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Commit 384aee46 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'neighbor-More-gc_list-changes' 



David Ahern says:

====================
neighbor: More gc_list changes

More gc_list changes and cleanups.

The first 2 patches are bug fixes from the first gc_list change.
Specifically, fix the locking order to be consistent - table lock
followed by neighbor lock, and then entries in the FAILED state
should always be candidates for forced_gc without waiting for any
time span (return to the eviction logic prior to the separate gc_list).

Patch 3 removes 2 now unnecessary arguments to neigh_del.

Patch 4 moves a helper from a header file to core code in preparation
for Patch 5 which removes NTF_EXT_LEARNED entries from the gc_list.
These entries are already exempt from forced_gc; patch 5 removes them
from consideration and makes them on par with PERMANENT entries given
that they are also managed by userspace.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents aeb3fecd e997f8a2

include/net/neighbour.h

+0 −18
Original line number Diff line number Diff line
@@ -549,24 +549,6 @@ static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n, 
	} while (read_seqretry(&n->ha_lock, seq));

}



static inline void neigh_update_ext_learned(struct neighbour *neigh, u32 flags,

					    int *notify)

{

	u8 ndm_flags = 0;



	if (!(flags & NEIGH_UPDATE_F_ADMIN))

		return;



	ndm_flags |= (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;

	if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) {

		if (ndm_flags & NTF_EXT_LEARNED)

			neigh->flags |= NTF_EXT_LEARNED;

		else

			neigh->flags &= ~NTF_EXT_LEARNED;

		*notify = 1;

	}

}



static inline void neigh_update_is_router(struct neighbour *neigh, u32 flags,

					  int *notify)

{

net/core/neighbour.c

+60 −34
Original line number Diff line number Diff line
@@ -127,40 +127,62 @@ static void neigh_mark_dead(struct neighbour *n) 
	}

}



static void neigh_change_state(struct neighbour *n, u8 new)

static void neigh_update_gc_list(struct neighbour *n)

{

	bool on_gc_list = !list_empty(&n->gc_list);

	bool new_is_perm = new & NUD_PERMANENT;

	bool on_gc_list, exempt_from_gc;



	n->nud_state = new;

	write_lock_bh(&n->tbl->lock);

	write_lock(&n->lock);



	/* remove from the gc list if new state is permanent;

	 * add to the gc list if new state is not permanent

	/* remove from the gc list if new state is permanent or if neighbor

	 * is externally learned; otherwise entry should be on the gc list

	 */

	if (new_is_perm && on_gc_list) {

		write_lock_bh(&n->tbl->lock);

		list_del_init(&n->gc_list);

		write_unlock_bh(&n->tbl->lock);

	exempt_from_gc = n->nud_state & NUD_PERMANENT ||

			 n->flags & NTF_EXT_LEARNED;

	on_gc_list = !list_empty(&n->gc_list);



	if (exempt_from_gc && on_gc_list) {

		list_del_init(&n->gc_list);

		atomic_dec(&n->tbl->gc_entries);

	} else if (!new_is_perm && !on_gc_list) {

	} else if (!exempt_from_gc && !on_gc_list) {

		/* add entries to the tail; cleaning removes from the front */

		write_lock_bh(&n->tbl->lock);

		list_add_tail(&n->gc_list, &n->tbl->gc_list);

		atomic_inc(&n->tbl->gc_entries);

	}



	write_unlock(&n->lock);

	write_unlock_bh(&n->tbl->lock);

}



		atomic_inc(&n->tbl->gc_entries);

static bool neigh_update_ext_learned(struct neighbour *neigh, u32 flags,

				     int *notify)

{

	bool rc = false;

	u8 ndm_flags;



	if (!(flags & NEIGH_UPDATE_F_ADMIN))

		return rc;



	ndm_flags = (flags & NEIGH_UPDATE_F_EXT_LEARNED) ? NTF_EXT_LEARNED : 0;

	if ((neigh->flags ^ ndm_flags) & NTF_EXT_LEARNED) {

		if (ndm_flags & NTF_EXT_LEARNED)

			neigh->flags |= NTF_EXT_LEARNED;

		else

			neigh->flags &= ~NTF_EXT_LEARNED;

		rc = true;

		*notify = 1;

	}



	return rc;

}



static bool neigh_del(struct neighbour *n, __u8 state, __u8 flags,

		      struct neighbour __rcu **np, struct neigh_table *tbl)

static bool neigh_del(struct neighbour *n, struct neighbour __rcu **np,

		      struct neigh_table *tbl)

{

	bool retval = false;



	write_lock(&n->lock);

	if (refcount_read(&n->refcnt) == 1 && !(n->nud_state & state) &&

	    !(n->flags & flags)) {

	if (refcount_read(&n->refcnt) == 1) {

		struct neighbour *neigh;



		neigh = rcu_dereference_protected(n->next,
@@ -192,7 +214,7 @@ bool neigh_remove_one(struct neighbour *ndel, struct neigh_table *tbl) 
	while ((n = rcu_dereference_protected(*np,

					      lockdep_is_held(&tbl->lock)))) {

		if (n == ndel)

			return neigh_del(n, 0, 0, np, tbl);

			return neigh_del(n, np, tbl);

		np = &n->next;

