drivers/net/ppp/ppp_generic.c | 109 ++++++++++++++++++++-------------- 1 file changed, 65 insertions(+), 44 deletions(-)
Currently, the code loads the protocol number from a skb and converts it
to host-endian for comparison. This requires runtime byte swapping on
little-endian architectures.
Optimize this by comparing the protocol number directly to
constant-folded big-endian values. This reduces code size, and slightly
improves performance in the fastpath. ppp_ioctl() still takes a
host-endian int, so keep the old function for it.
bloat-o-meter analysis on a x86_64 build:
add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-131 (-131)
Function old new delta
ppp_receive_nonmp_frame 2002 2000 -2
ppp_input 641 639 -2
npindex_to_proto 24 12 -12
npindex_to_ethertype 24 12 -12
ppp_start_xmit 375 344 -31
__ppp_xmit_process 1881 1809 -72
Total: Before=22998, After=22867, chg -0.57%
Signed-off-by: Qingfang Deng <dqfext@gmail.com>
---
drivers/net/ppp/ppp_generic.c | 109 ++++++++++++++++++++--------------
1 file changed, 65 insertions(+), 44 deletions(-)
diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index f8814d7be6f1..eca9cd6f3a87 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -239,7 +239,7 @@ struct ppp_net {
};
/* Get the PPP protocol number from a skb */
-#define PPP_PROTO(skb) get_unaligned_be16((skb)->data)
+#define PPP_PROTO(skb) get_unaligned((__be16 *)(skb)->data)
/* We limit the length of ppp->file.rq to this (arbitrary) value */
#define PPP_MAX_RQLEN 32
@@ -312,7 +312,26 @@ static inline struct ppp_net *ppp_pernet(struct net *net)
}
/* Translates a PPP protocol number to a NP index (NP == network protocol) */
-static inline int proto_to_npindex(int proto)
+static __always_inline int proto_to_npindex(__be16 proto)
+{
+ switch (proto) {
+ case htons(PPP_IP):
+ return NP_IP;
+ case htons(PPP_IPV6):
+ return NP_IPV6;
+ case htons(PPP_IPX):
+ return NP_IPX;
+ case htons(PPP_AT):
+ return NP_AT;
+ case htons(PPP_MPLS_UC):
+ return NP_MPLS_UC;
+ case htons(PPP_MPLS_MC):
+ return NP_MPLS_MC;
+ }
+ return -EINVAL;
+}
+
+static __always_inline int proto_to_npindex_user(int proto)
{
switch (proto) {
case PPP_IP:
@@ -332,44 +351,44 @@ static inline int proto_to_npindex(int proto)
}
/* Translates an NP index into a PPP protocol number */
-static const int npindex_to_proto[NUM_NP] = {
- PPP_IP,
- PPP_IPV6,
- PPP_IPX,
- PPP_AT,
- PPP_MPLS_UC,
- PPP_MPLS_MC,
+static const __be16 npindex_to_proto[NUM_NP] = {
+ htons(PPP_IP),
+ htons(PPP_IPV6),
+ htons(PPP_IPX),
+ htons(PPP_AT),
+ htons(PPP_MPLS_UC),
+ htons(PPP_MPLS_MC),
};
/* Translates an ethertype into an NP index */
-static inline int ethertype_to_npindex(int ethertype)
+static inline int ethertype_to_npindex(__be16 ethertype)
{
switch (ethertype) {
- case ETH_P_IP:
+ case htons(ETH_P_IP):
return NP_IP;
- case ETH_P_IPV6:
+ case htons(ETH_P_IPV6):
return NP_IPV6;
- case ETH_P_IPX:
+ case htons(ETH_P_IPX):
return NP_IPX;
- case ETH_P_PPPTALK:
- case ETH_P_ATALK:
+ case htons(ETH_P_PPPTALK):
+ case htons(ETH_P_ATALK):
return NP_AT;
- case ETH_P_MPLS_UC:
+ case htons(ETH_P_MPLS_UC):
return NP_MPLS_UC;
- case ETH_P_MPLS_MC:
+ case htons(ETH_P_MPLS_MC):
return NP_MPLS_MC;
}
return -1;
}
/* Translates an NP index into an ethertype */
-static const int npindex_to_ethertype[NUM_NP] = {
- ETH_P_IP,
- ETH_P_IPV6,
- ETH_P_IPX,
- ETH_P_PPPTALK,
- ETH_P_MPLS_UC,
- ETH_P_MPLS_MC,
+static const __be16 npindex_to_ethertype[NUM_NP] = {
+ htons(ETH_P_IP),
+ htons(ETH_P_IPV6),
+ htons(ETH_P_IPX),
+ htons(ETH_P_PPPTALK),
+ htons(ETH_P_MPLS_UC),
+ htons(ETH_P_MPLS_MC),
};
/*
@@ -504,7 +523,7 @@ static bool ppp_check_packet(struct sk_buff *skb, size_t count)
/* LCP packets must include LCP header which 4 bytes long:
* 1-byte code, 1-byte identifier, and 2-byte length.
