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xfrm: state: delay freeing until rcu grace period has elapsed

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The hash table backend memory and the state structs are free'd via
kfree/vfree.

Once we only rely on rcu during lookups we have to make sure no other cpu
is currently accessing this before doing the free.

Free operations already happen from worker so we can use synchronize_rcu
to wait until concurrent readers are done.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This commit is contained in:
Florian Westphal 2016-08-09 12:16:06 +02:00 committed by Steffen Klassert
parent 02efdff7e2
commit df7274eb70
1 changed files with 5 additions and 0 deletions
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5
net/xfrm/xfrm_state.c
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@ -146,6 +146,9 @@ static void xfrm_hash_resize(struct work_struct *work)
spin_unlock_bh(&net->xfrm.xfrm_state_lock);
osize = (ohashmask + 1) * sizeof(struct hlist_head);
synchronize_rcu();
xfrm_hash_free(odst, osize);
xfrm_hash_free(osrc, osize);
xfrm_hash_free(ospi, osize);
@ -369,6 +372,8 @@ static void xfrm_state_gc_task(struct work_struct *work)
hlist_move_list(&net->xfrm.state_gc_list, &gc_list);
spin_unlock_bh(&xfrm_state_gc_lock);
synchronize_rcu();
hlist_for_each_entry_safe(x, tmp, &gc_list, gclist)
xfrm_state_gc_destroy(x);
}