Commit 0e0939c0 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
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net-procfs: use xarray iterator to implement /proc/net/dev 



In commit 759ab1ed ("net: store netdevs in an xarray")
Jakub added net->dev_by_index to map ifindex to netdevices.

We can get rid of the old hash table (net->dev_index_head),
one patch at a time, if performance is acceptable.

This patch removes unpleasant code to something more readable.

As a bonus, /proc/net/dev gets netdevices sorted by their ifindex.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240207165318.3814525-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 6fb5dfee

net/core/net-procfs.c

+7 −41
Original line number Diff line number Diff line
@@ -6,49 +6,18 @@ 


#include "dev.h"



#define BUCKET_SPACE (32 - NETDEV_HASHBITS - 1)



#define get_bucket(x) ((x) >> BUCKET_SPACE)

#define get_offset(x) ((x) & ((1 << BUCKET_SPACE) - 1))

#define set_bucket_offset(b, o) ((b) << BUCKET_SPACE | (o))



static inline struct net_device *dev_from_same_bucket(struct seq_file *seq, loff_t *pos)

static void *dev_seq_from_index(struct seq_file *seq, loff_t *pos)

{

	struct net *net = seq_file_net(seq);

	unsigned long ifindex = *pos;

	struct net_device *dev;

	struct hlist_head *h;

	unsigned int count = 0, offset = get_offset(*pos);



	h = &net->dev_index_head[get_bucket(*pos)];

	hlist_for_each_entry_rcu(dev, h, index_hlist) {

		if (++count == offset)

	for_each_netdev_dump(seq_file_net(seq), dev, ifindex) {

		*pos = dev->ifindex;

		return dev;

	}



	return NULL;

}



static inline struct net_device *dev_from_bucket(struct seq_file *seq, loff_t *pos)

{

	struct net_device *dev;

	unsigned int bucket;



	do {

		dev = dev_from_same_bucket(seq, pos);

		if (dev)

			return dev;



		bucket = get_bucket(*pos) + 1;

		*pos = set_bucket_offset(bucket, 1);

	} while (bucket < NETDEV_HASHENTRIES);



	return NULL;

}



/*

 *	This is invoked by the /proc filesystem handler to display a device

 *	in detail.

 */

static void *dev_seq_start(struct seq_file *seq, loff_t *pos)

	__acquires(RCU)

{
@@ -56,16 +25,13 @@ static void *dev_seq_start(struct seq_file *seq, loff_t *pos) 
	if (!*pos)

		return SEQ_START_TOKEN;



	if (get_bucket(*pos) >= NETDEV_HASHENTRIES)

		return NULL;



	return dev_from_bucket(seq, pos);

	return dev_seq_from_index(seq, pos);

}



static void *dev_seq_next(struct seq_file *seq, void *v, loff_t *pos)

{

	++*pos;

	return dev_from_bucket(seq, pos);

	return dev_seq_from_index(seq, pos);

}



static void dev_seq_stop(struct seq_file *seq, void *v)