Le 07/04/2022 à 12:28, Jakob Koschel a écrit :
quoted hunk ↗ jump to hunk
In preparation to limit the scope of a list iterator to the list
traversal loop, use a dedicated pointer to point to the found element [1].
Before, the code implicitly used the head when no element was found
when using &pos->list. Since the new variable is only set if an
element was found, the list_add() is performed within the loop
and only done after the loop if it is done on the list head directly.
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ (local) [1]
Signed-off-by: Jakob Koschel <redacted>
---
drivers/net/dsa/sja1105/sja1105_vl.c | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c
index b7e95d60a6e4..cfcae4d19eef 100644
--- a/drivers/net/dsa/sja1105/sja1105_vl.c
+++ b/drivers/net/dsa/sja1105/sja1105_vl.c
@@ -27,20 +27,24 @@ static int sja1105_insert_gate_entry(struct sja1105_gating_config *gating_cfg,
if (list_empty(&gating_cfg->entries)) {
list_add(&e->list, &gating_cfg->entries);
} else {
- struct sja1105_gate_entry *p;
+ struct sja1105_gate_entry *p = NULL, *iter;
- list_for_each_entry(p, &gating_cfg->entries, list) {
- if (p->interval == e->interval) {
+ list_for_each_entry(iter, &gating_cfg->entries, list) {
+ if (iter->interval == e->interval) {
NL_SET_ERR_MSG_MOD(extack,
"Gate conflict");
rc = -EBUSY;
goto err;
}
- if (e->interval < p->interval)
+ if (e->interval < iter->interval) {
+ p = iter;
+ list_add(&e->list, iter->list.prev);
break;
+ }
}
- list_add(&e->list, p->list.prev);
+ if (!p)
+ list_add(&e->list, gating_cfg->entries.prev);
}
gating_cfg->num_entries++;
This change looks ugly, why duplicating the list_add() to do the same ?
At the end of the loop the pointer contains gating_cfg->entries, so it
was cleaner before.
If you don't want to use the loop index outside the loop, fair enough,
all you have to do is:
struct sja1105_gate_entry *p, *iter;
list_for_each_entry(iter, &gating_cfg->entries, list) {
if (iter->interval == e->interval) {
NL_SET_ERR_MSG_MOD(extack,
"Gate conflict");
rc = -EBUSY;
goto err;
}
p = iter;
if (e->interval < iter->interval)
break;
}
list_add(&e->list, p->list.prev);
Christophe