can bcm: fix incomplete tx_setup fix

The commit aabdcb0b553b9c9547b1a506b34d55a764745870 ("can bcm: fix tx_setup
off-by-one errors") fixed only a part of the original problem reported by
Andre Naujoks. It turned out that the original code needed to be re-ordered
to reduce complexity and to finally fix the reported frame counting issues.

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 21 insertions, 27 deletions

diff --git a/net/can/bcm.c b/net/can/bcm.c
index c9cdb8d78e70..c84963d2dee6 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -344,6 +344,18 @@ static void bcm_send_to_user(struct bcm_op *op, struct bcm_msg_head *head,
         }
 }
 
+static void bcm_tx_start_timer(struct bcm_op *op)
+{
+        if (op->kt_ival1.tv64 && op->count)
+                hrtimer_start(&op->timer,
+                              ktime_add(ktime_get(), op->kt_ival1),
+                              HRTIMER_MODE_ABS);
+        else if (op->kt_ival2.tv64)
+                hrtimer_start(&op->timer,
+                              ktime_add(ktime_get(), op->kt_ival2),
+                              HRTIMER_MODE_ABS);
+}
+
 static void bcm_tx_timeout_tsklet(unsigned long data)
 {
         struct bcm_op *op = (struct bcm_op *)data;
@@ -365,23 +377,12 @@ static void bcm_tx_timeout_tsklet(unsigned long data)
 
                         bcm_send_to_user(op, &msg_head, NULL, 0);
                 }
-
-                /* send (next) frame */
                 bcm_can_tx(op);
-                hrtimer_start(&op->timer,
-                              ktime_add(ktime_get(), op->kt_ival1),
-                              HRTIMER_MODE_ABS);
 
-        } else {
-                if (op->kt_ival2.tv64) {
+        } else if (op->kt_ival2.tv64)
+                bcm_can_tx(op);
 
-                        /* send (next) frame */
-                        bcm_can_tx(op);
-                        hrtimer_start(&op->timer,
-                                      ktime_add(ktime_get(), op->kt_ival2),
-                                      HRTIMER_MODE_ABS);
-                }
-        }
+        bcm_tx_start_timer(op);
 }
 
 /*
@@ -961,28 +962,21 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg,
                         hrtimer_cancel(&op->timer);
         }
 
-        if ((op->flags & STARTTIMER) &&
-            ((op->kt_ival1.tv64 && op->count) || op->kt_ival2.tv64)) {
-
+        if (op->flags & STARTTIMER) {
+                hrtimer_cancel(&op->timer);
                 /* spec: send can_frame when starting timer */
                 op->flags |= TX_ANNOUNCE;
-
-                /* only start timer when having more frames than sent below */
-                if (op->kt_ival1.tv64 && (op->count > 1)) {
-                        /* op->count-- is done in bcm_tx_timeout_tsklet */
-                        hrtimer_start(&op->timer, op->kt_ival1,
-                                      HRTIMER_MODE_REL);
-                } else
-                        hrtimer_start(&op->timer, op->kt_ival2,
-                                      HRTIMER_MODE_REL);
         }
 
         if (op->flags & TX_ANNOUNCE) {
                 bcm_can_tx(op);
-                if (op->kt_ival1.tv64 && (op->count > 0))
+                if (op->count)
                         op->count--;
         }
 
+        if (op->flags & STARTTIMER)
+                bcm_tx_start_timer(op);
+
         return msg_head->nframes * CFSIZ + MHSIZ;
 }