[PATCH v2 net-next 0/2] net: use net->dev_by_index in two places

[PATCH v2 net-next 0/2] net: use net->dev_by_index in two places

[Eric Dumazet]

Bring "ip link" ordering to /proc/net/dev one (by ifindexes).

Do the same for /proc/net/vlan/config

v2: added suggestions from Jakub Kicinski and Ido Schimmel, thanks !
  Link: https://lore.kernel.org/all/20240209142441.6c56435b@kernel.org/
  Link: https://lore.kernel.org/all/ZckR-XOsULLI9EHc@shredder/

Eric Dumazet (2):
  vlan: use xarray iterator to implement /proc/net/vlan/config
  rtnetlink: use xarray iterator to implement rtnl_dump_ifinfo()

 net/8021q/vlanproc.c | 46 ++++++++++++-----------------------
 net/core/rtnetlink.c | 58 +++++++++++++++-----------------------------
 2 files changed, 36 insertions(+), 68 deletions(-)

-- 
2.43.0.687.g38aa6559b0-goog

[PATCH v2 net-next 1/2] vlan: use xarray iterator to implement /proc/net/vlan/config

[Eric Dumazet]

Adopt net->dev_by_index as I did in commit 0e0939c0adf9
("net-procfs: use xarray iterator to implement /proc/net/dev")

Not only this removes quadratic behavior, it also makes sure
an existing vlan device is always visible in the dump,
regardless of concurrent net->dev_base_head changes.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
---
 net/8021q/vlanproc.c | 46 +++++++++++++++-----------------------------
 1 file changed, 16 insertions(+), 30 deletions(-)

diff --git a/net/8021q/vlanproc.c b/net/8021q/vlanproc.c
index 7825c129742a0f334bd8404bc3dc26547eb69083..87b959da00cd3844de1b56b45045e88e6a0293ba 100644
--- a/net/8021q/vlanproc.c
+++ b/net/8021q/vlanproc.c
@@ -163,48 +163,34 @@ void vlan_proc_rem_dev(struct net_device *vlandev)
  * The following few functions build the content of /proc/net/vlan/config
  */
 
-/* start read of /proc/net/vlan/config */
-static void *vlan_seq_start(struct seq_file *seq, loff_t *pos)
-	__acquires(rcu)
+static void *vlan_seq_from_index(struct seq_file *seq, loff_t *pos)
 {
+	unsigned long ifindex = *pos;
 	struct net_device *dev;
-	struct net *net = seq_file_net(seq);
-	loff_t i = 1;
-
-	rcu_read_lock();
-	if (*pos == 0)
-		return SEQ_START_TOKEN;
 
-	for_each_netdev_rcu(net, dev) {
+	for_each_netdev_dump(seq_file_net(seq), dev, ifindex) {
 		if (!is_vlan_dev(dev))
 			continue;
-
-		if (i++ == *pos)
-			return dev;
+		*pos = dev->ifindex;
+		return dev;
 	}
+	return NULL;
+}
+
+static void *vlan_seq_start(struct seq_file *seq, loff_t *pos)
+	__acquires(rcu)
+{
+	rcu_read_lock();
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
 
-	return  NULL;
+	return vlan_seq_from_index(seq, pos);
 }
 
 static void *vlan_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 {
-	struct net_device *dev;
-	struct net *net = seq_file_net(seq);
-
 	++*pos;
-
-	dev = v;
-	if (v == SEQ_START_TOKEN)
-		dev = net_device_entry(&net->dev_base_head);
-
-	for_each_netdev_continue_rcu(net, dev) {
-		if (!is_vlan_dev(dev))
-			continue;
-
-		return dev;
-	}
-
-	return NULL;
+	return vlan_seq_from_index(seq, pos);
 }
 
 static void vlan_seq_stop(struct seq_file *seq, void *v)
-- 
2.43.0.687.g38aa6559b0-goog

[PATCH v2 net-next 2/2] rtnetlink: use xarray iterator to implement rtnl_dump_ifinfo()

[Eric Dumazet]

Adopt net->dev_by_index as I did in commit 0e0939c0adf9
("net-procfs: use xarray iterator to implement /proc/net/dev")

This makes sure an existing device is always visible in the dump,
regardless of concurrent insertions/deletions.

v2: added suggestions from Jakub Kicinski and Ido Schimmel,
    thanks for the help !

Link: https://lore.kernel.org/all/20240209142441.6c56435b@kernel.org/
Link: https://lore.kernel.org/all/ZckR-XOsULLI9EHc@shredder/
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/core/rtnetlink.c | 58 +++++++++++++++-----------------------------
 1 file changed, 20 insertions(+), 38 deletions(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 31f433950c8dc953bcb65cc0469f7df962314b87..6f1c5537e8421bdb677e926e7fc9be1beb5ff969 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2188,25 +2188,22 @@ static int rtnl_valid_dump_ifinfo_req(const struct nlmsghdr *nlh,
 
 static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 {
+	const struct rtnl_link_ops *kind_ops = NULL;
 	struct netlink_ext_ack *extack = cb->extack;
 	const struct nlmsghdr *nlh = cb->nlh;
 	struct net *net = sock_net(skb->sk);
-	struct net *tgt_net = net;
-	int h, s_h;
-	int idx = 0, s_idx;
-	struct net_device *dev;
-	struct hlist_head *head;
+	unsigned int flags = NLM_F_MULTI;
 	struct nlattr *tb[IFLA_MAX+1];
+	struct {
+		unsigned long ifindex;
+	} *ctx = (void *)cb->ctx;
+	struct net *tgt_net = net;
 	u32 ext_filter_mask = 0;
-	const struct rtnl_link_ops *kind_ops = NULL;
-	unsigned int flags = NLM_F_MULTI;
+	struct net_device *dev;
 	int master_idx = 0;
 	int netnsid = -1;
 	int err, i;
 
