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net: iface: Introduce TX mutex locking

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A recent iface lock removal in ed17320c3d
exposed issues with concurrent access on TX to drivers that are not
re-entrant.

Reverting that commit does not really solve the problem, as it would
still exist if multiple Traffic Class queues are in use.

Therefore, introduce a separate mutex for TX data path, protecting the
L2/driver from concurrent transfers from several threads.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2023-11-10 10:23:34 +01:00 committed by Carles Cufí
parent 250ff71c64
commit 61c392c5b1
3 changed files with 34 additions and 0 deletions
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29
include/zephyr/net/net_if.h
View file

@ -212,6 +212,9 @@ enum net_if_flag {
/** IPv6 Multicast Listener Discovery disabled. */
NET_IF_IPV6_NO_MLD,
/** Mutex locking on TX data path disabled on the interface. */
NET_IF_NO_TX_LOCK,
/** @cond INTERNAL_HIDDEN */
/* Total number of flags - must be at the end of the enum */
NET_IF_NUM_FLAGS
@ -613,6 +616,7 @@ struct net_if {
#endif
struct k_mutex lock;
struct k_mutex tx_lock;
};
static inline void net_if_lock(struct net_if *iface)
@ -629,6 +633,31 @@ static inline void net_if_unlock(struct net_if *iface)
k_mutex_unlock(&iface->lock);
}
static inline bool net_if_flag_is_set(struct net_if *iface,
enum net_if_flag value);
static inline void net_if_tx_lock(struct net_if *iface)
{
NET_ASSERT(iface);
if (net_if_flag_is_set(iface, NET_IF_NO_TX_LOCK)) {
return;
}
(void)k_mutex_lock(&iface->tx_lock, K_FOREVER);
}
static inline void net_if_tx_unlock(struct net_if *iface)
{
NET_ASSERT(iface);
if (net_if_flag_is_set(iface, NET_IF_NO_TX_LOCK)) {
return;
}
k_mutex_unlock(&iface->tx_lock);
}
/**
* @brief Set a value in network interface flags
*

3
subsys/net/ip/net_if.c
View file

@ -254,7 +254,9 @@ static bool net_if_tx(struct net_if *iface, struct net_pkt *pkt)
}
}
net_if_tx_lock(iface);
status = net_if_l2(iface)->send(iface, pkt);
net_if_tx_unlock(iface);
if (IS_ENABLED(CONFIG_NET_PKT_TXTIME_STATS)) {
uint32_t end_tick = k_cycle_get_32();
@ -426,6 +428,7 @@ static inline void init_iface(struct net_if *iface)
#endif
k_mutex_init(&iface->lock);
k_mutex_init(&iface->tx_lock);
api->init(iface);
}

2
subsys/net/l2/ethernet/arp.c
View file

@ -534,7 +534,9 @@ static void arp_update(struct net_if *iface,
* the pkt are not counted twice and the packet filter
* callbacks are only called once.
*/
net_if_tx_lock(iface);
ret = net_if_l2(iface)->send(iface, pkt);
net_if_tx_unlock(iface);
if (ret < 0) {
net_pkt_unref(pkt);
}