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phonet: Convert phonet_routes.lock to spinlock_t.

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route_doit() calls phonet_route_add() or phonet_route_del()
for RTM_NEWROUTE or RTM_DELROUTE, respectively.

Both functions only touch phonet_pernet(dev_net(dev))->routes,
which is currently protected by RTNL and its dedicated mutex,
phonet_routes.lock.

We will convert route_doit() to RCU and cannot use mutex inside RCU.

Let's convert the mutex to spinlock_t.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Kuniyuki Iwashima 2024-10-17 11:31:39 -07:00 committed by Paolo Abeni
parent de51ad08b1
commit 3deec3b4af
2 changed files with 14 additions and 10 deletions
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1
include/net/phonet/pn_dev.h
View File

@ -11,7 +11,6 @@
#define PN_DEV_H
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
struct net;

23
net/phonet/pn_dev.c
View File

@ -22,7 +22,7 @@
#include <net/phonet/pn_dev.h>
struct phonet_routes {
struct mutex lock;
spinlock_t lock;
struct net_device __rcu *table[64];
};
@ -273,13 +273,15 @@ static void phonet_route_autodel(struct net_device *dev)
/* Remove left-over Phonet routes */
bitmap_zero(deleted, 64);
mutex_lock(&pnn->routes.lock);
for (i = 0; i < 64; i++)
spin_lock(&pnn->routes.lock);
for (i = 0; i < 64; i++) {
if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
RCU_INIT_POINTER(pnn->routes.table[i], NULL);
set_bit(i, deleted);
}
mutex_unlock(&pnn->routes.lock);
}
spin_unlock(&pnn->routes.lock);
if (bitmap_empty(deleted, 64))
return; /* short-circuit RCU */
@ -326,7 +328,7 @@ static int __net_init phonet_init_net(struct net *net)
INIT_LIST_HEAD(&pnn->pndevs.list);
spin_lock_init(&pnn->pndevs.lock);
mutex_init(&pnn->routes.lock);
spin_lock_init(&pnn->routes.lock);
return 0;
}
@ -376,13 +378,15 @@ int phonet_route_add(struct net_device *dev, u8 daddr)
int err = -EEXIST;
daddr = daddr >> 2;
mutex_lock(&routes->lock);
spin_lock(&routes->lock);
if (routes->table[daddr] == NULL) {
rcu_assign_pointer(routes->table[daddr], dev);
dev_hold(dev);
err = 0;
}
mutex_unlock(&routes->lock);
spin_unlock(&routes->lock);
return err;
}
@ -392,12 +396,13 @@ int phonet_route_del(struct net_device *dev, u8 daddr)
struct phonet_routes *routes = &pnn->routes;
daddr = daddr >> 2;
mutex_lock(&routes->lock);
spin_lock(&routes->lock);
if (rcu_access_pointer(routes->table[daddr]) == dev)
RCU_INIT_POINTER(routes->table[daddr], NULL);
else
dev = NULL;
mutex_unlock(&routes->lock);
spin_unlock(&routes->lock);
if (!dev)
return -ENOENT;