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Date: Mon, 16 May 2011 22:04:51 +0100
From: Ben Hutchings <bhutchings@...arflare.com>
To: David Miller <davem@...emloft.net>
Cc: netdev@...r.kernel.org
Subject: [PATCH net-2.6] net: Keep TX queues stopped as long as the
physical device is absent
netif_device_detach() stops all TX queues, but there is nothing to
prevent them from being restarted. In fact, netif_tx_unlock() may now
do this. Add another queue state flag that is set while the device is
absent, and make netif_tx_queue_frozen_or_stopped() test it. Rename the
function to netif_tx_queue_blocked() since it makes little sense to keep
adding flags to its name.
This bug appears to have been present forever, but had little effect
before commit c3f26a269c2421f97f10cf8ed05d5099b573af4d ('netdev: Fix
lockdep warnings in multiqueue configurations.').
Signed-off-by: Ben Hutchings <bhutchings@...arflare.com>
Cc: stable@...nel.org
---
include/linux/netdevice.h | 19 +++++++++++++++----
net/core/dev.c | 16 ++++++++++++++++
net/core/netpoll.c | 2 +-
net/core/pktgen.c | 2 +-
net/sched/sch_generic.c | 6 +++---
net/sched/sch_teql.c | 2 +-
6 files changed, 37 insertions(+), 10 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0249fe7..1727723 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -544,8 +544,10 @@ static inline void napi_synchronize(const struct napi_struct *n)
enum netdev_queue_state_t {
__QUEUE_STATE_XOFF,
__QUEUE_STATE_FROZEN,
-#define QUEUE_STATE_XOFF_OR_FROZEN ((1 << __QUEUE_STATE_XOFF) | \
- (1 << __QUEUE_STATE_FROZEN))
+ __QUEUE_STATE_ABSENT,
+#define QUEUE_STATE_BLOCKED ((1 << __QUEUE_STATE_XOFF) | \
+ (1 << __QUEUE_STATE_FROZEN) | \
+ (1 << __QUEUE_STATE_ABSENT))
};
struct netdev_queue {
@@ -1897,9 +1899,18 @@ static inline int netif_queue_stopped(const struct net_device *dev)
return netif_tx_queue_stopped(netdev_get_tx_queue(dev, 0));
}
-static inline int netif_tx_queue_frozen_or_stopped(const struct netdev_queue *dev_queue)
+/**
+ * netif_tx_queue_blocked - test if TX queue is blocked for any reason
+ * @dev_queue: Transmit queue
+ *
+ * Test whether transmit queue is blocked. This could happen
+ * because it was explicitly stopped (usually due to a hardware
+ * queue filling up), because the device transmit state is locked,
+ * or because the hardware device was detached.
+ */
+static inline int netif_tx_queue_blocked(const struct netdev_queue *dev_queue)
{
- return dev_queue->state & QUEUE_STATE_XOFF_OR_FROZEN;
+ return dev_queue->state & QUEUE_STATE_BLOCKED;
}
/**
diff --git a/net/core/dev.c b/net/core/dev.c
index 9200944..6b1205a 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1740,6 +1740,14 @@ EXPORT_SYMBOL(dev_kfree_skb_any);
*/
void netif_device_detach(struct net_device *dev)
{
+ struct netdev_queue *txq;
+ unsigned int i;
+
+ for (i = 0; i < dev->num_tx_queues; i++) {
+ txq = netdev_get_tx_queue(dev, i);
+ set_bit(__QUEUE_STATE_ABSENT, &txq->state);
+ }
+
if (test_and_clear_bit(__LINK_STATE_PRESENT, &dev->state) &&
netif_running(dev)) {
netif_tx_stop_all_queues(dev);
@@ -1755,6 +1763,14 @@ EXPORT_SYMBOL(netif_device_detach);
*/
void netif_device_attach(struct net_device *dev)
{
+ struct netdev_queue *txq;
+ unsigned int i;
+
+ for (i = 0; i < dev->num_tx_queues; i++) {
+ txq = netdev_get_tx_queue(dev, i);
+ clear_bit(__QUEUE_STATE_ABSENT, &txq->state);
+ }
+
if (!test_and_set_bit(__LINK_STATE_PRESENT, &dev->state) &&
netif_running(dev)) {
netif_tx_wake_all_queues(dev);
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 06be243..dac4c2c 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -75,7 +75,7 @@ static void queue_process(struct work_struct *work)
local_irq_save(flags);
__netif_tx_lock(txq, smp_processor_id());
- if (netif_tx_queue_frozen_or_stopped(txq) ||
+ if (netif_tx_queue_blocked(txq) ||
ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
skb_queue_head(&npinfo->txq, skb);
__netif_tx_unlock(txq);
diff --git a/net/core/pktgen.c b/net/core/pktgen.c
index aeeece7..8dcf293 100644
--- a/net/core/pktgen.c
+++ b/net/core/pktgen.c
@@ -3478,7 +3478,7 @@ static void pktgen_xmit(struct pktgen_dev *pkt_dev)
__netif_tx_lock_bh(txq);
- if (unlikely(netif_tx_queue_frozen_or_stopped(txq))) {
+ if (unlikely(netif_tx_queue_blocked(txq))) {
ret = NETDEV_TX_BUSY;
pkt_dev->last_ok = 0;
goto unlock;
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index c84b659..df6d01b 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -60,7 +60,7 @@ static inline struct sk_buff *dequeue_skb(struct Qdisc *q)
/* check the reason of requeuing without tx lock first */
txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
- if (!netif_tx_queue_frozen_or_stopped(txq)) {
+ if (!netif_tx_queue_blocked(txq)) {
q->gso_skb = NULL;
q->q.qlen--;
} else
@@ -121,7 +121,7 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
spin_unlock(root_lock);
HARD_TX_LOCK(dev, txq, smp_processor_id());
- if (!netif_tx_queue_frozen_or_stopped(txq))
+ if (!netif_tx_queue_blocked(txq))
ret = dev_hard_start_xmit(skb, dev, txq);
HARD_TX_UNLOCK(dev, txq);
@@ -143,7 +143,7 @@ int sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
ret = dev_requeue_skb(skb, q);
}
- if (ret && netif_tx_queue_frozen_or_stopped(txq))
+ if (ret && netif_tx_queue_blocked(txq))
ret = 0;
return ret;
diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c
index 45cd300..f876462 100644
--- a/net/sched/sch_teql.c
+++ b/net/sched/sch_teql.c
@@ -312,7 +312,7 @@ restart:
if (__netif_tx_trylock(slave_txq)) {
unsigned int length = qdisc_pkt_len(skb);
- if (!netif_tx_queue_frozen_or_stopped(slave_txq) &&
+ if (!netif_tx_queue_blocked(slave_txq) &&
slave_ops->ndo_start_xmit(skb, slave) == NETDEV_TX_OK) {
txq_trans_update(slave_txq);
__netif_tx_unlock(slave_txq);
--
1.7.4
--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
--
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