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Subject[137/262] can bcm: fix tx_setup off-by-one errors
3.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Oliver Hartkopp <socketcan@hartkopp.net>

[ Upstream commit aabdcb0b553b9c9547b1a506b34d55a764745870 ]

This patch fixes two off-by-one errors that canceled each other out.
Checking for the same condition two times in bcm_tx_timeout_tsklet() reduced
the count of frames to be sent by one. This did not show up the first time
tx_setup is invoked as an additional frame is sent due to TX_ANNONCE.
Invoking a second tx_setup on the same item led to a reduced (by 1) number of
sent frames.

Reported-by: Andre Naujoks <nautsch@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/can/bcm.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -364,9 +364,6 @@ static void bcm_tx_timeout_tsklet(unsign

bcm_send_to_user(op, &msg_head, NULL, 0);
}
- }
-
- if (op->kt_ival1.tv64 && (op->count > 0)) {

/* send (next) frame */
bcm_can_tx(op);
@@ -969,8 +966,9 @@ static int bcm_tx_setup(struct bcm_msg_h
/* spec: send can_frame when starting timer */
op->flags |= TX_ANNOUNCE;

- if (op->kt_ival1.tv64 && (op->count > 0)) {
- /* op->count-- is done in bcm_tx_timeout_handler */
+ /* 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
@@ -978,8 +976,11 @@ static int bcm_tx_setup(struct bcm_msg_h
HRTIMER_MODE_REL);
}

- if (op->flags & TX_ANNOUNCE)
+ if (op->flags & TX_ANNOUNCE) {
bcm_can_tx(op);
+ if (op->kt_ival1.tv64 && (op->count > 0))
+ op->count--;
+ }

return msg_head->nframes * CFSIZ + MHSIZ;
}



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