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Commit f5b0a874 authored by David S. Miller's avatar David S. Miller
Browse files

net: Document dst->obsolete better. 



Add a big comment explaining how the field works, and use defines
instead of magic constants for the values assigned to it.

Suggested by Joe Perches.

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f8126f1d

include/net/dst.h

+13 −1
Original line number Diff line number Diff line
@@ -65,7 +65,19 @@ struct dst_entry { 
	unsigned short		pending_confirm;



	short			error;



	/* A non-zero value of dst->obsolete forces by-hand validation

	 * of the route entry.  Positive values are set by the generic

	 * dst layer to indicate that the entry has been forcefully

	 * destroyed.

	 *

	 * Negative values are used by the implementation layer code to

	 * force invocation of the dst_ops->check() method.

	 */

	short			obsolete;

#define DST_OBSOLETE_NONE	0

#define DST_OBSOLETE_DEAD	2

#define DST_OBSOLETE_FORCE_CHK	-1

	unsigned short		header_len;	/* more space at head required */

	unsigned short		trailer_len;	/* space to reserve at tail */

#ifdef CONFIG_IP_ROUTE_CLASSID
@@ -359,7 +371,7 @@ extern struct dst_entry *dst_destroy(struct dst_entry *dst); 


static inline void dst_free(struct dst_entry *dst)

{

	if (dst->obsolete > 1)

	if (dst->obsolete > 0)

		return;

	if (!atomic_read(&dst->__refcnt)) {

		dst = dst_destroy(dst);

net/core/dst.c

+2 −2
Original line number Diff line number Diff line
@@ -94,7 +94,7 @@ loop: 
			 * But we do not have state "obsoleted, but

			 * referenced by parent", so it is right.

			 */

			if (dst->obsolete > 1)

			if (dst->obsolete > 0)

				continue;



			___dst_free(dst);
@@ -202,7 +202,7 @@ static void ___dst_free(struct dst_entry *dst) 
	 */

	if (dst->dev == NULL || !(dst->dev->flags&IFF_UP))

		dst->input = dst->output = dst_discard;

	dst->obsolete = 2;

	dst->obsolete = DST_OBSOLETE_DEAD;

}



void __dst_free(struct dst_entry *dst)

net/decnet/dn_route.c

+2 −2
Original line number Diff line number Diff line
@@ -1176,7 +1176,7 @@ make_route: 
	if (dev_out->flags & IFF_LOOPBACK)

		flags |= RTCF_LOCAL;



	rt = dst_alloc(&dn_dst_ops, dev_out, 1, 0, DST_HOST);

	rt = dst_alloc(&dn_dst_ops, dev_out, 1, DST_OBSOLETE_NONE, DST_HOST);

	if (rt == NULL)

		goto e_nobufs;
@@ -1444,7 +1444,7 @@ static int dn_route_input_slow(struct sk_buff *skb) 
	}



make_route:

	rt = dst_alloc(&dn_dst_ops, out_dev, 0, 0, DST_HOST);

	rt = dst_alloc(&dn_dst_ops, out_dev, 0, DST_OBSOLETE_NONE, DST_HOST);

	if (rt == NULL)

		goto e_nobufs;

net/ipv4/route.c

+3 −2
Original line number Diff line number Diff line
@@ -1221,7 +1221,7 @@ static void rt_set_nexthop(struct rtable *rt, const struct flowi4 *fl4, 
static struct rtable *rt_dst_alloc(struct net_device *dev,

				   bool nopolicy, bool noxfrm)

{

	return dst_alloc(&ipv4_dst_ops, dev, 1, -1,

	return dst_alloc(&ipv4_dst_ops, dev, 1, DST_OBSOLETE_FORCE_CHK,

			 DST_HOST | DST_NOCACHE |

			 (nopolicy ? DST_NOPOLICY : 0) |

			 (noxfrm ? DST_NOXFRM : 0));
@@ -1969,9 +1969,10 @@ static struct dst_ops ipv4_dst_blackhole_ops = { 


struct dst_entry *ipv4_blackhole_route(struct net *net, struct dst_entry *dst_orig)

{

	struct rtable *rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, 0, 0);

	struct rtable *ort = (struct rtable *) dst_orig;

	struct rtable *rt;



	rt = dst_alloc(&ipv4_dst_blackhole_ops, NULL, 1, DST_OBSOLETE_NONE, 0);

	if (rt) {

		struct dst_entry *new = &rt->dst;

net/ipv6/route.c

+2 −2
Original line number Diff line number Diff line
@@ -281,7 +281,7 @@ static inline struct rt6_info *ip6_dst_alloc(struct net *net, 
					     struct fib6_table *table)

{

	struct rt6_info *rt = dst_alloc(&net->ipv6.ip6_dst_ops, dev,

					0, 0, flags);

					0, DST_OBSOLETE_NONE, flags);



	if (rt) {

		struct dst_entry *dst = &rt->dst;
@@ -985,7 +985,7 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori 
	struct rt6_info *rt, *ort = (struct rt6_info *) dst_orig;

	struct dst_entry *new = NULL;



	rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, 0, 0);

	rt = dst_alloc(&ip6_dst_blackhole_ops, ort->dst.dev, 1, DST_OBSOLETE_NONE, 0);

	if (rt) {

		new = &rt->dst;