317fe0e6c5
Addition of rcu_head to struct inet_peer added 16bytes on 64bit arches. Thats a bit unfortunate, since old size was exactly 64 bytes. This can be solved, using an union between this rcu_head an four fields, that are normally used only when a refcount is taken on inet_peer. rcu_head is used only when refcnt=-1, right before structure freeing. Add a inet_peer_refcheck() function to check this assertion for a while. We can bring back SLAB_HWCACHE_ALIGN qualifier in kmem cache creation. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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* INETPEER - A storage for permanent information about peers
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*
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* Authors: Andrey V. Savochkin <saw@msu.ru>
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*/
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#ifndef _NET_INETPEER_H
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#define _NET_INETPEER_H
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#include <linux/types.h>
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#include <linux/init.h>
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#include <linux/jiffies.h>
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#include <linux/spinlock.h>
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#include <asm/atomic.h>
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struct inet_peer {
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/* group together avl_left,avl_right,v4daddr to speedup lookups */
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struct inet_peer *avl_left, *avl_right;
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__be32 v4daddr; /* peer's address */
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__u32 avl_height;
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struct list_head unused;
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__u32 dtime; /* the time of last use of not
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* referenced entries */
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atomic_t refcnt;
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/*
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* Once inet_peer is queued for deletion (refcnt == -1), following fields
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* are not available: rid, ip_id_count, tcp_ts, tcp_ts_stamp
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* We can share memory with rcu_head to keep inet_peer small
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* (less then 64 bytes)
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*/
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union {
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struct {
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atomic_t rid; /* Frag reception counter */
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atomic_t ip_id_count; /* IP ID for the next packet */
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__u32 tcp_ts;
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__u32 tcp_ts_stamp;
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};
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struct rcu_head rcu;
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};
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};
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void inet_initpeers(void) __init;
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/* can be called with or without local BH being disabled */
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struct inet_peer *inet_getpeer(__be32 daddr, int create);
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/* can be called from BH context or outside */
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extern void inet_putpeer(struct inet_peer *p);
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/*
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* temporary check to make sure we dont access rid, ip_id_count, tcp_ts,
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* tcp_ts_stamp if no refcount is taken on inet_peer
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*/
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static inline void inet_peer_refcheck(const struct inet_peer *p)
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{
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WARN_ON_ONCE(atomic_read(&p->refcnt) <= 0);
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}
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/* can be called with or without local BH being disabled */
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static inline __u16 inet_getid(struct inet_peer *p, int more)
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{
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more++;
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inet_peer_refcheck(p);
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return atomic_add_return(more, &p->ip_id_count) - more;
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}
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#endif /* _NET_INETPEER_H */
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