| Message ID | 20221115211515.3750209-5-u.kleine-koenig@pengutronix.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | pwm: Some refactoring of pwmchip_add() | expand |
On Tue, Nov 15, 2022 at 10:15:15PM +0100, Uwe Kleine-König wrote: > list_add() just overwrites the members of the element to add (here: > chip->list) without any checks, even in the DEBUG_LIST case. So save the > effort to initialize the list. This is good patch. I agree with it. The cause of this code appearing either some older changes, or cargo cult of the trick similar to when list_del_init() is used against a list node. (FYI: that trick is useful to simplify the check if the node in question belongs to any list, by calling list_empty() against _node_ pointer) The _add_ case with initialization makes no sense to me, Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> > Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> > --- > Hello, > > this patch I'm not sure about. A quick grep shows there are (only?) 40 > more code locations that call INIT_LIST_HEAD just before list_add(). > In my understanding INIT_LIST_HEAD is only to initialize lists, but > chip->list is not a list, but the data needed to track chip as a list > member. > > Best regards > Uwe > > drivers/pwm/core.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c > index b43b24bd3c9f..61bacd8d9b44 100644 > --- a/drivers/pwm/core.c > +++ b/drivers/pwm/core.c > @@ -299,7 +299,6 @@ int pwmchip_add(struct pwm_chip *chip) > radix_tree_insert(&pwm_tree, pwm->pwm, pwm); > } > > - INIT_LIST_HEAD(&chip->list); > list_add(&chip->list, &pwm_chips); > > mutex_unlock(&pwm_lock); > -- > 2.38.1 >
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index b43b24bd3c9f..61bacd8d9b44 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -299,7 +299,6 @@ int pwmchip_add(struct pwm_chip *chip) radix_tree_insert(&pwm_tree, pwm->pwm, pwm); } - INIT_LIST_HEAD(&chip->list); list_add(&chip->list, &pwm_chips); mutex_unlock(&pwm_lock);
list_add() just overwrites the members of the element to add (here: chip->list) without any checks, even in the DEBUG_LIST case. So save the effort to initialize the list. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- Hello, this patch I'm not sure about. A quick grep shows there are (only?) 40 more code locations that call INIT_LIST_HEAD just before list_add(). In my understanding INIT_LIST_HEAD is only to initialize lists, but chip->list is not a list, but the data needed to track chip as a list member. Best regards Uwe drivers/pwm/core.c | 1 - 1 file changed, 1 deletion(-)