[PATCH AUTOSEL 6.12 429/486] net-sysfs: remove rtnl_trylock from queue attributes

[Sasha Levin <sashal@kernel.org>]

From: Antoine Tenart <atenart@kernel.org>

[ Upstream commit b0b6fcfa6ad8433e22b050c72cfbeec2548744b9 ]

Similar to the commit removing remove rtnl_trylock from device
attributes we here apply the same technique to networking queues.

Signed-off-by: Antoine Tenart <atenart@kernel.org>
Link: https://patch.msgid.link/20250204170314.146022-5-atenart@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/core/net-sysfs.c | 147 ++++++++++++++++++++++++++-----------------
 1 file changed, 89 insertions(+), 58 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 05cf5347f25e8..b398a2e0c243d 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1213,9 +1213,11 @@ static int net_rx_queue_change_owner(struct net_device *dev, int num,
  */
 struct netdev_queue_attribute {
 	struct attribute attr;
-	ssize_t (*show)(struct netdev_queue *queue, char *buf);
-	ssize_t (*store)(struct netdev_queue *queue,
-			 const char *buf, size_t len);
+	ssize_t (*show)(struct kobject *kobj, struct attribute *attr,
+			struct netdev_queue *queue, char *buf);
+	ssize_t (*store)(struct kobject *kobj, struct attribute *attr,
+			 struct netdev_queue *queue, const char *buf,
+			 size_t len);
 };
 #define to_netdev_queue_attr(_attr) \
 	container_of(_attr, struct netdev_queue_attribute, attr)
@@ -1232,7 +1234,7 @@ static ssize_t netdev_queue_attr_show(struct kobject *kobj,
 	if (!attribute->show)
 		return -EIO;
 
-	return attribute->show(queue, buf);
+	return attribute->show(kobj, attr, queue, buf);
 }
 
 static ssize_t netdev_queue_attr_store(struct kobject *kobj,
@@ -1246,7 +1248,7 @@ static ssize_t netdev_queue_attr_store(struct kobject *kobj,
 	if (!attribute->store)
 		return -EIO;
 
-	return attribute->store(queue, buf, count);
+	return attribute->store(kobj, attr, queue, buf, count);
 }
 
 static const struct sysfs_ops netdev_queue_sysfs_ops = {
@@ -1254,7 +1256,8 @@ static const struct sysfs_ops netdev_queue_sysfs_ops = {
 	.store = netdev_queue_attr_store,
 };
 
-static ssize_t tx_timeout_show(struct netdev_queue *queue, char *buf)
+static ssize_t tx_timeout_show(struct kobject *kobj, struct attribute *attr,
+			       struct netdev_queue *queue, char *buf)
 {
 	unsigned long trans_timeout = atomic_long_read(&queue->trans_timeout);
 
@@ -1272,18 +1275,18 @@ static unsigned int get_netdev_queue_index(struct netdev_queue *queue)
 	return i;
 }
 
-static ssize_t traffic_class_show(struct netdev_queue *queue,
-				  char *buf)
+static ssize_t traffic_class_show(struct kobject *kobj, struct attribute *attr,
+				  struct netdev_queue *queue, char *buf)
 {
 	struct net_device *dev = queue->dev;
-	int num_tc, tc;
-	int index;
+	int num_tc, tc, index, ret;
 
 	if (!netif_is_multiqueue(dev))
 		return -ENOENT;
 
-	if (!rtnl_trylock())
-		return restart_syscall();
+	ret = sysfs_rtnl_lock(kobj, attr, queue->dev);
+	if (ret)
+		return ret;
 
 	index = get_netdev_queue_index(queue);
 
@@ -1310,24 +1313,25 @@ static ssize_t traffic_class_show(struct netdev_queue *queue,
 }
 
 #ifdef CONFIG_XPS
-static ssize_t tx_maxrate_show(struct netdev_queue *queue,
-			       char *buf)
+static ssize_t tx_maxrate_show(struct kobject *kobj, struct attribute *attr,
+			       struct netdev_queue *queue, char *buf)
 {
 	return sysfs_emit(buf, "%lu\n", queue->tx_maxrate);
 }
 
-static ssize_t tx_maxrate_store(struct netdev_queue *queue,
-				const char *buf, size_t len)
+static ssize_t tx_maxrate_store(struct kobject *kobj, struct attribute *attr,
+				struct netdev_queue *queue, const char *buf,
+				size_t len)
 {
-	struct net_device *dev = queue->dev;
 	int err, index = get_netdev_queue_index(queue);
+	struct net_device *dev = queue->dev;
 	u32 rate = 0;
 
 	if (!capable(CAP_NET_ADMIN))
 		return -EPERM;
 
 	/* The check is also done later; this helps returning early without
-	 * hitting the trylock/restart below.
+	 * hitting the locking section below.
 	 */
 	if (!dev->netdev_ops->ndo_set_tx_maxrate)
 		return -EOPNOTSUPP;
@@ -1336,18 +1340,21 @@ static ssize_t tx_maxrate_store(struct netdev_queue *queue,
 	if (err < 0)
 		return err;
 
