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net: qdisc: use rcu prefix and silence sparse warnings

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Add __rcu notation to qdisc handling by doing this we can make
smatch output more legible. And anyways some of the cases should
be using rcu_dereference() see qdisc_all_tx_empty(),
qdisc_tx_chainging(), and so on.

Also *wake_queue() API is commonly called from driver timer routines
without rcu lock or rtnl lock. So I added rcu_read_lock() blocks
around netif_wake_subqueue and netif_tx_wake_queue.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Fastabend
2014-09-12 20:04:52 -07:00
committed by David S. Miller
parent d1015645dd
commit 46e5da40ae
6 changed files with 82 additions and 42 deletions
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21
include/net/sch_generic.h
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@@ -259,7 +259,9 @@ static inline spinlock_t *qdisc_lock(struct Qdisc *qdisc)
static inline struct Qdisc *qdisc_root(const struct Qdisc *qdisc)
{
return qdisc->dev_queue->qdisc;
struct Qdisc *q = rcu_dereference_rtnl(qdisc->dev_queue->qdisc);
return q;
}
static inline struct Qdisc *qdisc_root_sleeping(const struct Qdisc *qdisc)
@@ -384,7 +386,7 @@ static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
struct Qdisc *qdisc;
for (; i < dev->num_tx_queues; i++) {
qdisc = netdev_get_tx_queue(dev, i)->qdisc;
qdisc = rtnl_dereference(netdev_get_tx_queue(dev, i)->qdisc);
if (qdisc) {
spin_lock_bh(qdisc_lock(qdisc));
qdisc_reset(qdisc);
@@ -402,13 +404,18 @@ static inline void qdisc_reset_all_tx(struct net_device *dev)
static inline bool qdisc_all_tx_empty(const struct net_device *dev)
{
unsigned int i;
rcu_read_lock();
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
const struct Qdisc *q = txq->qdisc;
const struct Qdisc *q = rcu_dereference(txq->qdisc);
if (q->q.qlen)
if (q->q.qlen) {
rcu_read_unlock();
return false;
}
}
rcu_read_unlock();
return true;
}
@@ -416,9 +423,10 @@ static inline bool qdisc_all_tx_empty(const struct net_device *dev)
static inline bool qdisc_tx_changing(const struct net_device *dev)
{
unsigned int i;
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (txq->qdisc != txq->qdisc_sleeping)
if (rcu_access_pointer(txq->qdisc) != txq->qdisc_sleeping)
return true;
}
return false;
@@ -428,9 +436,10 @@ static inline bool qdisc_tx_changing(const struct net_device *dev)
static inline bool qdisc_tx_is_noop(const struct net_device *dev)
{
unsigned int i;
for (i = 0; i < dev->num_tx_queues; i++) {
struct netdev_queue *txq = netdev_get_tx_queue(dev, i);
if (txq->qdisc != &noop_qdisc)
if (rcu_access_pointer(txq->qdisc) != &noop_qdisc)
return false;
}
return true;