	}

	return false;
@@ -202,9 +224,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) 
{

	int max_clean = atomic_read(&tbl->gc_entries) - tbl->gc_thresh2;

	unsigned long tref = jiffies - 5 * HZ;

	u8 flags = NTF_EXT_LEARNED;

	struct neighbour *n, *tmp;

	u8 state = NUD_PERMANENT;

	int shrunk = 0;



	NEIGH_CACHE_STAT_INC(tbl, forced_gc_runs);
@@ -216,7 +236,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) 
			bool remove = false;



			write_lock(&n->lock);

			if (!(n->nud_state & state) && !(n->flags & flags) &&

			if ((n->nud_state == NUD_FAILED) ||

			    time_after(tref, n->updated))

				remove = true;

			write_unlock(&n->lock);
@@ -355,13 +375,13 @@ EXPORT_SYMBOL(neigh_ifdown); 


static struct neighbour *neigh_alloc(struct neigh_table *tbl,

				     struct net_device *dev,

				     bool permanent)

				     bool exempt_from_gc)

{

	struct neighbour *n = NULL;

	unsigned long now = jiffies;

	int entries;



	if (permanent)

	if (exempt_from_gc)

		goto do_alloc;



	entries = atomic_inc_return(&tbl->gc_entries) - 1;
@@ -403,7 +423,7 @@ static struct neighbour *neigh_alloc(struct neigh_table *tbl, 
	return n;



out_entries:

	if (!permanent)

	if (!exempt_from_gc)

		atomic_dec(&tbl->gc_entries);

	goto out;

}
@@ -550,9 +570,9 @@ EXPORT_SYMBOL(neigh_lookup_nodev); 
static struct neighbour *___neigh_create(struct neigh_table *tbl,

					 const void *pkey,

					 struct net_device *dev,

					 bool permanent, bool want_ref)

					 bool exempt_from_gc, bool want_ref)

{

	struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, permanent);

	struct neighbour *n1, *rc, *n = neigh_alloc(tbl, dev, exempt_from_gc);

	u32 hash_val;

	unsigned int key_len = tbl->key_len;

	int error;
@@ -618,7 +638,7 @@ static struct neighbour *___neigh_create(struct neigh_table *tbl, 
	}



	n->dead = 0;

	if (!permanent)

	if (!exempt_from_gc)

		list_add_tail(&n->gc_list, &n->tbl->gc_list);



	if (want_ref)
@@ -1194,6 +1214,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, 
			  u8 new, u32 flags, u32 nlmsg_pid,

			  struct netlink_ext_ack *extack)

{

	bool ext_learn_change = false;

	u8 old;

	int err;

	int notify = 0;
@@ -1214,13 +1235,13 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, 
		goto out;

	}



	neigh_update_ext_learned(neigh, flags, &notify);

	ext_learn_change = neigh_update_ext_learned(neigh, flags, &notify);



	if (!(new & NUD_VALID)) {

		neigh_del_timer(neigh);

		if (old & NUD_CONNECTED)

			neigh_suspect(neigh);

		neigh_change_state(neigh, new);

		neigh->nud_state = new;

		err = 0;

		notify = old & NUD_VALID;

		if ((old & (NUD_INCOMPLETE | NUD_PROBE)) &&
@@ -1299,7 +1320,7 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, 
						((new & NUD_REACHABLE) ?

						 neigh->parms->reachable_time :

						 0)));

		neigh_change_state(neigh, new);

		neigh->nud_state = new;

		notify = 1;

	}
@@ -1360,6 +1381,9 @@ static int __neigh_update(struct neighbour *neigh, const u8 *lladdr, 
		neigh_update_is_router(neigh, flags, &notify);

	write_unlock_bh(&neigh->lock);



	if (((new ^ old) & NUD_PERMANENT) || ext_learn_change)

		neigh_update_gc_list(neigh);



	if (notify)

		neigh_update_notify(neigh, nlmsg_pid);
@@ -1862,14 +1886,16 @@ static int neigh_add(struct sk_buff *skb, struct nlmsghdr *nlh, 


	neigh = neigh_lookup(tbl, dst, dev);

	if (neigh == NULL) {

		bool exempt_from_gc;



		if (!(nlh->nlmsg_flags & NLM_F_CREATE)) {

			err = -ENOENT;

			goto out;

		}



		neigh = ___neigh_create(tbl, dst, dev,

					ndm->ndm_state & NUD_PERMANENT,

					true);

		exempt_from_gc = ndm->ndm_state & NUD_PERMANENT ||

				 ndm->ndm_flags & NTF_EXT_LEARNED;

		neigh = ___neigh_create(tbl, dst, dev, exempt_from_gc, true);

		if (IS_ERR(neigh)) {

			err = PTR_ERR(neigh);

			goto out;