Em Tue, 11 Aug 2015 12:49:40 +0200
Hans Verkuil hverk...@xs4all.nl escreveu:
On 08/07/15 16:20, Mauro Carvalho Chehab wrote:
Using memory realloc to increase the size of an array
is complex and makes harder to remove links. Also, by
embedding the link inside an array at the entity makes harder
to change the code to add interfaces, as interfaces will
also need to use links.
So, convert the links from arrays to lists.
Signed-off-by: Mauro Carvalho Chehab mche...@osg.samsung.com
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 9fb3f8958265..a95ca981aabb 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
snip
@@ -452,27 +445,21 @@ EXPORT_SYMBOL_GPL(media_entity_put);
static struct media_link *media_entity_add_link(struct media_entity
*entity)
{
- if (entity-num_links = entity-max_links) {
- struct media_link *links = entity-links;
- unsigned int max_links = entity-max_links + 2;
- unsigned int i;
+ struct media_link *link;
- links = krealloc(links, max_links * sizeof(*links), GFP_KERNEL);
- if (links == NULL)
- return NULL;
+ link = kzalloc(sizeof(*link), GFP_KERNEL);
+ if (link == NULL)
+ return NULL;
- for (i = 0; i entity-num_links; i++)
- links[i].reverse-reverse = links[i];
-
- entity-max_links = max_links;
- entity-links = links;
- }
+ link-reverse-reverse = link;
Huh? link points to a zeroed struct, so link-reverse will be NULL.
This can't work.
Are you sure this line should be here? The original code doesn't set it
either for the new link, it just updates the reverse links for the
realloced links.
You're right. I think I can just remove that line.
I had to confess that I didn't understand well that the reverse links
stuff. I mean, IMHO, the entire concept of storing a second copy of
the link, calling it as reverse on some places and as backlink
on others is messy, and I guess we should get rid of duplicating the
number of links for no good reason.
It is easy to just add the same link to a list at the other entity,
and keep the link just once in the memory.
+ INIT_LIST_HEAD(link-list);
+ list_add(entity-links, link-list);
/* Initialize graph object embedded at the new link */
graph_obj_init(entity-parent, MEDIA_GRAPH_LINK,
- entity-links[entity-num_links].graph_obj);
+ link-graph_obj);
- return entity-links[entity-num_links++];
+ return link;
}
int
Regards,
Hans
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