New macro list_for_each_entry_dequeue loops over a list by popping entries
from the head, allowing a more concise expression of the dequeue-enqueue
model of list processing and avoiding the need for a 'next' pointer (as
used in list_for_each_entry_safe).
Signed-off-by: Edward Cree <ec...@solarflare.com>
---
include/linux/list.h | 15 +++++++++++++++
include/linux/netfilter.h | 6 ++----
net/core/dev.c | 6 ++----
net/ipv4/ip_input.c | 10 ++++------
net/ipv6/ip6_input.c | 10 ++++------
5 files changed, 27 insertions(+), 20 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index de04cc5ed536..150751d03441 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -645,6 +645,21 @@ static inline void list_splice_tail_init(struct list_head
*list,
#define list_safe_reset_next(pos, n, member) \
n = list_next_entry(pos, member)
+/**
+ * list_for_each_entry_dequeue - iterate over list by removing entries
+ * @pos: the type * to use as a loop cursor.
+ * @head: the head for your list.
+ * @member: the name of the list_head within the struct.
+ *
+ * Iterate over list of given type, removing each entry from the list before
+ * running the loop body. The loop will run until the list is empty, so
+ * adding an entry back onto the list in the loop body will requeue it.
+ */
+#define list_for_each_entry_dequeue(pos, head, member) \
+ while (!list_empty(head) && \
+ (pos = list_first_entry(head, typeof(*pos), member)) && \
+ (list_del(&pos->member), true))
+
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 23b48de8c2e2..f9a037eb053d 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -293,15 +293,13 @@ NF_HOOK_LIST(uint8_t pf, unsigned int hook, struct net
*net, struct sock *sk,
struct list_head *head, struct net_device *in, struct net_device
*out,
int (*okfn)(struct net *, struct sock *, struct sk_buff *))
{
- struct sk_buff *skb, *next;
struct list_head sublist;
+ struct sk_buff *skb;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
- list_del(&skb->list);
+ list_for_each_entry_dequeue(skb, head, list)
if (nf_hook(pf, hook, net, sk, skb, in, out, okfn) == 1)
list_add_tail(&skb->list, &sublist);
- }
/* Put passed packets back on main list */
list_splice(&sublist, head);
}
diff --git a/net/core/dev.c b/net/core/dev.c
index ce4583564e00..68055f012d13 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4985,9 +4985,8 @@ static void netif_receive_skb_list_internal(struct
list_head *head)
struct list_head sublist;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
net_timestamp_check(netdev_tstamp_prequeue, skb);
- list_del(&skb->list);
if (!skb_defer_rx_timestamp(skb))
list_add_tail(&skb->list, &sublist);
}
@@ -4996,9 +4995,8 @@ static void netif_receive_skb_list_internal(struct
list_head *head)
if (static_branch_unlikely(&generic_xdp_needed_key)) {
preempt_disable();
rcu_read_lock();
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
xdp_prog = rcu_dereference(skb->dev->xdp_prog);
- list_del(&skb->list);
if (do_xdp_generic(xdp_prog, skb) == XDP_PASS)
list_add_tail(&skb->list, &sublist);
}
diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index 1a3b6f32b1c9..26285a24c067 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -538,14 +538,13 @@ static void ip_list_rcv_finish(struct net *net, struct
sock *sk,
struct list_head *head)
{
struct dst_entry *curr_dst = NULL;
- struct sk_buff *skb, *next;
struct list_head sublist;
+ struct sk_buff *skb;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
struct dst_entry *dst;
- list_del(&skb->list);
/* if ingress device is enslaved to an L3 master device pass the
* skb to its handler for processing
*/
@@ -584,15 +583,14 @@ void ip_list_rcv(struct list_head *head, struct
packet_type *pt,
{
struct net_device *curr_dev = NULL;
struct net *curr_net = NULL;
- struct sk_buff *skb, *next;
struct list_head sublist;
+ struct sk_buff *skb;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
struct net_device *dev = skb->dev;
struct net *net = dev_net(dev);
- list_del(&skb->list);
skb = ip_rcv_core(skb, net);
if (skb == NULL)
continue;
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 6242682be876..65344cef0edd 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -88,14 +88,13 @@ static void ip6_list_rcv_finish(struct net *net, struct
sock *sk,
struct list_head *head)
{
struct dst_entry *curr_dst = NULL;
- struct sk_buff *skb, *next;
struct list_head sublist;
+ struct sk_buff *skb;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
struct dst_entry *dst;
- list_del(&skb->list);
/* if ingress device is enslaved to an L3 master device pass the
* skb to its handler for processing
*/
@@ -287,15 +286,14 @@ void ipv6_list_rcv(struct list_head *head, struct
packet_type *pt,
{
struct net_device *curr_dev = NULL;
struct net *curr_net = NULL;
- struct sk_buff *skb, *next;
struct list_head sublist;
+ struct sk_buff *skb;
INIT_LIST_HEAD(&sublist);
- list_for_each_entry_safe(skb, next, head, list) {
+ list_for_each_entry_dequeue(skb, head, list) {
struct net_device *dev = skb->dev;
struct net *net = dev_net(dev);
- list_del(&skb->list);
skb = ip6_rcv_core(skb, dev, net);
if (skb == NULL)
continue;
