From: Taehee Yoo <ap420073@gmail.com>
Date: Mon, 21 Oct 2019 18:47:56 +0000
Subject: net: core: add ignore flag to netdev_adjacent structure
Patch-mainline: v5.4-rc6
Git-commit: 32b6d34fedc2229cdf6a047fdbc0704085441915
References: bsc#1154353
In order to link an adjacent node, netdev_upper_dev_link() is used
and in order to unlink an adjacent node, netdev_upper_dev_unlink() is used.
unlink operation does not fail, but link operation can fail.
In order to exchange adjacent nodes, we should unlink an old adjacent
node first. then, link a new adjacent node.
If link operation is failed, we should link an old adjacent node again.
But this link operation can fail too.
It eventually breaks the adjacent link relationship.
This patch adds an ignore flag into the netdev_adjacent structure.
If this flag is set, netdev_upper_dev_link() ignores an old adjacent
node for a moment.
This patch also adds new functions for other modules.
netdev_adjacent_change_prepare()
netdev_adjacent_change_commit()
netdev_adjacent_change_abort()
netdev_adjacent_change_prepare() inserts new device into adjacent list
but new device is not allowed to use immediately.
If netdev_adjacent_change_prepare() fails, it internally rollbacks
adjacent list so that we don't need any other action.
netdev_adjacent_change_commit() deletes old device in the adjacent list
and allows new device to use.
netdev_adjacent_change_abort() rollbacks adjacent list.
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
include/linux/netdevice.h | 10 ++
net/core/dev.c | 230 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 219 insertions(+), 21 deletions(-)
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -4323,6 +4323,16 @@ int netdev_master_upper_dev_link(struct
struct netlink_ext_ack *extack);
void netdev_upper_dev_unlink(struct net_device *dev,
struct net_device *upper_dev);
+int netdev_adjacent_change_prepare(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev,
+ struct netlink_ext_ack *extack);
+void netdev_adjacent_change_commit(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev);
+void netdev_adjacent_change_abort(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev);
void netdev_adjacent_rename_links(struct net_device *dev, char *oldname);
void *netdev_lower_dev_get_private(struct net_device *dev,
struct net_device *lower_dev);
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6408,6 +6408,9 @@ struct netdev_adjacent {
/* upper master flag, there can only be one master device per list */
bool master;
+ /* lookup ignore flag */
+ bool ignore;
+
/* counter for the number of times this device was added to us */
u16 ref_nr;
@@ -6430,7 +6433,7 @@ static struct netdev_adjacent *__netdev_
return NULL;
}
-static int __netdev_has_upper_dev(struct net_device *upper_dev, void *data)
+static int ____netdev_has_upper_dev(struct net_device *upper_dev, void *data)
{
struct net_device *dev = data;
@@ -6451,7 +6454,7 @@ bool netdev_has_upper_dev(struct net_dev
{
ASSERT_RTNL();
- return netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,
+ return netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
upper_dev);
}
EXPORT_SYMBOL(netdev_has_upper_dev);
@@ -6469,7 +6472,7 @@ EXPORT_SYMBOL(netdev_has_upper_dev);
bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
struct net_device *upper_dev)
{
- return !!netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,
+ return !!netdev_walk_all_upper_dev_rcu(dev, ____netdev_has_upper_dev,
upper_dev);
}
EXPORT_SYMBOL(netdev_has_upper_dev_all_rcu);
@@ -6513,6 +6516,22 @@ struct net_device *netdev_master_upper_d
}
EXPORT_SYMBOL(netdev_master_upper_dev_get);
+static struct net_device *__netdev_master_upper_dev_get(struct net_device *dev)
+{
+ struct netdev_adjacent *upper;
+
+ ASSERT_RTNL();
+
+ if (list_empty(&dev->adj_list.upper))
+ return NULL;
+
+ upper = list_first_entry(&dev->adj_list.upper,
+ struct netdev_adjacent, list);
+ if (likely(upper->master) && !upper->ignore)
+ return upper->dev;
+ return NULL;
+}
+
/**
