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Date: Tue, 28 Sep 2021 14:55:00 +0200
From: Antoine Tenart <atenart@...nel.org>
To: davem@...emloft.net, kuba@...nel.org
Cc: Antoine Tenart <atenart@...nel.org>, pabeni@...hat.com,
gregkh@...uxfoundation.org, ebiederm@...ssion.com,
stephen@...workplumber.org, herbert@...dor.apana.org.au,
juri.lelli@...hat.com, netdev@...r.kernel.org
Subject: [RFC PATCH net-next 9/9] net-sysfs: remove the use of rtnl_trylock/restart_syscall
The ABBA deadlock avoided by using rtnl_trylock and restart_syscall was
fixed in previous commits, we can now remove the use of this
trylock/restart logic and have net-sysfs operations not spinning when
rtnl is already taken.
Signed-off-by: Antoine Tenart <atenart@...nel.org>
---
net/core/net-sysfs.c | 95 +++++++-------------------------------------
1 file changed, 14 insertions(+), 81 deletions(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index e754f00c117b..987b32fd8604 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -90,9 +90,7 @@ static ssize_t netdev_store(struct device *dev, struct device_attribute *attr,
if (ret)
goto err;
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev)) {
ret = (*set)(netdev, new);
if (ret == 0)
@@ -196,15 +194,7 @@ static ssize_t speed_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
int ret = -EINVAL;
- /* The check is also done in __ethtool_get_link_ksettings; this helps
- * returning early without hitting the trylock/restart below.
- */
- if (!netdev->ethtool_ops->get_link_ksettings)
- return -EOPNOTSUPP;
-
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (netif_running(netdev)) {
struct ethtool_link_ksettings cmd;
@@ -222,15 +212,7 @@ static ssize_t duplex_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
int ret = -EINVAL;
- /* The check is also done in __ethtool_get_link_ksettings; this helps
- * returning early without hitting the trylock/restart below.
- */
- if (!netdev->ethtool_ops->get_link_ksettings)
- return -EOPNOTSUPP;
-
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (netif_running(netdev)) {
struct ethtool_link_ksettings cmd;
@@ -427,9 +409,7 @@ static ssize_t ifalias_store(struct device *dev, struct device_attribute *attr,
if (len > 0 && buf[len - 1] == '\n')
--count;
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev)) {
ret = dev_set_alias(netdev, buf, count);
if (ret < 0)
@@ -490,15 +470,7 @@ static ssize_t phys_port_id_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
ssize_t ret = -EINVAL;
- /* The check is also done in dev_get_phys_port_id; this helps returning
- * early without hitting the trylock/restart below.
- */
- if (!netdev->netdev_ops->ndo_get_phys_port_id)
- return -EOPNOTSUPP;
-
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev)) {
struct netdev_phys_item_id ppid;
@@ -518,16 +490,7 @@ static ssize_t phys_port_name_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
ssize_t ret = -EINVAL;
- /* The checks are also done in dev_get_phys_port_name; this helps
- * returning early without hitting the trylock/restart below.
- */
- if (!netdev->netdev_ops->ndo_get_phys_port_name &&
- !netdev->netdev_ops->ndo_get_devlink_port)
- return -EOPNOTSUPP;
-
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev)) {
char name[IFNAMSIZ];
@@ -547,16 +510,7 @@ static ssize_t phys_switch_id_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
ssize_t ret = -EINVAL;
- /* The checks are also done in dev_get_phys_port_name; this helps
- * returning early without hitting the trylock/restart below.
- */
- if (!netdev->netdev_ops->ndo_get_port_parent_id &&
- !netdev->netdev_ops->ndo_get_devlink_port)
- return -EOPNOTSUPP;
-
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev)) {
struct netdev_phys_item_id ppid = { };
@@ -576,9 +530,7 @@ static ssize_t threaded_show(struct device *dev,
struct net_device *netdev = to_net_dev(dev);
ssize_t ret = -EINVAL;
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
if (dev_isalive(netdev))
ret = sprintf(buf, fmt_dec, netdev->threaded);
@@ -1214,9 +1166,7 @@ static ssize_t traffic_class_show(struct netdev_queue *queue,
if (!netif_is_multiqueue(dev))
return -ENOENT;
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
index = get_netdev_queue_index(queue);
/* If queue belongs to subordinate dev use its TC mapping */
@@ -1258,18 +1208,11 @@ static ssize_t tx_maxrate_store(struct netdev_queue *queue,
if (!capable(CAP_NET_ADMIN))
return -EPERM;
- /* The check is also done later; this helps returning early without
- * hitting the trylock/restart below.
- */
- if (!dev->netdev_ops->ndo_set_tx_maxrate)
- return -EOPNOTSUPP;
-
err = kstrtou32(buf, 10, &rate);
if (err < 0)
return err;
- if (!rtnl_trylock())
- return restart_syscall();
+ rtnl_lock();
err = -EOPNOTSUPP;
if (dev->netdev_ops->ndo_set_tx_maxrate)
@@ -1460,8 +1403,7 @@ static ssize_t xps_cpus_show(struct netdev_queue *queue, char *buf)
index = get_netdev_queue_index(queue);
- if (!rtnl_trylock())
- return restart_syscall();
+ rtnl_lock();
/* If queue belongs to subordinate dev use its map */
dev = netdev_get_tx_queue(dev, index)->sb_dev ? : dev;
@@ -1507,11 +1449,7 @@ static ssize_t xps_cpus_store(struct netdev_queue *queue,
return err;
}
- if (!rtnl_trylock()) {
- free_cpumask_var(mask);
- return restart_syscall();
- }
-
+ rtnl_lock();
err = netif_set_xps_queue(dev, mask, index);
rtnl_unlock();
@@ -1531,9 +1469,7 @@ static ssize_t xps_rxqs_show(struct netdev_queue *queue, char *buf)
index = get_netdev_queue_index(queue);
- if (!rtnl_trylock())
- return restart_syscall();
-
+ rtnl_lock();
tc = netdev_txq_to_tc(dev, index);
rtnl_unlock();
if (tc < 0)
@@ -1566,10 +1502,7 @@ static ssize_t xps_rxqs_store(struct netdev_queue *queue, const char *buf,
return err;
}
- if (!rtnl_trylock()) {
- bitmap_free(mask);
- return restart_syscall();
- }
+ rtnl_lock();
cpus_read_lock();
err = __netif_set_xps_queue(dev, mask, index, XPS_RXQS);
--
2.31.1
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