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Message-ID: <20241017183140.43028-4-kuniyu@amazon.com>
Date: Thu, 17 Oct 2024 11:31:34 -0700
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, Eric Dumazet
<edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni
<pabeni@...hat.com>, Remi Denis-Courmont <courmisch@...il.com>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v1 net-next 3/9] 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@...zon.com>
---
include/net/phonet/pn_dev.h | 3 ++-
net/phonet/pn_dev.c | 26 +++++++++++++++++---------
2 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/include/net/phonet/pn_dev.h b/include/net/phonet/pn_dev.h
index 6b2102b4ece3..ac0331d83a81 100644
--- a/include/net/phonet/pn_dev.h
+++ b/include/net/phonet/pn_dev.h
@@ -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);
diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c
index 2e7d850dc726..545279ef5910 100644
--- a/net/phonet/pn_dev.c
+++ b/net/phonet/pn_dev.c
@@ -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;
}
--
2.39.5 (Apple Git-154)
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