[ 107/147] rapidio/rionet: fix multicast packet transmit logic

Ben Hutchings
2012-10-14T14:43:03Z

From: Alexandre Bounine <alexandre.bounine@idt.com>

commit 7c4a6106d6451fc03c491e61df37c044505d843a upstream.

Fix multicast packet transmit logic to account for repetitive transmission
of single skb:
- correct check for available buffers (this bug may produce NULL pointer
crash dump in case of heavy traffic);
- update skb user count (incorrect user counter causes a warning dump from
net_tx_action routine during multicast transfers in systems with three or
more rionet participants).

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/net/rionet.c | 20 +++++++++++++++++---
1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/net/rionet.c b/drivers/net/rionet.c
index 91d2588..1470d3e 100644
--- a/drivers/net/rionet.c
+++ b/drivers/net/rionet.c
@@ -79,6 +79,7 @@ static int rionet_capable = 1;
* on system trade-offs.
*/
static struct rio_dev **rionet_active;
+static int nact; /* total number of active rionet peers */

#define is_rionet_capable(src_ops, dst_ops) \
((src_ops & RIO_SRC_OPS_DATA_MSG) && \
@@ -175,6 +176,7 @@ static int rionet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
struct ethhdr *eth = (struct ethhdr *)skb->data;
u16 destid;
unsigned long flags;
+ int add_num = 1;

local_irq_save(flags);
if (!spin_trylock(&rnet->tx_lock)) {
@@ -182,7 +184,10 @@ static int rionet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
return NETDEV_TX_LOCKED;
}

- if ((rnet->tx_cnt + 1) > RIONET_TX_RING_SIZE) {
+ if (is_multicast_ether_addr(eth->h_dest))
+ add_num = nact;
+
+ if ((rnet->tx_cnt + add_num) > RIONET_TX_RING_SIZE) {
netif_stop_queue(ndev);
spin_unlock_irqrestore(&rnet->tx_lock, flags);
printk(KERN_ERR "%s: BUG! Tx Ring full when queue awake!\n",
@@ -191,11 +196,16 @@ static int rionet_start_xmit(struct sk_buff *skb, struct net_device *ndev)
}

if (is_multicast_ether_addr(eth->h_dest)) {
+ int count = 0;
for (i = 0; i < RIO_MAX_ROUTE_ENTRIES(rnet->mport->sys_size);
i++)
- if (rionet_active[i])
+ if (rionet_active[i]) {
rionet_queue_tx_msg(skb, ndev,
rionet_active[i]);
+ if (count)
+ atomic_inc(&skb->users);
+ count++;
+ }
} else if (RIONET_MAC_MATCH(eth->h_dest)) {
destid = RIONET_GET_DESTID(eth->h_dest);
if (rionet_active[destid])
@@ -220,14 +230,17 @@ static void rionet_dbell_event(struct rio_mport *mport, void *dev_id, u16 sid, u
if (info == RIONET_DOORBELL_JOIN) {
if (!rionet_active[sid]) {
list_for_each_entry(peer, &rionet_peers, node) {
- if (peer->rdev->destid == sid)
+ if (peer->rdev->destid == sid) {
rionet_active[sid] = peer->rdev;
+ nact++;
+ }
}
rio_mport_send_doorbell(mport, sid,
RIONET_DOORBELL_JOIN);
}
} else if (info == RIONET_DOORBELL_LEAVE) {
rionet_active[sid] = NULL;
+ nact--;
} else {
if (netif_msg_intr(rnet))
printk(KERN_WARNING "%s: unhandled doorbell\n",
@@ -523,6 +536,7 @@ static int rionet_probe(struct rio_dev *rdev, const struct rio_device_id *id)

rc = rionet_setup_netdev(rdev->net->hport, ndev);
rionet_check = 1;
+ nact = 0;
}

/*