Subject: [PATCH] net-next: skbuff: refactor pskb_pull

From: Richard Gobert <[email-masked]>
Date: Wed, 28 Sep 2022 14:55:31 +0200

pskb_may_pull already contains all of the checks performed by
pskb_pull.
Use pskb_may_pull for validation in pskb_pull, eliminating the
duplication and making __pskb_pull obsolete.
Replace __pskb_pull with pskb_pull where applicable.

Signed-off-by: Richard Gobert <[email-masked]>
---
 include/linux/skbuff.h | 23 +++++++++--------------
 net/ipv6/ip6_offload.c |  2 +-
 net/mac80211/rx.c      |  4 ++--
 net/xfrm/espintcp.c    |  2 +-
 4 files changed, 13 insertions(+), 18 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ca8afa382bf2..615cd660dd69 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2587,20 +2587,6 @@ void *skb_pull_data(struct sk_buff *skb, size_t len);
 
 void *__pskb_pull_tail(struct sk_buff *skb, int delta);
 
-static inline void *__pskb_pull(struct sk_buff *skb, unsigned int len)
-{
-	if (len > skb_headlen(skb) &&
-	    !__pskb_pull_tail(skb, len - skb_headlen(skb)))
-		return NULL;
-	skb->len -= len;
-	return skb->data += len;
-}
-
-static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
-{
-	return unlikely(len > skb->len) ? NULL : __pskb_pull(skb, len);
-}
-
 static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
 {
 	if (likely(len <= skb_headlen(skb)))
@@ -2610,6 +2596,15 @@ static inline bool pskb_may_pull(struct sk_buff *skb, unsigned int len)
 	return __pskb_pull_tail(skb, len - skb_headlen(skb)) != NULL;
 }
 
+static inline void *pskb_pull(struct sk_buff *skb, unsigned int len)
+{
+	if (!pskb_may_pull(skb, len))
+		return NULL;
+
+	skb->len -= len;
+	return skb->data += len;
+}
+
 void skb_condense(struct sk_buff *skb);
 
 /**
diff --git a/net/ipv6/ip6_offload.c b/net/ipv6/ip6_offload.c
index d12dba2dd535..d31775b87b6a 100644
--- a/net/ipv6/ip6_offload.c
+++ b/net/ipv6/ip6_offload.c
@@ -235,7 +235,7 @@ INDIRECT_CALLABLE_SCOPE struct sk_buff *ipv6_gro_receive(struct list_head *head,
 	proto = iph->nexthdr;
 	ops = rcu_dereference(inet6_offloads[proto]);
 	if (!ops || !ops->callbacks.gro_receive) {
-		__pskb_pull(skb, skb_gro_offset(skb));
+		pskb_pull(skb, skb_gro_offset(skb));
 		skb_gro_frag0_invalidate(skb);
 		proto = ipv6_gso_pull_exthdrs(skb, proto);
 		skb_gro_pull(skb, -skb_transport_offset(skb));
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 57df21e2170a..addc8294198b 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -49,7 +49,7 @@ static struct sk_buff *ieee80211_clean_skb(struct sk_buff *skb,
 
 	if (present_fcs_len)
 		__pskb_trim(skb, skb->len - present_fcs_len);
-	__pskb_pull(skb, rtap_space);
+	pskb_pull(skb, rtap_space);
 
 	hdr = (void *)skb->data;
 	fc = hdr->frame_control;
@@ -74,7 +74,7 @@ static struct sk_buff *ieee80211_clean_skb(struct sk_buff *skb,
 
 	memmove(skb->data + IEEE80211_HT_CTL_LEN, skb->data,
 		hdrlen - IEEE80211_HT_CTL_LEN);
-	__pskb_pull(skb, IEEE80211_HT_CTL_LEN);
+	pskb_pull(skb, IEEE80211_HT_CTL_LEN);
 
 	return skb;
 }
diff --git a/net/xfrm/espintcp.c b/net/xfrm/espintcp.c
index 82d14eea1b5a..2000d67f9982 100644
--- a/net/xfrm/espintcp.c
+++ b/net/xfrm/espintcp.c
@@ -91,7 +91,7 @@ static void espintcp_rcv(struct strparser *strp, struct sk_buff *skb)
 	}
 
 	/* remove header, leave non-ESP marker/SPI */
-	if (!__pskb_pull(skb, rxm->offset + 2)) {
+	if (!pskb_pull(skb, rxm->offset + 2)) {
 		XFRM_INC_STATS(sock_net(strp->sk), LINUX_MIB_XFRMINERROR);
 		kfree_skb(skb);
 		return;
-- 
2.20.1