[3/7,media] cx231xx: drop unnecessary list_empty
Commit Message
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:
(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>
---
drivers/media/usb/cx231xx/cx231xx-core.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
@@ -115,11 +115,9 @@ void cx231xx_init_extension(struct cx231xx *dev)
struct cx231xx_ops *ops = NULL;
mutex_lock(&cx231xx_devlist_mutex);
- if (!list_empty(&cx231xx_extension_devlist)) {
- list_for_each_entry(ops, &cx231xx_extension_devlist, next) {
- if (ops->init)
- ops->init(dev);
- }
+ list_for_each_entry(ops, &cx231xx_extension_devlist, next) {
+ if (ops->init)
+ ops->init(dev);
}
mutex_unlock(&cx231xx_devlist_mutex);
}
@@ -129,11 +127,9 @@ void cx231xx_close_extension(struct cx231xx *dev)
struct cx231xx_ops *ops = NULL;
mutex_lock(&cx231xx_devlist_mutex);
- if (!list_empty(&cx231xx_extension_devlist)) {
- list_for_each_entry(ops, &cx231xx_extension_devlist, next) {
- if (ops->fini)
- ops->fini(dev);
- }
+ list_for_each_entry(ops, &cx231xx_extension_devlist, next) {
+ if (ops->fini)
+ ops->fini(dev);
}
mutex_unlock(&cx231xx_devlist_mutex);
}