Hello Ben,
Yes, a *_safe
list traversal method can meet the needs,
I will modify it and simplify the codes.
Thanks,
Tang Junhui
发件人:
"Benjamin
Marzinski" <bmarzins@redhat.com>
收件人:
tang.junhui@zte.com.cn,
抄送:
tang.wenjun3@zte.com.cn,
zhang.kai16@zte.com.cn, dm-devel@redhat.com, bart.vanassche@sandisk.com,
mwilck@suse.com
日期:
2017/01/04
08:39
主题:
Re: [dm-devel]
[PATCH 09/12] multipathd: merge uevents before proccessing
发件人:
dm-devel-bounces@redhat.com
On Tue, Dec 27, 2016 at 04:03:26PM +0800, tang.junhui@zte.com.cn
wrote:
> From: tang.junhui <tang.junhui@zte.com.cn>
>
> These uevents are going to be merged:
> 1) uevents come from paths and
> 2) uevents type is same and
> 3) uevents type is addition or deletion and
> 4) uevents wwid is same.
This is just a nit, and I might be missing something subtle here, but it
seems like instead of adding list_for_some_entry_reverse, and then
breaking the abstraction to manually get previous entries, you could
have just added list_for_some_entry_reverse_safe in your earlier patch,
and hid the work of traversing a list while removing elements behind the
well understood abstraction of a *_safe list traversal method.
-Ben
>
> Change-Id: I05ee057391c092aa0c5f989b7a4f9cb550bb4d98
> Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
> ---
> libmultipath/uevent.c | 125 +++++++++++++++++++++++++++++++++++++++++++++-----
> 1 file changed, 114 insertions(+), 11 deletions(-)
>
> diff --git a/libmultipath/uevent.c b/libmultipath/uevent.c
> index b0b05e9..114068c 100644
> --- a/libmultipath/uevent.c
> +++ b/libmultipath/uevent.c
> @@ -85,6 +85,20 @@ struct uevent * alloc_uevent (void)
>
return uev;
> }
>
> +void
> +uevq_cleanup(struct list_head *tmpq)
> +{
> +
struct uevent *uev, *tmp;
> +
> +
list_for_each_entry_safe(uev, tmp, tmpq, node) {
> +
list_del_init(&uev->node);
> +
> +
if
(uev->udev)
> +
udev_device_unref(uev->udev);
> +
FREE(uev);
> +
}
> +}
> +
> bool
> uevent_can_discard(char *devpath, char *kernel)
> {
> @@ -125,6 +139,103 @@ uevent_can_discard(char *devpath, char *kernel)
>
return false;
> }
>
> +bool
> +merge_need_stop(struct uevent *earlier, struct uevent *later)
> +{
> +
/*
> +
* dm uevent do not try to merge with left uevents
> +
*/
> +
if (!strncmp(later->kernel, "dm-", 3))
> +
return
true;
> +
> +
/*
> +
* we can not make a jugement without wwid,
> +
* so it is sensible to stop merging
> +
*/
> +
if (!earlier->wwid || !later->wwid)
> +
return
true;
> +
/*
> +
* uevents merging stoped
> +
* when we meet an opposite action uevent from the same LUN to AVOID
> +
* "add path1 |remove path1 |add path2 |remove path2 |add path3"
> +
* to merge as "remove path1, path2" and "add path1,
path2, path3"
> +
* OR
> +
* "remove path1 |add path1 |remove path2 |add path2 |remove
path3"
> +
* to merge as "add path1, path2" and "remove path1,
path2, path3"
> +
* SO
> +
* when we meet a non-change uevent from the same LUN
> +
* with the same wwid and different action
> +
* it would be better to stop merging.
> +
*/
> +
if (!strcmp(earlier->wwid, later->wwid) &&
> +
strcmp(earlier->action, later->action) &&
> +
strcmp(earlier->action, "change") &&
> +
strcmp(later->action, "change"))
> +
return
true;
> +
> +
return false;
> +}
> +
> +bool
> +uevent_can_merge(struct uevent *earlier, struct uevent *later)
> +{
> +
/* merge paths uevents
> +
* whose wwids exsit and are same
> +
* and actions are same,
> +
* and actions are addition or deletion
> +
*/
> +
if (earlier->wwid && later->wwid &&
> +
!strcmp(earlier->wwid, later->wwid) &&
> +
!strcmp(earlier->action, later->action) &&
> +
strncmp(earlier->action, "change", 6) &&
> +
strncmp(earlier->kernel, "dm-", 3)) {
> +
return
true;
> +
}
> +
> +
return false;
> +}
> +
> +void
> +uevent_merge(struct uevent *later, struct list_head *tmpq)
> +{
> +
struct uevent *earlier, *temp;
> +
/*
> +
* compare the uevent with earlier uevents
> +
*/
> +
list_for_some_entry_reverse(earlier, &later->node, tmpq, node) {
> +next_earlier_node:
> +
if
(merge_need_stop(earlier, later))
> +
break;
> +
/*
> +
* try to merge earlier uevents to the later uevent
> +
*/
> +
if
(uevent_can_merge(earlier, later)) {
> +
condlog(3, "merged uevent: %s-%s-%s with uevent: %s-%s-%s",
> +
earlier->action,
earlier->kernel, earlier->wwid,
> +
later->action,
later->kernel, later->wwid);
> +
temp = earlier;
> +
> +
earlier = list_entry(earlier->node.prev, typeof(struct uevent), node);
> +
list_move(&temp->node, &later->merge_node);
> +
> +
if (earlier == list_entry(tmpq, typeof(struct uevent), node))
> +
break;
> +
else
> +
goto
next_earlier_node;
> +
}
> +
}
> +}
> +
> +void
> +merge_uevq(struct list_head *tmpq)
> +{
> +
struct uevent *later;
> +
> +
list_for_each_entry_reverse(later, tmpq, node) {
> +
uevent_merge(later,
tmpq);
> +
}
> +}
> +
> void
> service_uevq(struct list_head *tmpq)
> {
> @@ -136,6 +247,8 @@ service_uevq(struct list_head *tmpq)
>
if
(my_uev_trigger && my_uev_trigger(uev, my_trigger_data))
>
condlog(0, "uevent trigger error");
>
> +
uevq_cleanup(&uev->merge_node);
> +
>
if
(uev->udev)
>
udev_device_unref(uev->udev);
>
FREE(uev);
> @@ -150,17 +263,6 @@ static void uevent_cleanup(void *arg)
>
udev_unref(udev);
> }
>
> -void
> -uevq_cleanup(struct list_head *tmpq)
> -{
> -
struct uevent *uev, *tmp;
> -
> -
list_for_each_entry_safe(uev, tmp, tmpq, node) {
> -
list_del_init(&uev->node);
> -
FREE(uev);
> -
}
> -}
> -
> /*
> * Service the uevent queue.
> */
> @@ -189,6 +291,7 @@ int uevent_dispatch(int (*uev_trigger)(struct
uevent *, void * trigger_data),
>
pthread_mutex_unlock(uevq_lockp);
>
if
(!my_uev_trigger)
>
break;
> +
merge_uevq(&uevq_tmp);
>
service_uevq(&uevq_tmp);
>
}
>
condlog(3, "Terminating uev service queue");
> --
> 2.8.1.windows.1
>
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