net: Allow netdevices to specify needed head/tailroom

This patch adds needed_headroom/needed_tailroom members to struct
net_device and updates many places that allocate sbks to use them. Not
all of them can be converted though, and I'm sure I missed some (I
mostly grepped for LL_RESERVED_SPACE)

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Johannes Berg
2008-05-12 20:48:31 -07:00
committed by David S. Miller
parent 8388e3da34
commit f5184d267c
13 changed files with 39 additions and 31 deletions

View File

@@ -246,11 +246,16 @@ struct hh_cache
*
* We could use other alignment values, but we must maintain the
* relationship HH alignment <= LL alignment.
*
* LL_ALLOCATED_SPACE also takes into account the tailroom the device
* may need.
*/
#define LL_RESERVED_SPACE(dev) \
(((dev)->hard_header_len&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
((((dev)->hard_header_len+(dev)->needed_headroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
#define LL_RESERVED_SPACE_EXTRA(dev,extra) \
((((dev)->hard_header_len+extra)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
((((dev)->hard_header_len+(dev)->needed_headroom+(extra))&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
#define LL_ALLOCATED_SPACE(dev) \
((((dev)->hard_header_len+(dev)->needed_headroom+(dev)->needed_tailroom)&~(HH_DATA_MOD - 1)) + HH_DATA_MOD)
struct header_ops {
int (*create) (struct sk_buff *skb, struct net_device *dev,
@@ -569,6 +574,13 @@ struct net_device
unsigned short type; /* interface hardware type */
unsigned short hard_header_len; /* hardware hdr length */
/* extra head- and tailroom the hardware may need, but not in all cases
* can this be guaranteed, especially tailroom. Some cases also use
* LL_MAX_HEADER instead to allocate the skb.
*/
unsigned short needed_headroom;
unsigned short needed_tailroom;
struct net_device *master; /* Pointer to master device of a group,
* which this device is member of.
*/