-	s_h = cb->args[0];
-	s_idx = cb->args[1];
-
 	err = rtnl_valid_dump_ifinfo_req(nlh, cb->strict_check, tb, extack);
 	if (err < 0) {
 		if (cb->strict_check)
@@ -2250,36 +2247,21 @@ static int rtnl_dump_ifinfo(struct sk_buff *skb, struct netlink_callback *cb)
 		flags |= NLM_F_DUMP_FILTERED;
 
 walk_entries:
-	for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) {
-		idx = 0;
-		head = &tgt_net->dev_index_head[h];
-		hlist_for_each_entry(dev, head, index_hlist) {
-			if (link_dump_filtered(dev, master_idx, kind_ops))
-				goto cont;
-			if (idx < s_idx)
-				goto cont;
-			err = rtnl_fill_ifinfo(skb, dev, net,
-					       RTM_NEWLINK,
-					       NETLINK_CB(cb->skb).portid,
-					       nlh->nlmsg_seq, 0, flags,
-					       ext_filter_mask, 0, NULL, 0,
-					       netnsid, GFP_KERNEL);
-
-			if (err < 0) {
-				if (likely(skb->len))
-					goto out;
-
-				goto out_err;
-			}
-cont:
-			idx++;
+	err = 0;
+	for_each_netdev_dump(tgt_net, dev, ctx->ifindex) {
+		if (link_dump_filtered(dev, master_idx, kind_ops))
+			continue;
+		err = rtnl_fill_ifinfo(skb, dev, net, RTM_NEWLINK,
+				       NETLINK_CB(cb->skb).portid,
+				       nlh->nlmsg_seq, 0, flags,
+				       ext_filter_mask, 0, NULL, 0,
+				       netnsid, GFP_KERNEL);
+		if (err < 0) {
+			if (likely(skb->len))
+				err = skb->len;
+			break;
 		}
 	}
-out:
-	err = skb->len;
-out_err:
-	cb->args[1] = idx;
-	cb->args[0] = h;
 	cb->seq = tgt_net->dev_base_seq;
 	nl_dump_check_consistent(cb, nlmsg_hdr(skb));
 	if (netnsid >= 0)
-- 
2.43.0.687.g38aa6559b0-goog

Re: [PATCH v2 net-next 1/2] vlan: use xarray iterator to implement /proc/net/vlan/config

[Ido Schimmel]

On Sun, Feb 11, 2024 at 09:44:03PM +0000, Eric Dumazet wrote:
> Adopt net->dev_by_index as I did in commit 0e0939c0adf9
> ("net-procfs: use xarray iterator to implement /proc/net/dev")
> 
> Not only this removes quadratic behavior, it also makes sure
> an existing vlan device is always visible in the dump,
> regardless of concurrent net->dev_base_head changes.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reviewed-by: Jakub Kicinski <kuba@kernel.org>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Re: [PATCH v2 net-next 2/2] rtnetlink: use xarray iterator to implement rtnl_dump_ifinfo()

[Ido Schimmel]

On Sun, Feb 11, 2024 at 09:44:04PM +0000, Eric Dumazet wrote:
> Adopt net->dev_by_index as I did in commit 0e0939c0adf9
> ("net-procfs: use xarray iterator to implement /proc/net/dev")
> 
> This makes sure an existing device is always visible in the dump,
> regardless of concurrent insertions/deletions.
> 
> v2: added suggestions from Jakub Kicinski and Ido Schimmel,
>     thanks for the help !
> 
> Link: https://lore.kernel.org/all/20240209142441.6c56435b@kernel.org/
> Link: https://lore.kernel.org/all/ZckR-XOsULLI9EHc@shredder/
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Ido Schimmel <idosch@nvidia.com>

Re: [PATCH v2 net-next 0/2] net: use net->dev_by_index in two places

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sun, 11 Feb 2024 21:44:02 +0000 you wrote:
> Bring "ip link" ordering to /proc/net/dev one (by ifindexes).
> 
> Do the same for /proc/net/vlan/config
> 
> v2: added suggestions from Jakub Kicinski and Ido Schimmel, thanks !
>   Link: https://lore.kernel.org/all/20240209142441.6c56435b@kernel.org/
>   Link: https://lore.kernel.org/all/ZckR-XOsULLI9EHc@shredder/
> 
> [...]

Here is the summary with links:
  - [v2,net-next,1/2] vlan: use xarray iterator to implement /proc/net/vlan/config
    https://git.kernel.org/netdev/net-next/c/f383ced24d6a
  - [v2,net-next,2/2] rtnetlink: use xarray iterator to implement rtnl_dump_ifinfo()
    https://git.kernel.org/netdev/net-next/c/3e41af90767d

You are awesome, thank you!
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