* netdev_has_any_lower_dev - Check if device is linked to some device
* @dev: device
@@ -6563,8 +6582,9 @@ struct net_device *netdev_upper_get_next
}
EXPORT_SYMBOL(netdev_upper_get_next_dev_rcu);
-static struct net_device *netdev_next_upper_dev(struct net_device *dev,
- struct list_head **iter)
+static struct net_device *__netdev_next_upper_dev(struct net_device *dev,
+ struct list_head **iter,
+ bool *ignore)
{
struct netdev_adjacent *upper;
@@ -6574,6 +6594,7 @@ static struct net_device *netdev_next_up
return NULL;
*iter = &upper->list;
+ *ignore = upper->ignore;
return upper->dev;
}
@@ -6595,14 +6616,15 @@ static struct net_device *netdev_next_up
return upper->dev;
}
-static int netdev_walk_all_upper_dev(struct net_device *dev,
- int (*fn)(struct net_device *dev,
- void *data),
- void *data)
+static int __netdev_walk_all_upper_dev(struct net_device *dev,
+ int (*fn)(struct net_device *dev,
+ void *data),
+ void *data)
{
struct net_device *udev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
int ret, cur = 0;
+ bool ignore;
now = dev;
iter = &dev->adj_list.upper;
@@ -6616,9 +6638,11 @@ static int netdev_walk_all_upper_dev(str
next = NULL;
while (1) {
- udev = netdev_next_upper_dev(now, &iter);
+ udev = __netdev_next_upper_dev(now, &iter, &ignore);
if (!udev)
break;
+ if (ignore)
+ continue;
next = udev;
niter = &udev->adj_list.upper;
@@ -6688,6 +6712,15 @@ int netdev_walk_all_upper_dev_rcu(struct
}
EXPORT_SYMBOL_GPL(netdev_walk_all_upper_dev_rcu);
+static bool __netdev_has_upper_dev(struct net_device *dev,
+ struct net_device *upper_dev)
+{
+ ASSERT_RTNL();
+
+ return __netdev_walk_all_upper_dev(dev, ____netdev_has_upper_dev,
+ upper_dev);
+}
+
/**
* netdev_lower_get_next_private - Get the next ->private from the
* lower neighbour list
@@ -6784,6 +6817,23 @@ static struct net_device *netdev_next_lo
return lower->dev;
}
+static struct net_device *__netdev_next_lower_dev(struct net_device *dev,
+ struct list_head **iter,
+ bool *ignore)
+{
+ struct netdev_adjacent *lower;
+
+ lower = list_entry((*iter)->next, struct netdev_adjacent, list);
+
+ if (&lower->list == &dev->adj_list.lower)
+ return NULL;
+
+ *iter = &lower->list;
+ *ignore = lower->ignore;
+
+ return lower->dev;
+}
+
int netdev_walk_all_lower_dev(struct net_device *dev,
int (*fn)(struct net_device *dev,
void *data),
@@ -6831,6 +6881,55 @@ int netdev_walk_all_lower_dev(struct net
}
EXPORT_SYMBOL_GPL(netdev_walk_all_lower_dev);
+static int __netdev_walk_all_lower_dev(struct net_device *dev,
+ int (*fn)(struct net_device *dev,
+ void *data),
+ void *data)
+{
+ struct net_device *ldev, *next, *now, *dev_stack[MAX_NEST_DEV + 1];
+ struct list_head *niter, *iter, *iter_stack[MAX_NEST_DEV + 1];
+ int ret, cur = 0;
+ bool ignore;
+
+ now = dev;
+ iter = &dev->adj_list.lower;
+
+ while (1) {
+ if (now != dev) {
+ ret = fn(now, data);
+ if (ret)
+ return ret;
+ }
+
+ next = NULL;
+ while (1) {
+ ldev = __netdev_next_lower_dev(now, &iter, &ignore);
+ if (!ldev)
+ break;
+ if (ignore)
+ continue;
+
+ next = ldev;
+ niter = &ldev->adj_list.lower;
+ dev_stack[cur] = now;
+ iter_stack[cur++] = iter;
+ break;
+ }
+
+ if (!next) {
+ if (!cur)
+ return 0;
+ next = dev_stack[--cur];
+ niter = iter_stack[cur];
+ }
+
+ now = next;
+ iter = niter;
+ }
+
+ return 0;
+}
+
static struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
struct list_head **iter)
{
@@ -6850,11 +6949,14 @@ static u8 __netdev_upper_depth(struct ne
struct net_device *udev;
struct list_head *iter;
u8 max_depth = 0;
+ bool ignore;
for (iter = &dev->adj_list.upper,
- udev = netdev_next_upper_dev(dev, &iter);
+ udev = __netdev_next_upper_dev(dev, &iter, &ignore);
udev;
- udev = netdev_next_upper_dev(dev, &iter)) {
+ udev = __netdev_next_upper_dev(dev, &iter, &ignore)) {
+ if (ignore)
+ continue;
if (max_depth < udev->upper_level)
max_depth = udev->upper_level;
}
@@ -6867,11 +6969,14 @@ static u8 __netdev_lower_depth(struct ne
struct net_device *ldev;
struct list_head *iter;
u8 max_depth = 0;
+ bool ignore;
for (iter = &dev->adj_list.lower,
