github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-10-15 20:30:02 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

net: add READ_ONCE()/WRITE_ONCE() annotations for dev->num_tc

Browse Source 
Several fast-path and control-path lockless readers access dev->num_tc
(e.g., skb_tx_hash(), netdev_txq_to_tc(), netdev_get_num_tc(), and
qdisc/driver lookups) while concurrent writers update dev->num_tc
during TC setup, device reset, or channel configuration.

Add READ_ONCE() and WRITE_ONCE() annotations to prevent compiler
reordering and load/store tearing when accessing dev->num_tc.

Update inline helpers in netdevice.h (netdev_get_num_tc(),
netdev_set_prio_tc_map(), and netdev_get_sb_channel()) as well as
writers and lockless readers in core networking code and drivers.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260812085440.3917924-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-08-12 08:54:39 +00:00 committed by Jakub Kicinski
parent 21ef2d065a
commit 0c6c32a8c8
12 changed files with 40 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/net/ethernet/chelsio/cxgb4/cxgb4_main.c
View File

@ -1163,7 +1163,7 @@ static u16 cxgb_select_queue(struct net_device *dev, struct sk_buff *skb,
}
#endif /* CONFIG_CHELSIO_T4_DCB */
if (dev->num_tc) {
if (netdev_get_num_tc(dev)) {
struct port_info *pi = netdev2pinfo(dev);
u8 ver, proto;

12
drivers/net/ethernet/freescale/dpaa2/dpaa2-eth.c
View File

@ -1403,10 +1403,10 @@ static netdev_tx_t __dpaa2_eth_tx(struct sk_buff *skb,
struct dpaa2_eth_fq *fq;
struct netdev_queue *nq;
struct dpaa2_fd *fd;
int err, i, num_tc;
u16 queue_mapping;
void *swa = NULL;
u8 prio = 0;
int err, i;
u32 fd_len;
percpu_stats = this_cpu_ptr(priv->percpu_stats);
@ -1468,12 +1468,14 @@ static netdev_tx_t __dpaa2_eth_tx(struct sk_buff *skb,
*/
queue_mapping = skb_get_queue_mapping(skb);
if (net_dev->num_tc) {
num_tc = netdev_get_num_tc(net_dev);
if (num_tc) {
prio = netdev_txq_to_tc(net_dev, queue_mapping);
/* Hardware interprets priority level 0 as being the highest,
* so we need to do a reverse mapping to the netdev tc index
*/
prio = net_dev->num_tc - prio - 1;
prio = num_tc - prio - 1;
/* We have only one FQ array entry for all Tx hardware queues
* with the same flow id (but different priority levels)
*/
@ -2913,7 +2915,7 @@ static int update_xps(struct dpaa2_eth_priv *priv)
return -ENOMEM;
num_queues = dpaa2_eth_queue_count(priv);
netdev_queues = (net_dev->num_tc ? : 1) * num_queues;
netdev_queues = (netdev_get_num_tc(net_dev) ? : 1) * num_queues;
/* The first <num_queues> entries in priv->fq array are Tx/Tx conf
* queues, so only process those
@ -2946,7 +2948,7 @@ static int dpaa2_eth_setup_mqprio(struct net_device *net_dev,
num_queues = dpaa2_eth_queue_count(priv);
num_tc = mqprio->num_tc;
if (num_tc == net_dev->num_tc)
if (num_tc == netdev_get_num_tc(net_dev))
return 0;
if (num_tc > dpaa2_eth_tc_count(priv)) {

2
drivers/net/ethernet/intel/igc/igc_tsn.c
View File

@ -182,7 +182,7 @@ static u32 igc_fpe_map_preempt_tc_to_queue(const struct igc_adapter *adapter,
struct net_device *dev = adapter->netdev;
u32 i, queue = 0;
for (i = 0; i < dev->num_tc; i++) {
for (i = 0; i < netdev_get_num_tc(dev); i++) {
struct netdev_tc_txq res;
u32 offset, count;

2
drivers/net/ethernet/mellanox/mlx5/core/en_main.c
View File

@ -3245,7 +3245,7 @@ static int mlx5e_update_tc_and_tx_queues(struct mlx5e_priv *priv)
int i;
old_num_txqs = netdev->real_num_tx_queues;
old_ntc = netdev->num_tc ? : 1;
old_ntc = netdev_get_num_tc(netdev) ? : 1;
for (i = 0; i < ARRAY_SIZE(old_tc_to_txq); i++)
old_tc_to_txq[i].combined = READ_ONCE(netdev->tc_to_txq[i].combined);

2
drivers/net/ethernet/sfc/falcon/net_driver.h
View File

@ -1208,7 +1208,7 @@ ef4_channel_get_tx_queue(struct ef4_channel *channel, unsigned type)
static inline bool ef4_tx_queue_used(struct ef4_tx_queue *tx_queue)
{
return !(tx_queue->efx->net_dev->num_tc < 2 &&
return !(netdev_get_num_tc(tx_queue->efx->net_dev) < 2 &&
tx_queue->queue & EF4_TXQ_TYPE_HIGHPRI);
}