-	if (!rtnl_trylock())
-		return restart_syscall();
+	err = sysfs_rtnl_lock(kobj, attr, dev);
+	if (err)
+		return err;
 
 	err = -EOPNOTSUPP;
 	if (dev->netdev_ops->ndo_set_tx_maxrate)
 		err = dev->netdev_ops->ndo_set_tx_maxrate(dev, index, rate);
 
-	rtnl_unlock();
 	if (!err) {
 		queue->tx_maxrate = rate;
+		rtnl_unlock();
 		return len;
 	}
+
+	rtnl_unlock();
 	return err;
 }
 
@@ -1391,16 +1398,17 @@ static ssize_t bql_set(const char *buf, const size_t count,
 	return count;
 }
 
-static ssize_t bql_show_hold_time(struct netdev_queue *queue,
-				  char *buf)
+static ssize_t bql_show_hold_time(struct kobject *kobj, struct attribute *attr,
+				  struct netdev_queue *queue, char *buf)
 {
 	struct dql *dql = &queue->dql;
 
 	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(dql->slack_hold_time));
 }
 
-static ssize_t bql_set_hold_time(struct netdev_queue *queue,
-				 const char *buf, size_t len)
+static ssize_t bql_set_hold_time(struct kobject *kobj, struct attribute *attr,
+				 struct netdev_queue *queue, const char *buf,
+				 size_t len)
 {
 	struct dql *dql = &queue->dql;
 	unsigned int value;
@@ -1419,15 +1427,17 @@ static struct netdev_queue_attribute bql_hold_time_attribute __ro_after_init
 	= __ATTR(hold_time, 0644,
 		 bql_show_hold_time, bql_set_hold_time);
 
-static ssize_t bql_show_stall_thrs(struct netdev_queue *queue, char *buf)
+static ssize_t bql_show_stall_thrs(struct kobject *kobj, struct attribute *attr,
+				   struct netdev_queue *queue, char *buf)
 {
 	struct dql *dql = &queue->dql;
 
 	return sysfs_emit(buf, "%u\n", jiffies_to_msecs(dql->stall_thrs));
 }
 
-static ssize_t bql_set_stall_thrs(struct netdev_queue *queue,
-				  const char *buf, size_t len)
+static ssize_t bql_set_stall_thrs(struct kobject *kobj, struct attribute *attr,
+				  struct netdev_queue *queue, const char *buf,
+				  size_t len)
 {
 	struct dql *dql = &queue->dql;
 	unsigned int value;
@@ -1453,13 +1463,15 @@ static ssize_t bql_set_stall_thrs(struct netdev_queue *queue,
 static struct netdev_queue_attribute bql_stall_thrs_attribute __ro_after_init =
 	__ATTR(stall_thrs, 0644, bql_show_stall_thrs, bql_set_stall_thrs);
 
-static ssize_t bql_show_stall_max(struct netdev_queue *queue, char *buf)
+static ssize_t bql_show_stall_max(struct kobject *kobj, struct attribute *attr,
+				  struct netdev_queue *queue, char *buf)
 {
 	return sysfs_emit(buf, "%u\n", READ_ONCE(queue->dql.stall_max));
 }
 
-static ssize_t bql_set_stall_max(struct netdev_queue *queue,
-				 const char *buf, size_t len)
+static ssize_t bql_set_stall_max(struct kobject *kobj, struct attribute *attr,
+				 struct netdev_queue *queue, const char *buf,
+				 size_t len)
 {
 	WRITE_ONCE(queue->dql.stall_max, 0);
 	return len;
@@ -1468,7 +1480,8 @@ static ssize_t bql_set_stall_max(struct netdev_queue *queue,
 static struct netdev_queue_attribute bql_stall_max_attribute __ro_after_init =
 	__ATTR(stall_max, 0644, bql_show_stall_max, bql_set_stall_max);
 
-static ssize_t bql_show_stall_cnt(struct netdev_queue *queue, char *buf)
+static ssize_t bql_show_stall_cnt(struct kobject *kobj, struct attribute *attr,
+				  struct netdev_queue *queue, char *buf)
 {
 	struct dql *dql = &queue->dql;
 
@@ -1478,8 +1491,8 @@ static ssize_t bql_show_stall_cnt(struct netdev_queue *queue, char *buf)
 static struct netdev_queue_attribute bql_stall_cnt_attribute __ro_after_init =
 	__ATTR(stall_cnt, 0444, bql_show_stall_cnt, NULL);
 
-static ssize_t bql_show_inflight(struct netdev_queue *queue,
-				 char *buf)
+static ssize_t bql_show_inflight(struct kobject *kobj, struct attribute *attr,
+				 struct netdev_queue *queue, char *buf)
 {
 	struct dql *dql = &queue->dql;
 
@@ -1490,13 +1503,16 @@ static struct netdev_queue_attribute bql_inflight_attribute __ro_after_init =
 	__ATTR(inflight, 0444, bql_show_inflight, NULL);
 
