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Message-ID: <20241017183140.43028-9-kuniyu@amazon.com>
Date: Thu, 17 Oct 2024 11:31:39 -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 8/9] phonet: Convert phonet_routes.lock to spinlock_t.
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@...zon.com>
---
include/net/phonet/pn_dev.h | 1 -
net/phonet/pn_dev.c | 23 ++++++++++++++---------
2 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/include/net/phonet/pn_dev.h b/include/net/phonet/pn_dev.h
index 021e524fd20a..37a3e83531c6 100644
--- a/include/net/phonet/pn_dev.h
+++ b/include/net/phonet/pn_dev.h
@@ -11,7 +11,6 @@
#define PN_DEV_H
#include <linux/list.h>
-#include <linux/mutex.h>
#include <linux/spinlock.h>
struct net;
diff --git a/net/phonet/pn_dev.c b/net/phonet/pn_dev.c
index 6ded0d347b9f..19234d664c4f 100644
--- a/net/phonet/pn_dev.c
+++ b/net/phonet/pn_dev.c
@@ -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;
--
2.39.5 (Apple Git-154)
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