8
drivers/net/ethernet/sfc/falcon/tx.c
View File

@ -435,7 +435,7 @@ int ef4_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
mqprio->hw = TC_MQPRIO_HW_OFFLOAD_TCS;
if (num_tc == net_dev->num_tc)
if (num_tc == netdev_get_num_tc(net_dev))
return 0;
for (tc = 0; tc < num_tc; tc++) {
@ -447,7 +447,7 @@ int ef4_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
WRITE_ONCE(net_dev->tc_to_txq[tc].combined, res.combined);
}
if (num_tc > net_dev->num_tc) {
if (num_tc > netdev_get_num_tc(net_dev)) {
/* Initialise high-priority queues as necessary */
ef4_for_each_channel(channel, efx) {
ef4_for_each_possible_channel_tx_queue(tx_queue,
@ -466,7 +466,7 @@ int ef4_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
}
} else {
/* Reduce number of classes before number of queues */
net_dev->num_tc = num_tc;
WRITE_ONCE(net_dev->num_tc, num_tc);
}
rc = netif_set_real_num_tx_queues(net_dev,
@ -481,7 +481,7 @@ int ef4_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
* it to ef4_fini_channels().
*/
net_dev->num_tc = num_tc;
WRITE_ONCE(net_dev->num_tc, num_tc);
return 0;
}

4
drivers/net/ethernet/sfc/siena/tx.c
View File

@ -376,7 +376,7 @@ int efx_siena_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
mqprio->hw = TC_MQPRIO_HW_OFFLOAD_TCS;
if (num_tc == net_dev->num_tc)
if (num_tc == netdev_get_num_tc(net_dev))
return 0;
for (tc = 0; tc < num_tc; tc++) {
@ -388,7 +388,7 @@ int efx_siena_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
WRITE_ONCE(net_dev->tc_to_txq[tc].combined, res.combined);
}
net_dev->num_tc = num_tc;
WRITE_ONCE(net_dev->num_tc, num_tc);
return netif_set_real_num_tx_queues(net_dev,
max_t(int, num_tc, 1) *

2
drivers/net/ethernet/ti/cpsw_priv.c
View File

@ -949,7 +949,7 @@ static int cpsw_set_cbs(struct net_device *ndev,
* limited first and for compliance with CPDMA rate limited channels
* that also used in bacward order. FIFO0 cannot be rate limited.
*/
fifo = cpsw_tc_to_fifo(tc, ndev->num_tc);
fifo = cpsw_tc_to_fifo(tc, netdev_get_num_tc(ndev));
if (!fifo) {
dev_err(priv->dev, "Last tc%d can't be rate limited", tc);
return -EINVAL;

8
include/linux/netdevice.h
View File

@ -2678,7 +2678,7 @@ int netdev_get_prio_tc_map(const struct net_device *dev, u32 prio)
static inline
int netdev_set_prio_tc_map(struct net_device *dev, u8 prio, u8 tc)
{
if (tc >= dev->num_tc)
if (tc >= READ_ONCE(dev->num_tc))
return -EINVAL;
dev->prio_tc_map[prio & TC_BITMASK] = tc & TC_BITMASK;
@ -2691,9 +2691,9 @@ int netdev_set_tc_queue(struct net_device *dev, u8 tc, u16 count, u16 offset);
int netdev_set_num_tc(struct net_device *dev, u8 num_tc);
static inline
int netdev_get_num_tc(struct net_device *dev)
int netdev_get_num_tc(const struct net_device *dev)
{
return dev->num_tc;
return READ_ONCE(dev->num_tc);
}
static inline void net_prefetch(void *p)
@ -2720,7 +2720,7 @@ int netdev_bind_sb_channel_queue(struct net_device *dev,
int netdev_set_sb_channel(struct net_device *dev, u16 channel);
static inline int netdev_get_sb_channel(struct net_device *dev)
{
return max_t(int, -dev->num_tc, 0);
return max_t(int, -READ_ONCE(dev->num_tc), 0);
}
static inline

