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authorJakub Kicinski <kuba@kernel.org>2021-10-30 10:18:51 -0700
committerDavid S. Miller <davem@davemloft.net>2021-11-01 13:26:07 +0000
commit1af0a0948e28d83bcfa9d48cd0f992f616c5d62e (patch)
treebd94424fa9d4bf6788edba77057a6822f3007d14 /net
parent46db1b77cd4f082c4e908c8f8086a2f7aae28b62 (diff)
ethtool: don't drop the rtnl_lock half way thru the ioctl
devlink compat code needs to drop rtnl_lock to take devlink->lock to ensure correct lock ordering. This is problematic because we're not strictly guaranteed that the netdev will not disappear after we re-lock. It may open a possibility of nested ->begin / ->complete calls. Instead of calling into devlink under rtnl_lock take a ref on the devlink instance and make the call after we've dropped rtnl_lock. We (continue to) assume that netdevs have an implicit reference on the devlink returned from ndo_get_devlink_port Note that ndo_get_devlink_port will now get called under rtnl_lock. That should be fine since none of the drivers seem to be taking serious locks inside ndo_get_devlink_port. Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/devlink.c45
-rw-r--r--net/ethtool/ioctl.c36
2 files changed, 39 insertions, 42 deletions
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 100d87fd3f65..6b5ee862429e 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -11283,55 +11283,28 @@ static struct devlink_port *netdev_to_devlink_port(struct net_device *dev)
return dev->netdev_ops->ndo_get_devlink_port(dev);
}
-static struct devlink *netdev_to_devlink(struct net_device *dev)
-{
- struct devlink_port *devlink_port = netdev_to_devlink_port(dev);
-
- if (!devlink_port)
- return NULL;
-
- return devlink_port->devlink;
-}
-
-void devlink_compat_running_version(struct net_device *dev,
+void devlink_compat_running_version(struct devlink *devlink,
char *buf, size_t len)
{
- struct devlink *devlink;
-
- dev_hold(dev);
- rtnl_unlock();
-
- devlink = netdev_to_devlink(dev);
- if (!devlink || !devlink->ops->info_get)
- goto out;
+ if (!devlink->ops->info_get)
+ return;
mutex_lock(&devlink->lock);
__devlink_compat_running_version(devlink, buf, len);
mutex_unlock(&devlink->lock);
-
-out:
- rtnl_lock();
- dev_put(dev);
}
-int devlink_compat_flash_update(struct net_device *dev, const char *file_name)
+int devlink_compat_flash_update(struct devlink *devlink, const char *file_name)
{
struct devlink_flash_update_params params = {};
- struct devlink *devlink;
int ret;
- dev_hold(dev);
- rtnl_unlock();
-
- devlink = netdev_to_devlink(dev);
- if (!devlink || !devlink->ops->flash_update) {
- ret = -EOPNOTSUPP;
- goto out;
- }
+ if (!devlink->ops->flash_update)
+ return -EOPNOTSUPP;
ret = request_firmware(&params.fw, file_name, devlink->dev);
if (ret)
- goto out;
+ return ret;
mutex_lock(&devlink->lock);
devlink_flash_update_begin_notify(devlink);
@@ -11341,10 +11314,6 @@ int devlink_compat_flash_update(struct net_device *dev, const char *file_name)
release_firmware(params.fw);
-out:
- rtnl_lock();
- dev_put(dev);
-
return ret;
}
diff --git a/net/ethtool/ioctl.c b/net/ethtool/ioctl.c
index 1980e37b6472..65e9bc1058b5 100644
--- a/net/ethtool/ioctl.c
+++ b/net/ethtool/ioctl.c
@@ -34,12 +34,27 @@
/* State held across locks and calls for commands which have devlink fallback */
struct ethtool_devlink_compat {
+ struct devlink *devlink;
union {
struct ethtool_flash efl;
struct ethtool_drvinfo info;
};
};
+static struct devlink *netdev_to_devlink_get(struct net_device *dev)
+{
+ struct devlink_port *devlink_port;
+
+ if (!dev->netdev_ops->ndo_get_devlink_port)
+ return NULL;
+
+ devlink_port = dev->netdev_ops->ndo_get_devlink_port(dev);
+ if (!devlink_port)
+ return NULL;
+
+ return devlink_try_get(devlink_port->devlink);
+}
+
/*
* Some useful ethtool_ops methods that're device independent.
* If we find that all drivers want to do the same thing here,
@@ -751,8 +766,8 @@ ethtool_get_drvinfo(struct net_device *dev, struct ethtool_devlink_compat *rsp)
rsp->info.eedump_len = ops->get_eeprom_len(dev);
if (!rsp->info.fw_version[0])
- devlink_compat_running_version(dev, rsp->info.fw_version,
- sizeof(rsp->info.fw_version));
+ rsp->devlink = netdev_to_devlink_get(dev);
+
return 0;
}
@@ -2184,8 +2199,10 @@ static int ethtool_set_value(struct net_device *dev, char __user *useraddr,
static int
ethtool_flash_device(struct net_device *dev, struct ethtool_devlink_compat *req)
{
- if (!dev->ethtool_ops->flash_device)
- return devlink_compat_flash_update(dev, req->efl.data);
+ if (!dev->ethtool_ops->flash_device) {
+ req->devlink = netdev_to_devlink_get(dev);
+ return 0;
+ }
return dev->ethtool_ops->flash_device(dev, &req->efl);
}
@@ -3027,7 +3044,16 @@ int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
goto exit_free;
switch (ethcmd) {
+ case ETHTOOL_FLASHDEV:
+ if (state->devlink)
+ rc = devlink_compat_flash_update(state->devlink,
+ state->efl.data);
+ break;
case ETHTOOL_GDRVINFO:
+ if (state->devlink)
+ devlink_compat_running_version(state->devlink,
+ state->info.fw_version,
+ sizeof(state->info.fw_version));
if (copy_to_user(useraddr, &state->info, sizeof(state->info))) {
rc = -EFAULT;
goto exit_free;
@@ -3036,6 +3062,8 @@ int dev_ethtool(struct net *net, struct ifreq *ifr, void __user *useraddr)
}
exit_free:
+ if (state->devlink)
+ devlink_put(state->devlink);
kfree(state);
return rc;
}