From: Laurent Pinchart
> Sent: 13 March 2023 18:12
>
> Hi Benjamin,
>
> Thank you for the patch.
>
> On Mon, Mar 13, 2023 at 02:59:14PM +0100, Benjamin Gaignard wrote:
> > Replacing bufs array by a list allows to remove the 32 buffers
> > limit per queue.
Is the limit actually a problem?
Arrays of pointers have locking and caching advantages over
linked lists.
...
> > @@ -1239,8 +1242,12 @@ static inline void vb2_clear_last_buffer_dequeued(struct vb2_queue *q)
> > static inline struct vb2_buffer *vb2_get_buffer(struct vb2_queue *q,
> > unsigned int index)
> > {
> > - if (index < q->num_buffers)
> > - return q->bufs[index];
> > + struct vb2_buffer *vb;
> > +
> > + list_for_each_entry(vb, &q->allocated_bufs, allocated_entry)
> > + if (vb->index == index)
> > + return vb;
> > +
> > return NULL;
You really don't want to be doing that....
There are schemes for unbounded arrays.
Scanning a linked list isn't a very good one.
David
-
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