*/
- return get_unaligned_be16(skb->data) != PPP_LCP ||
+ return PPP_PROTO(skb) != htons(PPP_LCP) ||
count >= PPP_PROTO_LEN + PPP_LCP_HDRLEN;
}
@@ -914,7 +933,7 @@ static long ppp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case PPPIOCSNPMODE:
if (copy_from_user(&npi, argp, sizeof(npi)))
break;
- err = proto_to_npindex(npi.protocol);
+ err = proto_to_npindex_user(npi.protocol);
if (err < 0)
break;
i = err;
@@ -1451,10 +1470,10 @@ static netdev_tx_t
ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct ppp *ppp = netdev_priv(dev);
- int npi, proto;
- unsigned char *pp;
+ __be16 *pp, proto;
+ int npi;
- npi = ethertype_to_npindex(ntohs(skb->protocol));
+ npi = ethertype_to_npindex(skb->protocol);
if (npi < 0)
goto outf;
@@ -1478,7 +1497,7 @@ ppp_start_xmit(struct sk_buff *skb, struct net_device *dev)
pp = skb_push(skb, 2);
proto = npindex_to_proto[npi];
- put_unaligned_be16(proto, pp);
+ put_unaligned(proto, pp);
skb_scrub_packet(skb, !net_eq(ppp->ppp_net, dev_net(dev)));
ppp_xmit_process(ppp, skb);
@@ -1764,14 +1783,14 @@ pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
static void
ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
{
- int proto = PPP_PROTO(skb);
+ __be16 proto = PPP_PROTO(skb);
struct sk_buff *new_skb;
int len;
unsigned char *cp;
skb->dev = ppp->dev;
- if (proto < 0x8000) {
+ if (!(proto & htons(0x8000))) {
#ifdef CONFIG_PPP_FILTER
/* check if the packet passes the pass and active filters.
* See comment for PPP_FILTER_OUTBOUND_TAG above.
@@ -2324,7 +2343,7 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
{
struct channel *pch = chan->ppp;
struct ppp *ppp;
- int proto;
+ __be16 proto;
if (!pch) {
kfree_skb(skb);
@@ -2347,7 +2366,8 @@ ppp_input(struct ppp_channel *chan, struct sk_buff *skb)
}
proto = PPP_PROTO(skb);
- if (!ppp || proto >= 0xc000 || proto == PPP_CCPFRAG) {
+ if (!ppp || (proto & htons(0xc000)) == htons(0xc000) ||
+ proto == htons(PPP_CCPFRAG)) {
/* put it on the channel queue */
skb_queue_tail(&pch->file.rq, skb);
/* drop old frames if queue too long */
@@ -2399,7 +2419,7 @@ ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb, struct channel *pch)
skb_checksum_complete_unset(skb);
#ifdef CONFIG_PPP_MULTILINK
/* XXX do channel-level decompression here */
- if (PPP_PROTO(skb) == PPP_MP)
+ if (PPP_PROTO(skb) == htons(PPP_MP))
ppp_receive_mp_frame(ppp, skb, pch);
else
#endif /* CONFIG_PPP_MULTILINK */
@@ -2422,7 +2442,8 @@ static void
ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
{
struct sk_buff *ns;
- int proto, len, npi;
+ int len, npi;
+ __be16 proto;
/*
* Decompress the frame, if compressed.
@@ -2441,7 +2462,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
*/
proto = PPP_PROTO(skb);
switch (proto) {
- case PPP_VJC_COMP:
+ case htons(PPP_VJC_COMP):
/* decompress VJ compressed packets */
if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
goto err;
@@ -2473,10 +2494,10 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
skb_put(skb, len - skb->len);
else if (len < skb->len)
skb_trim(skb, len);
- proto = PPP_IP;
+ proto = htons(PPP_IP);
break;
- case PPP_VJC_UNCOMP:
+ case htons(PPP_VJC_UNCOMP):
if (!ppp->vj || (ppp->flags & SC_REJ_COMP_TCP))
goto err;
@@ -2490,10 +2511,10 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
netdev_err(ppp->dev, "PPP: VJ uncompressed error\n");
goto err;
}
- proto = PPP_IP;
+ proto = htons(PPP_IP);
break;
- case PPP_CCP:
+ case htons(PPP_CCP):
ppp_ccp_peek(ppp, skb, 1);
break;
}
@@ -2546,7 +2567,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
/* chop off protocol */
skb_pull_rcsum(skb, 2);
skb->dev = ppp->dev;
- skb->protocol = htons(npindex_to_ethertype[npi]);
+ skb->protocol = npindex_to_ethertype[npi];
skb_reset_mac_header(skb);
skb_scrub_packet(skb, !net_eq(ppp->ppp_net,
dev_net(ppp->dev)));
@@ -2563,7 +2584,7 @@ ppp_receive_nonmp_frame(struct ppp *ppp, struct sk_buff *skb)
static struct sk_buff *
ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
{
- int proto = PPP_PROTO(skb);
+ __be16 proto = PPP_PROTO(skb);
struct sk_buff *ns;
int len;
@@ -2573,7 +2594,7 @@ ppp_decompress_frame(struct ppp *ppp, struct sk_buff *skb)
if (!pskb_may_pull(skb, skb->len))
goto err;
- if (proto == PPP_COMP) {
+ if (proto == htons(PPP_COMP)) {
int obuff_size;
switch(ppp->rcomp->compress_proto) {
--
2.43.0© 2016 - 2026 Red Hat, Inc.