[PATCH net-next v2 15/18] net: netcp: Remove usage of list iterator for list_add() after loop body

Jakob Koschel
2022-04-12T11:12:09Z

In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer pointing to the location
where the element should be inserted [1].

Before, the code implicitly used the head when no element was found
when using &next->list. The new 'pos' variable is set to the list head
by default and overwritten if the list exits early, marking the
insertion point for list_add().

Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1]
Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com>
---
drivers/net/ethernet/ti/netcp_core.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/ti/netcp_core.c b/drivers/net/ethernet/ti/netcp_core.c
index 16507bff652a..f25104b5a31b 100644
--- a/drivers/net/ethernet/ti/netcp_core.c
+++ b/drivers/net/ethernet/ti/netcp_core.c
@@ -471,6 +471,7 @@ struct netcp_hook_list {
int netcp_register_txhook(struct netcp_intf *netcp_priv, int order,
netcp_hook_rtn *hook_rtn, void *hook_data)
{
+ struct list_head *pos = &netcp_priv->txhook_list_head;
struct netcp_hook_list *entry;
struct netcp_hook_list *next;
unsigned long flags;
@@ -485,10 +486,12 @@ int netcp_register_txhook(struct netcp_intf *netcp_priv, int order,

spin_lock_irqsave(&netcp_priv->lock, flags);
list_for_each_entry(next, &netcp_priv->txhook_list_head, list) {
- if (next->order > order)
+ if (next->order > order) {
+ pos = &next->list;
break;
+ }
}
- __list_add(&entry->list, next->list.prev, &next->list);
+ list_add_tail(&entry->list, pos);
spin_unlock_irqrestore(&netcp_priv->lock, flags);

return 0;
@@ -520,6 +523,7 @@ EXPORT_SYMBOL_GPL(netcp_unregister_txhook);
int netcp_register_rxhook(struct netcp_intf *netcp_priv, int order,
netcp_hook_rtn *hook_rtn, void *hook_data)
{
+ struct list_head *pos = &netcp_priv->rxhook_list_head;
struct netcp_hook_list *entry;
struct netcp_hook_list *next;
unsigned long flags;
@@ -534,10 +538,12 @@ int netcp_register_rxhook(struct netcp_intf *netcp_priv, int order,

spin_lock_irqsave(&netcp_priv->lock, flags);
list_for_each_entry(next, &netcp_priv->rxhook_list_head, list) {
- if (next->order > order)
+ if (next->order > order) {
+ pos = &next->list;
break;
+ }
}
- __list_add(&entry->list, next->list.prev, &next->list);
+ list_add_tail(&entry->list, pos);
spin_unlock_irqrestore(&netcp_priv->lock, flags);

return 0;