net/mlx5: drop unnecessary list_empty

list_for_each_entry is able to handle an empty list.
The only effect of avoiding the loop is not initializing the
index variable.
Drop list_empty tests in cases where these variables are not
used.

Note that list_for_each_entry is defined in terms of list_first_entry,
which indicates that it should not be used on an empty list.  But in
list_for_each_entry, the element obtained by list_first_entry is not
really accessed, only the address of its list_head field is compared
to the address of the list head, so the list_first_entry is safe.

The semantic patch that makes this change is as follows (with another
variant for the no brace case): (http://coccinelle.lip6.fr/)

<smpl>
@@
expression x,e;
iterator name list_for_each_entry;
statement S;
identifier i;
@@

-if (!(list_empty(x))) {
   list_for_each_entry(i,x,...) S
- }
 ... when != i
? i = e
</smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c
index 6960aed..c63f727 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_matcher.c
@@ -474,14 +474,13 @@ static int dr_matcher_add_to_tbl(struct mlx5dr_matcher *matcher)
        int ret;
 
        next_matcher = NULL;
-       if (!list_empty(&tbl->matcher_list))
-               list_for_each_entry(tmp_matcher, &tbl->matcher_list, matcher_list) {
-                       if (tmp_matcher->prio >= matcher->prio) {
-                               next_matcher = tmp_matcher;
-                               break;
-                       }
-                       first = false;
+       list_for_each_entry(tmp_matcher, &tbl->matcher_list, matcher_list) {
+               if (tmp_matcher->prio >= matcher->prio) {
+                       next_matcher = tmp_matcher;
+                       break;
                }
+               first = false;
+       }
 
        prev_matcher = NULL;
        if (next_matcher && !first)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
index cd708dc..6ec5106 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/steering/dr_rule.c
@@ -574,9 +574,8 @@ void mlx5dr_rule_update_rule_member(struct mlx5dr_ste *ste,
 {
        struct mlx5dr_rule_member *rule_mem;
 
-       if (!list_empty(&ste->rule_list))
-               list_for_each_entry(rule_mem, &ste->rule_list, use_ste_list)
-                       rule_mem->ste = new_ste;
+       list_for_each_entry(rule_mem, &ste->rule_list, use_ste_list)
+               rule_mem->ste = new_ste;
 }
 
 static void dr_rule_clean_rule_members(struct mlx5dr_rule *rule,