Commit a47f0ce0 authored by David S. Miller's avatar David S. Miller
Browse files

[XFRM]: Kill excessive refcounting of xfrm_state objects. 



The refcounting done for timers and hash table insertions
are just wasted cycles.  We can eliminate all of this
refcounting because:

1) The implicit refcount when the xfrm_state object is active
   will always be held while the object is in the hash tables.
   We never kfree() the xfrm_state until long after we've made
   sure that it has been unhashed.

2) Timers are even easier.  Once we mark that x->km.state as
   anything other than XFRM_STATE_VALID (__xfrm_state_delete
   sets it to XFRM_STATE_DEAD), any timer that fires will
   do nothing and return without rearming the timer.

   Therefore we can defer the del_timer calls until when the
   object is about to be freed up during GC.  We have to use
   del_timer_sync() and defer it to GC because we can't do
   a del_timer_sync() while holding x->lock which all callers
   of __xfrm_state_delete hold.

This makes SA changes even more light-weight.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 1c095399

net/xfrm/xfrm_state.c

+12 −41
Original line number Diff line number Diff line
@@ -266,10 +266,8 @@ void km_state_expired(struct xfrm_state *x, int hard, u32 pid); 


static void xfrm_state_gc_destroy(struct xfrm_state *x)

{

	if (del_timer(&x->timer))

		BUG();

	if (del_timer(&x->rtimer))

		BUG();

	del_timer_sync(&x->timer);

	del_timer_sync(&x->rtimer);

	kfree(x->aalg);

	kfree(x->ealg);

	kfree(x->calg);
@@ -361,9 +359,9 @@ static void xfrm_timer_handler(unsigned long data) 
	if (warn)

		km_state_expired(x, 0, 0);

resched:

	if (next != LONG_MAX &&

	    !mod_timer(&x->timer, jiffies + make_jiffies(next)))

		xfrm_state_hold(x);

	if (next != LONG_MAX)

		mod_timer(&x->timer, jiffies + make_jiffies(next));



	goto out;



expired:
@@ -378,7 +376,6 @@ expired: 


out:

	spin_unlock(&x->lock);

	xfrm_state_put(x);

}



static void xfrm_replay_timer_handler(unsigned long data);
@@ -433,19 +430,11 @@ int __xfrm_state_delete(struct xfrm_state *x) 
		x->km.state = XFRM_STATE_DEAD;

		spin_lock(&xfrm_state_lock);

		hlist_del(&x->bydst);

		__xfrm_state_put(x);

		hlist_del(&x->bysrc);

		__xfrm_state_put(x);

		if (x->id.spi) {

		if (x->id.spi)

			hlist_del(&x->byspi);

			__xfrm_state_put(x);

		}

		xfrm_state_num--;

		spin_unlock(&xfrm_state_lock);

		if (del_timer(&x->timer))

			__xfrm_state_put(x);

		if (del_timer(&x->rtimer))

			__xfrm_state_put(x);



		/* All xfrm_state objects are created by xfrm_state_alloc.

		 * The xfrm_state_alloc call gives a reference, and that
@@ -676,17 +665,13 @@ xfrm_state_find(xfrm_address_t *daddr, xfrm_address_t *saddr, 
		if (km_query(x, tmpl, pol) == 0) {

			x->km.state = XFRM_STATE_ACQ;

			hlist_add_head(&x->bydst, xfrm_state_bydst+h);

			xfrm_state_hold(x);

			h = xfrm_src_hash(saddr, family);

			hlist_add_head(&x->bysrc, xfrm_state_bysrc+h);

			xfrm_state_hold(x);

			if (x->id.spi) {

				h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto, family);

				hlist_add_head(&x->byspi, xfrm_state_byspi+h);

				xfrm_state_hold(x);

			}

			x->lft.hard_add_expires_seconds = XFRM_ACQ_EXPIRES;

			xfrm_state_hold(x);

			x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;

			add_timer(&x->timer);

