From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit bf955b5ab8f6f7b0632cdef8e36b14e4f6e77829 ]
While reading weight_p, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.
Also, dev_[rt]x_weight can be read/written at the same time. So, we need to use READ_ONCE() and WRITE_ONCE() for its access. Moreover, to use the same weight_p while changing dev_[rt]x_weight, we add a mutex in proc_do_dev_weight().
Fixes: 3d48b53fb2ae ("net: dev_weight: TX/RX orthogonality") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima kuniyu@amazon.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/dev.c | 2 +- net/core/sysctl_net_core.c | 15 +++++++++------ net/sched/sch_generic.c | 2 +- 3 files changed, 11 insertions(+), 8 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c index ea09e0809c122..51721fb2e30cf 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5186,7 +5186,7 @@ static int process_backlog(struct napi_struct *napi, int quota) net_rps_action_and_irq_enable(sd); }
- napi->weight = dev_rx_weight; + napi->weight = READ_ONCE(dev_rx_weight); while (again) { struct sk_buff *skb;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c index ac1a32d5cad3c..1b5749f2ef9c0 100644 --- a/net/core/sysctl_net_core.c +++ b/net/core/sysctl_net_core.c @@ -229,14 +229,17 @@ static int set_default_qdisc(struct ctl_table *table, int write, static int proc_do_dev_weight(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { - int ret; + static DEFINE_MUTEX(dev_weight_mutex); + int ret, weight;
+ mutex_lock(&dev_weight_mutex); ret = proc_dointvec(table, write, buffer, lenp, ppos); - if (ret != 0) - return ret; - - dev_rx_weight = weight_p * dev_weight_rx_bias; - dev_tx_weight = weight_p * dev_weight_tx_bias; + if (!ret && write) { + weight = READ_ONCE(weight_p); + WRITE_ONCE(dev_rx_weight, weight * dev_weight_rx_bias); + WRITE_ONCE(dev_tx_weight, weight * dev_weight_tx_bias); + } + mutex_unlock(&dev_weight_mutex);
return ret; } diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 82752dcbf2a2c..4a76ceeca6fdd 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -251,7 +251,7 @@ static inline int qdisc_restart(struct Qdisc *q, int *packets)
void __qdisc_run(struct Qdisc *q) { - int quota = dev_tx_weight; + int quota = READ_ONCE(dev_tx_weight); int packets;
while (qdisc_restart(q, &packets)) {