- ldev = netdev_next_lower_dev(dev, &iter);
+ ldev = __netdev_next_lower_dev(dev, &iter, &ignore);
ldev;
- ldev = netdev_next_lower_dev(dev, &iter)) {
+ ldev = __netdev_next_lower_dev(dev, &iter, &ignore)) {
+ if (ignore)
+ continue;
if (max_depth < ldev->lower_level)
max_depth = ldev->lower_level;
}
@@ -7035,6 +7140,7 @@ static int __netdev_adjacent_dev_insert(
adj->master = master;
adj->ref_nr = 1;
adj->private = private;
+ adj->ignore = false;
dev_hold(adj_dev);
pr_debug("Insert adjacency: dev %s adj_dev %s adj->ref_nr %d; dev_hold on %s\n",
@@ -7185,17 +7291,17 @@ static int __netdev_upper_dev_link(struc
return -EBUSY;
/* To prevent loops, check if dev is not upper device to upper_dev. */
- if (netdev_has_upper_dev(upper_dev, dev))
+ if (__netdev_has_upper_dev(upper_dev, dev))
return -EBUSY;
if ((dev->lower_level + upper_dev->upper_level) > MAX_NEST_DEV)
return -EMLINK;
if (!master) {
- if (netdev_has_upper_dev(dev, upper_dev))
+ if (__netdev_has_upper_dev(dev, upper_dev))
return -EEXIST;
} else {
- master_dev = netdev_master_upper_dev_get(dev);
+ master_dev = __netdev_master_upper_dev_get(dev);
if (master_dev)
return master_dev == upper_dev ? -EEXIST : -EBUSY;
}
@@ -7218,10 +7324,11 @@ static int __netdev_upper_dev_link(struc
goto rollback;
__netdev_update_upper_level(dev, NULL);
- netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
+ __netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
__netdev_update_lower_level(upper_dev, NULL);
- netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level, NULL);
+ __netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
+ NULL);
return 0;
@@ -7307,13 +7414,94 @@ void netdev_upper_dev_unlink(struct net_
&changeupper_info.info);
__netdev_update_upper_level(dev, NULL);
- netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
+ __netdev_walk_all_lower_dev(dev, __netdev_update_upper_level, NULL);
__netdev_update_lower_level(upper_dev, NULL);
- netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level, NULL);
+ __netdev_walk_all_upper_dev(upper_dev, __netdev_update_lower_level,
+ NULL);
}
EXPORT_SYMBOL(netdev_upper_dev_unlink);
+static void __netdev_adjacent_dev_set(struct net_device *upper_dev,
+ struct net_device *lower_dev,
+ bool val)
+{
+ struct netdev_adjacent *adj;
+
+ adj = __netdev_find_adj(lower_dev, &upper_dev->adj_list.lower);
+ if (adj)
+ adj->ignore = val;
+
+ adj = __netdev_find_adj(upper_dev, &lower_dev->adj_list.upper);
+ if (adj)
+ adj->ignore = val;
+}
+
+static void netdev_adjacent_dev_disable(struct net_device *upper_dev,
+ struct net_device *lower_dev)
+{
+ __netdev_adjacent_dev_set(upper_dev, lower_dev, true);
+}
+
+static void netdev_adjacent_dev_enable(struct net_device *upper_dev,
+ struct net_device *lower_dev)
+{
+ __netdev_adjacent_dev_set(upper_dev, lower_dev, false);
+}
+
+int netdev_adjacent_change_prepare(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev,
+ struct netlink_ext_ack *extack)
+{
+ int err;
+
+ if (!new_dev)
+ return 0;
+
+ if (old_dev && new_dev != old_dev)
+ netdev_adjacent_dev_disable(dev, old_dev);
+
+ err = netdev_upper_dev_link(new_dev, dev, extack);
+ if (err) {
+ if (old_dev && new_dev != old_dev)
+ netdev_adjacent_dev_enable(dev, old_dev);
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(netdev_adjacent_change_prepare);
+
+void netdev_adjacent_change_commit(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev)
+{
+ if (!new_dev || !old_dev)
+ return;
+
+ if (new_dev == old_dev)
+ return;
+
+ netdev_adjacent_dev_enable(dev, old_dev);
+ netdev_upper_dev_unlink(old_dev, dev);
+}
+EXPORT_SYMBOL(netdev_adjacent_change_commit);
+
+void netdev_adjacent_change_abort(struct net_device *old_dev,
+ struct net_device *new_dev,
+ struct net_device *dev)
+{
+ if (!new_dev)
+ return;
+
+ if (old_dev && new_dev != old_dev)
+ netdev_adjacent_dev_enable(dev, old_dev);
+
+ netdev_upper_dev_unlink(new_dev, dev);
+}
+EXPORT_SYMBOL(netdev_adjacent_change_abort);
+
/**
* netdev_bonding_info_change - Dispatch event about slave change
* @dev: device