[PATCH net-next v2 17/18] ipvlan: Remove usage of list iterator variable for the loop body

Jakob Koschel
2022-04-12T11:14:35Z

In preparation to limit the scope of the list iterator variable to the
list traversal loop, use a dedicated pointer to iterate through the
list [1].

Since that variable should not be used past the loop iteration, a
separate variable is used to 'remember the current location within the
loop'.

To either continue iterating from that position or start a new
iteration (if the previous iteration was complete) list_prepare_entry()
is used.

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/ipvlan/ipvlan_main.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 696e245f6d00..063d7c30e944 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -9,7 +9,7 @@
static int ipvlan_set_port_mode(struct ipvl_port *port, u16 nval,
struct netlink_ext_ack *extack)
{
- struct ipvl_dev *ipvlan;
+ struct ipvl_dev *ipvlan, *tmp = NULL;
unsigned int flags;
int err;

@@ -26,8 +26,10 @@ static int ipvlan_set_port_mode(struct ipvl_port *port, u16 nval,
flags & ~IFF_NOARP,
extack);
}
- if (unlikely(err))
+ if (unlikely(err)) {
+ tmp = ipvlan;
goto fail;
+ }
}
if (nval == IPVLAN_MODE_L3S) {
/* New mode is L3S */
@@ -43,6 +45,7 @@ static int ipvlan_set_port_mode(struct ipvl_port *port, u16 nval,
return 0;

fail:
+ ipvlan = list_prepare_entry(tmp, &port->ipvlans, pnode);
/* Undo the flags changes that have been done so far. */
list_for_each_entry_continue_reverse(ipvlan, &port->ipvlans, pnode) {
flags = ipvlan->dev->flags;