 #define BQL_ATTR(NAME, FIELD)						\
-static ssize_t bql_show_ ## NAME(struct netdev_queue *queue,		\
-				 char *buf)				\
+static ssize_t bql_show_ ## NAME(struct kobject *kobj,			\
+				 struct attribute *attr,		\
+				 struct netdev_queue *queue, char *buf)	\
 {									\
 	return bql_show(buf, queue->dql.FIELD);				\
 }									\
 									\
-static ssize_t bql_set_ ## NAME(struct netdev_queue *queue,		\
+static ssize_t bql_set_ ## NAME(struct kobject *kobj,			\
+				struct attribute *attr,			\
+				struct netdev_queue *queue,		\
 				const char *buf, size_t len)		\
 {									\
 	return bql_set(buf, len, &queue->dql.FIELD);			\
@@ -1582,19 +1598,21 @@ static ssize_t xps_queue_show(struct net_device *dev, unsigned int index,
 	return len < PAGE_SIZE ? len : -EINVAL;
 }
 
-static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf)
+static ssize_t xps_cpus_show(struct kobject *kobj, struct attribute *attr,
+			     struct netdev_queue *queue, char *buf)
 {
 	struct net_device *dev = queue->dev;
 	unsigned int index;
-	int len, tc;
+	int len, tc, ret;
 
 	if (!netif_is_multiqueue(dev))
 		return -ENOENT;
 
 	index = get_netdev_queue_index(queue);
 
-	if (!rtnl_trylock())
-		return restart_syscall();
+	ret = sysfs_rtnl_lock(kobj, attr, queue->dev);
+	if (ret)
+		return ret;
 
 	/* If queue belongs to subordinate dev use its map */
 	dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
@@ -1605,18 +1623,21 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf)
 		return -EINVAL;
 	}
 
-	/* Make sure the subordinate device can't be freed */
-	get_device(&dev->dev);
+	/* Increase the net device refcnt to make sure it won't be freed while
+	 * xps_queue_show is running.
+	 */
+	dev_hold(dev);
 	rtnl_unlock();
 
 	len = xps_queue_show(dev, index, tc, buf, XPS_CPUS);
 
-	put_device(&dev->dev);
+	dev_put(dev);
 	return len;
 }
 
-static ssize_t xps_cpus_store(struct netdev_queue *queue,
-			      const char *buf, size_t len)
+static ssize_t xps_cpus_store(struct kobject *kobj, struct attribute *attr,
+			      struct netdev_queue *queue, const char *buf,
+			      size_t len)
 {
 	struct net_device *dev = queue->dev;
 	unsigned int index;
@@ -1640,9 +1661,10 @@ static ssize_t xps_cpus_store(struct netdev_queue *queue,
 		return err;
 	}
 
-	if (!rtnl_trylock()) {
+	err = sysfs_rtnl_lock(kobj, attr, dev);
+	if (err) {
 		free_cpumask_var(mask);
-		return restart_syscall();
+		return err;
 	}
 
 	err = netif_set_xps_queue(dev, mask, index);
@@ -1656,26 +1678,34 @@ static ssize_t xps_cpus_store(struct netdev_queue *queue,
 static struct netdev_queue_attribute xps_cpus_attribute __ro_after_init
 	= __ATTR_RW(xps_cpus);
 
-static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf)
+static ssize_t xps_rxqs_show(struct kobject *kobj, struct attribute *attr,
+			     struct netdev_queue *queue, char *buf)
 {
 	struct net_device *dev = queue->dev;
 	unsigned int index;
-	int tc;
+	int tc, ret;
 
 	index = get_netdev_queue_index(queue);
 
-	if (!rtnl_trylock())
-		return restart_syscall();
+	ret = sysfs_rtnl_lock(kobj, attr, dev);
+	if (ret)
+		return ret;
 
 	tc = netdev_txq_to_tc(dev, index);
+
+	/* Increase the net device refcnt to make sure it won't be freed while
+	 * xps_queue_show is running.
+	 */
+	dev_hold(dev);
 	rtnl_unlock();
-	if (tc < 0)
-		return -EINVAL;
 
-	return xps_queue_show(dev, index, tc, buf, XPS_RXQS);
+	ret = tc >= 0 ? xps_queue_show(dev, index, tc, buf, XPS_RXQS) : -EINVAL;
+	dev_put(dev);
+	return ret;
 }
 
-static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,
+static ssize_t xps_rxqs_store(struct kobject *kobj, struct attribute *attr,
+			      struct netdev_queue *queue, const char *buf,
 			      size_t len)
 {
 	struct net_device *dev = queue->dev;
@@ -1699,9 +1729,10 @@ static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,
 		return err;
 	}
 
-	if (!rtnl_trylock()) {
+	err = sysfs_rtnl_lock(kobj, attr, dev);
+	if (err) {
 		bitmap_free(mask);
-		return restart_syscall();
+		return err;
 	}
 
 	cpus_read_lock();
-- 
2.39.5