_BATCH];
 
-       return __ib_process_cq(cq, budget);
+       return __ib_process_cq(cq, budget, wcs);
 }
 EXPORT_SYMBOL(ib_process_cq_direct);
 
@@ -85,7 +88,7 @@ static int ib_poll_handler(struct irq_poll *iop, int budget)
        struct ib_cq *cq = container_of(iop, struct ib_cq, iop);
        int completed;
 
-       completed = __ib_process_cq(cq, budget);
+       completed = __ib_process_cq(cq, budget, NULL);
        if (completed < budget) {
                irq_poll_complete(&cq->iop);
                if (ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
@@ -105,7 +108,7 @@ static void ib_cq_poll_work(struct work_struct *work)
        struct ib_cq *cq = container_of(work, struct ib_cq, work);
        int completed;
 
-       completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE);
+       completed = __ib_process_cq(cq, IB_POLL_BUDGET_WORKQUEUE, NULL);
        if (completed >= IB_POLL_BUDGET_WORKQUEUE ||
            ib_req_notify_cq(cq, IB_POLL_FLAGS) > 0)
                queue_work(ib_comp_wq, &cq->work);