IB/iser: Optimize completion polling

Poll in batch of 16. Since we don't want it on the stack, keep under
iser completion context (iser_comp).

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

2 files changed, 11 insertions, 5 deletions

diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.h b/drivers/infiniband/ulp/iser/iscsi_iser.h
index 4fcb25604d80..6c3743b6860e 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.h
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.h
@@ -145,6 +145,8 @@
                                         ISER_MAX_TX_MISC_PDUS         + \
                                         ISER_MAX_RX_MISC_PDUS)
 
+#define ISER_WC_BATCH_COUNT   16
+
 #define ISER_VER                        0x10
 #define ISER_WSV                        0x08
 #define ISER_RSV                        0x04
@@ -273,6 +275,7 @@ struct iscsi_iser_task;
  *
  * @device:     pointer to device handle
  * @cq:         completion queue
+ * @wcs:        work completion array
  * @tasklet:    Tasklet handle
  * @active_qps: Number of active QPs attached
  *              to completion context
@@ -280,6 +283,7 @@ struct iscsi_iser_task;
 struct iser_comp {
         struct iser_device      *device;
         struct ib_cq            *cq;
+        struct ib_wc             wcs[ISER_WC_BATCH_COUNT];
         struct tasklet_struct    tasklet;
         int                      active_qps;
 };
diff --git a/drivers/infiniband/ulp/iser/iser_verbs.c b/drivers/infiniband/ulp/iser/iser_verbs.c
index 805a9bdc9520..82bedbc260b2 100644
--- a/drivers/infiniband/ulp/iser/iser_verbs.c
+++ b/drivers/infiniband/ulp/iser/iser_verbs.c
@@ -1232,13 +1232,15 @@ static void iser_cq_tasklet_fn(unsigned long data)
 {
         struct iser_comp *comp = (struct iser_comp *)data;
         struct ib_cq *cq = comp->cq;
-        struct ib_wc wc;
-        int completed = 0;
+        struct ib_wc *const wcs = comp->wcs;
+        int i, n, completed = 0;
 
-        while (ib_poll_cq(cq, 1, &wc) == 1) {
-                iser_handle_wc(&wc);
+        while ((n = ib_poll_cq(cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
+                for (i = 0; i < n; i++)
+                        iser_handle_wc(&wcs[i]);
 
-                if (++completed >= iser_cq_poll_limit)
+                completed += n;
+                if (completed >= iser_cq_poll_limit)
                         break;
         }