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phonet: Convert phonet_device_list.lock to spinlock_t. 

addr_doit() calls phonet_address_add() or phonet_address_del()
for RTM_NEWADDR or RTM_DELADDR, respectively.

Both functions only touch phonet_device_list(dev_net(dev)),
which is currently protected by RTNL and its dedicated mutex,
phonet_device_list.lock.

We will convert addr_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 11:31:34 -07:00 committed by Paolo Abeni
parent 68ed5c38b5
commit 42f5fe1dc4
2 changed files with 19 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/phonet/pn_dev.h
View File

@ -12,12 +12,13 @@
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
struct net;
struct phonet_device_list {
struct list_head list;
struct mutex lock;
spinlock_t lock;
};
struct phonet_device_list *phonet_device_list(struct net *net);

26
net/phonet/pn_dev.c
View File

@ -54,7 +54,7 @@ static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
pnd->netdev = dev;
bitmap_zero(pnd->addrs, 64);
BUG_ON(!mutex_is_locked(&pndevs->lock));
lockdep_assert_held(&pndevs->lock);
list_add_rcu(&pnd->list, &pndevs->list);
return pnd;
}
@ -64,7 +64,8 @@ static struct phonet_device *__phonet_get(struct net_device *dev)
struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
struct phonet_device *pnd;
BUG_ON(!mutex_is_locked(&pndevs->lock));
lockdep_assert_held(&pndevs->lock);
list_for_each_entry(pnd, &pndevs->list, list) {
if (pnd->netdev == dev)
return pnd;
@ -91,11 +92,13 @@ static void phonet_device_destroy(struct net_device *dev)
ASSERT_RTNL();
mutex_lock(&pndevs->lock);
spin_lock(&pndevs->lock);
pnd = __phonet_get(dev);
if (pnd)
list_del_rcu(&pnd->list);
mutex_unlock(&pndevs->lock);
spin_unlock(&pndevs->lock);
if (pnd) {
struct net *net = dev_net(dev);
@ -136,7 +139,8 @@ int phonet_address_add(struct net_device *dev, u8 addr)
struct phonet_device *pnd;
int err = 0;
mutex_lock(&pndevs->lock);
spin_lock(&pndevs->lock);
/* Find or create Phonet-specific device data */
pnd = __phonet_get(dev);
if (pnd == NULL)
@ -145,7 +149,9 @@ int phonet_address_add(struct net_device *dev, u8 addr)
err = -ENOMEM;
else if (test_and_set_bit(addr >> 2, pnd->addrs))
err = -EEXIST;
mutex_unlock(&pndevs->lock);
spin_unlock(&pndevs->lock);
return err;
}
@ -155,7 +161,8 @@ int phonet_address_del(struct net_device *dev, u8 addr)
struct phonet_device *pnd;
int err = 0;
mutex_lock(&pndevs->lock);
spin_lock(&pndevs->lock);
pnd = __phonet_get(dev);
if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
err = -EADDRNOTAVAIL;
@ -164,7 +171,8 @@ int phonet_address_del(struct net_device *dev, u8 addr)
list_del_rcu(&pnd->list);
else
pnd = NULL;
mutex_unlock(&pndevs->lock);
spin_unlock(&pndevs->lock);
if (pnd)
kfree_rcu(pnd, rcu);
@ -313,7 +321,7 @@ static int __net_init phonet_init_net(struct net *net)
return -ENOMEM;
INIT_LIST_HEAD(&pnn->pndevs.list);
mutex_init(&pnn->pndevs.lock);
spin_lock_init(&pnn->pndevs.lock);
mutex_init(&pnn->routes.lock);
return 0;
}