25
net/core/dev.c
View File

@ -2660,7 +2660,7 @@ static void netif_setup_tc(struct net_device *dev, unsigned int txq)
/* If TC0 is invalidated disable TC mapping */
if (res.offset + res.count > txq) {
netdev_warn(dev, "Number of in use tx queues changed invalidating tc mappings. Priority traffic classification disabled!\n");
dev->num_tc = 0;
WRITE_ONCE(dev->num_tc, 0);
return;
}
@ -2679,7 +2679,7 @@ static void netif_setup_tc(struct net_device *dev, unsigned int txq)
int netdev_txq_to_tc(struct net_device *dev, unsigned int txq)
{
if (dev->num_tc) {
if (READ_ONCE(dev->num_tc)) {
struct netdev_tc_txq *tc = &dev->tc_to_txq[0];
int i;
@ -2881,18 +2881,19 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
u16 index, enum xps_map_type type)
{
struct xps_dev_maps *dev_maps, *new_dev_maps = NULL, *old_dev_maps = NULL;
int maps_sz, num_tc = 1, tc = 0, dev_num_tc;
const unsigned long *online_mask = NULL;
bool active = false, copy = false;
int i, j, tci, numa_node_id = -2;
int maps_sz, num_tc = 1, tc = 0;
struct xps_map *map, *new_map;
unsigned int nr_ids;
WARN_ON_ONCE(index >= dev->num_tx_queues);
if (dev->num_tc) {
dev_num_tc = READ_ONCE(dev->num_tc);
if (dev_num_tc) {
/* Do not allow XPS on subordinate device directly */
num_tc = dev->num_tc;
num_tc = dev_num_tc;
if (num_tc < 0)
return -EINVAL;
@ -3116,7 +3117,7 @@ void netdev_reset_tc(struct net_device *dev)
netdev_unbind_all_sb_channels(dev);
/* Reset TC configuration of device */
dev->num_tc = 0;
WRITE_ONCE(dev->num_tc, 0);
for (i = 0; i < TC_MAX_QUEUE; i++)
WRITE_ONCE(dev->tc_to_txq[i].combined, 0);
memset(dev->prio_tc_map, 0, sizeof(dev->prio_tc_map));
@ -3130,7 +3131,7 @@ int netdev_set_tc_queue(struct net_device *dev, u8 tc, u16 count, u16 offset)
.offset = offset,
};
if (tc >= dev->num_tc)
if (tc >= READ_ONCE(dev->num_tc))
return -EINVAL;
#ifdef CONFIG_XPS
@ -3151,7 +3152,7 @@ int netdev_set_num_tc(struct net_device *dev, u8 num_tc)
#endif
netdev_unbind_all_sb_channels(dev);
dev->num_tc = num_tc;
WRITE_ONCE(dev->num_tc, num_tc);
return 0;
}
EXPORT_SYMBOL(netdev_set_num_tc);
@ -3181,7 +3182,7 @@ int netdev_bind_sb_channel_queue(struct net_device *dev,
u8 tc, u16 count, u16 offset)
{
/* Make certain the sb_dev and dev are already configured */
if (sb_dev->num_tc >= 0 || tc >= dev->num_tc)
if (READ_ONCE(sb_dev->num_tc) >= 0 || tc >= READ_ONCE(dev->num_tc))
return -EINVAL;
/* We cannot hand out queues we don't have */
@ -3220,7 +3221,7 @@ int netdev_set_sb_channel(struct net_device *dev, u16 channel)
if (channel > S16_MAX)
return -EINVAL;
dev->num_tc = -channel;
WRITE_ONCE(dev->num_tc, -channel);
return 0;
}
@ -3249,7 +3250,7 @@ int netif_set_real_num_tx_queues(struct net_device *dev, unsigned int txq)
if (rc)
return rc;
if (dev->num_tc)
if (READ_ONCE(dev->num_tc))
netif_setup_tc(dev, txq);
net_shaper_set_real_num_tx_queues(dev, txq);
@ -3558,7 +3559,7 @@ static u16 skb_tx_hash(const struct net_device *dev,
u16 qoffset = 0;
u16 qcount = dev->real_num_tx_queues;
if (dev->num_tc) {
if (READ_ONCE(dev->num_tc)) {
u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
struct netdev_tc_txq res;

2
net/core/net-sysfs.c
View File

@ -1432,7 +1432,7 @@ static ssize_t traffic_class_show(struct kobject *kobj, struct attribute *attr,
/* If queue belongs to subordinate dev use its TC mapping */
dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
num_tc = dev->num_tc;
num_tc = READ_ONCE(dev->num_tc);
tc = netdev_txq_to_tc(dev, index);
rtnl_unlock();

7
net/sched/sch_taprio.c
View File

@ -1185,7 +1185,7 @@ static int taprio_parse_mqprio_opt(struct net_device *dev,
bool allow_overlapping_txqs = TXTIME_ASSIST_IS_ENABLED(taprio_flags);
if (!qopt) {
if (!dev->num_tc) {
if (!netdev_get_num_tc(dev)) {
NL_SET_ERR_MSG(extack, "'mqprio' configuration is necessary");
return -EINVAL;
}
@ -1439,9 +1439,10 @@ static void taprio_offload_config_changed(struct taprio_sched *q)
static u32 tc_map_to_queue_mask(struct net_device *dev, u32 tc_mask)
{
int num_tc = netdev_get_num_tc(dev);
u32 i, queue_mask = 0;
for (i = 0; i < dev->num_tc; i++) {
for (i = 0; i < num_tc; i++) {
struct netdev_tc_txq res;
if (!(tc_mask & BIT(i)))
@ -1799,7 +1800,7 @@ static int taprio_mqprio_cmp(const struct net_device *dev,
{
int i;
if (!mqprio || mqprio->num_tc != dev->num_tc)
if (!mqprio || mqprio->num_tc != netdev_get_num_tc(dev))
return -1;
for (i = 0; i < mqprio->num_tc; i++) {