[igt-dev] [PATCH i-g-t] Return allocated size in gem_create_in_memory_regions() and friends

[Dixit, Ashutosh]

On Mon, 27 Sep 2021 23:52:41 -0700, Zbigniew Kempczyński wrote:
>
> > diff --git a/lib/intel_bufops.c b/lib/intel_bufops.c
> > index d1395c1605d..52794c1ac10 100644
> > --- a/lib/intel_bufops.c
> > +++ b/lib/intel_bufops.c
> > @@ -819,7 +819,7 @@ static void __intel_buf_init(struct buf_ops *bops,
> >	if (handle)
> >		buf->handle = handle;
> >	else {
> > -		if (!__gem_create_in_memory_regions(bops->fd, &handle, size, region))
> > +		if (!__gem_create_in_memory_regions(bops->fd, &handle, &size, region))
> >			buf->handle = handle;
> >		else
> >			buf->handle = gem_create(bops->fd, size);
>
> As size can be different we pass we should update buf->size accordingly.
> Look at few lines above:
>
>	/* Store real bo size to avoid mistakes in calculating it again */
>	buf->size = size;
>
> I think these lines can be moved at the bottom of the condition.
>
> buf->size is returned as a call to intel_buf_bo_size() and used in
> intel_bb_add_object(). This can be important for no-reloc mode to avoid
> overlapping object on softpin and hitting -ENOSPC.

I have a new patch reverting part of the changes done in 22643ce4014a:

https://patchwork.freedesktop.org/series/95376/

In this context I want to check regarding the above change again: should we
be setting buf->size above to the allocated size or to the requested size,
in case the two are different? Currently the code (even after the new
patch) is setting it to the allocated size which might be >= the requested
size. Thanks.