		} else {
@@ -713,26 +698,20 @@ static void __xfrm_state_insert(struct xfrm_state *x) 


	h = xfrm_dst_hash(&x->id.daddr, x->props.reqid, x->props.family);

	hlist_add_head(&x->bydst, xfrm_state_bydst+h);

	xfrm_state_hold(x);



	h = xfrm_src_hash(&x->props.saddr, x->props.family);

	hlist_add_head(&x->bysrc, xfrm_state_bysrc+h);

	xfrm_state_hold(x);



	if (xfrm_id_proto_match(x->id.proto, IPSEC_PROTO_ANY)) {

		h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto,

				  x->props.family);



		hlist_add_head(&x->byspi, xfrm_state_byspi+h);

		xfrm_state_hold(x);

	}



	if (!mod_timer(&x->timer, jiffies + HZ))

		xfrm_state_hold(x);



	if (x->replay_maxage &&

	    !mod_timer(&x->rtimer, jiffies + x->replay_maxage))

		xfrm_state_hold(x);

	mod_timer(&x->timer, jiffies + HZ);

	if (x->replay_maxage)

		mod_timer(&x->rtimer, jiffies + x->replay_maxage);



	wake_up(&km_waitq);
@@ -844,10 +823,8 @@ static struct xfrm_state *__find_acq_core(unsigned short family, u8 mode, u32 re 
		xfrm_state_hold(x);

		x->timer.expires = jiffies + XFRM_ACQ_EXPIRES*HZ;

		add_timer(&x->timer);

		xfrm_state_hold(x);

		hlist_add_head(&x->bydst, xfrm_state_bydst+h);

		h = xfrm_src_hash(saddr, family);

		xfrm_state_hold(x);

		hlist_add_head(&x->bysrc, xfrm_state_bysrc+h);

		wake_up(&km_waitq);

	}
@@ -955,8 +932,7 @@ out: 
		memcpy(&x1->lft, &x->lft, sizeof(x1->lft));

		x1->km.dying = 0;



		if (!mod_timer(&x1->timer, jiffies + HZ))

			xfrm_state_hold(x1);

		mod_timer(&x1->timer, jiffies + HZ);

		if (x1->curlft.use_time)

			xfrm_state_check_expire(x1);
@@ -981,8 +957,7 @@ int xfrm_state_check_expire(struct xfrm_state *x) 
	if (x->curlft.bytes >= x->lft.hard_byte_limit ||

	    x->curlft.packets >= x->lft.hard_packet_limit) {

		x->km.state = XFRM_STATE_EXPIRED;

		if (!mod_timer(&x->timer, jiffies))

			xfrm_state_hold(x);

		mod_timer(&x->timer, jiffies);

		return -EINVAL;

	}
@@ -1177,7 +1152,6 @@ xfrm_alloc_spi(struct xfrm_state *x, u32 minspi, u32 maxspi) 
		spin_lock_bh(&xfrm_state_lock);

		h = xfrm_spi_hash(&x->id.daddr, x->id.spi, x->id.proto, x->props.family);

		hlist_add_head(&x->byspi, xfrm_state_byspi+h);

		xfrm_state_hold(x);

		spin_unlock_bh(&xfrm_state_lock);

		wake_up(&km_waitq);

	}
@@ -1264,11 +1238,9 @@ void xfrm_replay_notify(struct xfrm_state *x, int event) 
	km_state_notify(x, &c);



	if (x->replay_maxage &&

	    !mod_timer(&x->rtimer, jiffies + x->replay_maxage)) {

		xfrm_state_hold(x);

	    !mod_timer(&x->rtimer, jiffies + x->replay_maxage))

		x->xflags &= ~XFRM_TIME_DEFER;

}

}

EXPORT_SYMBOL(xfrm_replay_notify);



static void xfrm_replay_timer_handler(unsigned long data)
@@ -1285,7 +1257,6 @@ static void xfrm_replay_timer_handler(unsigned long data) 
	}



	spin_unlock(&x->lock);

	xfrm_state_put(x);

}



int xfrm_replay_check(struct xfrm_state *x, u32 seq)

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