netdev - [PATCH 3/3] net: dst: make dst->obsolete 8-bit

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Date:   Thu,  7 Dec 2017 00:35:05 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, Alexey Dobriyan <adobriyan@...il.com>
Subject: [PATCH 3/3] net: dst: make dst->obsolete 8-bit

All values are small integers.

Space savings on x86_64:

	add/remove: 0/0 grow/shrink: 1/34 up/down: 1/-60 (-59)
	Function                                     old     new   delta
	dst_alloc                                    124     125      +1
	xfrm_negative_advice                          23      22      -1
	xfrm_dst_check                                27      26      -1
	udp_v6_early_demux                           845     844      -1
				...
	xfrm_resolve_and_create_bundle              2816    2812      -4
	dst_dev_put                                  104      99      -5
	xfrm_lookup                                 2027    2021      -6
	update_or_create_fnhe                       1339    1329     -10

Signed-off-by: Alexey Dobriyan <adobriyan@...il.com>
---
 include/net/dst.h | 8 ++++----
 net/core/dst.c    | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/include/net/dst.h b/include/net/dst.h
index 25decfa4e14a..77143ee9139c 100644
--- a/include/net/dst.h
+++ b/include/net/dst.h
@@ -55,7 +55,6 @@ struct dst_entry {
 #define DST_XFRM_TUNNEL		((dst_flags_t __force)0x20)
 #define DST_XFRM_QUEUE		((dst_flags_t __force)0x40)
 #define DST_METADATA		((dst_flags_t __force)0x80)
-	u8			__pad2;
 
 	/* A non-zero value of dst->obsolete forces by-hand validation
 	 * of the route entry.  Positive values are set by the generic
@@ -65,11 +64,12 @@ struct dst_entry {
 	 * Negative values are used by the implementation layer code to
 	 * force invocation of the dst_ops->check() method.
 	 */
-	short			obsolete;
+	s8			obsolete;
 #define DST_OBSOLETE_NONE	0
 #define DST_OBSOLETE_DEAD	2
 #define DST_OBSOLETE_FORCE_CHK	-1
 #define DST_OBSOLETE_KILL	-2
+	u16			__pad2;
 	unsigned short		header_len;	/* more space at head required */
 	unsigned short		trailer_len;	/* space to reserve at tail */
 
@@ -390,9 +390,9 @@ static inline int dst_discard(struct sk_buff *skb)
 	return dst_discard_out(&init_net, skb->sk, skb);
 }
 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
-		int initial_obsolete, dst_flags_t flags);
+		s8 initial_obsolete, dst_flags_t flags);
 void dst_init(struct dst_entry *dst, struct dst_ops *ops,
-	      struct net_device *dev, int initial_ref, int initial_obsolete,
+	      struct net_device *dev, int initial_ref, s8 initial_obsolete,
 	      dst_flags_t flags);
 struct dst_entry *dst_destroy(struct dst_entry *dst);
 void dst_dev_put(struct dst_entry *dst);
diff --git a/net/core/dst.c b/net/core/dst.c
index d7cce39c3552..dba03bf26da7 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -60,7 +60,7 @@ const struct dst_metrics dst_default_metrics = {
 };
 
 void dst_init(struct dst_entry *dst, struct dst_ops *ops,
-	      struct net_device *dev, int initial_ref, int initial_obsolete,
+	      struct net_device *dev, int initial_ref, s8 initial_obsolete,
 	      dst_flags_t flags)
 {
 	dst->dev = dev;
@@ -92,7 +92,7 @@ void dst_init(struct dst_entry *dst, struct dst_ops *ops,
 EXPORT_SYMBOL(dst_init);
 
 void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
-		int initial_ref, int initial_obsolete, dst_flags_t flags)
+		int initial_ref, s8 initial_obsolete, dst_flags_t flags)
 {
 	struct dst_entry *dst;
 
-- 
2.13.6