On 3/30/22 23:47, Rob Clark wrote:
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> Combines duplicate vma lookup in the get_and_pin path.
>
> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/msm/msm_gem.c | 50 ++++++++++++++++++-----------------
> 1 file changed, 26 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gem.c b/drivers/gpu/drm/msm/msm_gem.c
> index deafae6feaa8..218744a490a4 100644
> --- a/drivers/gpu/drm/msm/msm_gem.c
> +++ b/drivers/gpu/drm/msm/msm_gem.c
> @@ -376,39 +376,40 @@ put_iova_vmas(struct drm_gem_object *obj)
> }
> }
>
> -static int get_iova_locked(struct drm_gem_object *obj,
> - struct msm_gem_address_space *aspace, uint64_t *iova,
> +static struct msm_gem_vma *get_vma_locked(struct drm_gem_object *obj,
> + struct msm_gem_address_space *aspace,
> u64 range_start, u64 range_end)
> {
> struct msm_gem_vma *vma;
> - int ret = 0;
>
> GEM_WARN_ON(!msm_gem_is_locked(obj));
>
> vma = lookup_vma(obj, aspace);
>
> if (!vma) {
> + int ret;
> +
> vma = add_vma(obj, aspace);
> if (IS_ERR(vma))
> - return PTR_ERR(vma);
> + return vma;
>
> ret = msm_gem_init_vma(aspace, vma, obj->size,
> range_start, range_end);
> if (ret) {
You're allocation range_start -> range_end
> del_vma(vma);
> - return ret;
> + return ERR_PTR(ret);
> }
> + } else {
> + GEM_WARN_ON(vma->iova < range_start);
> + GEM_WARN_ON((vma->iova + obj->size) > range_end);
and then comparing range_start -> range_start + obj->size, hence you're
assuming that range_end always equals to obj->size during the allocation.
I'm not sure what is the idea here.. this looks inconsistent. I think
you wanted to write:
GEM_WARN_ON(vma->iova < range_start);
GEM_WARN_ON(vma->iova + (vma->node.size << PAGE_SHIFT) > range_end);
But is it really useful to check whether the new range is inside of the
old range? Shouldn't it be always a error to change the IOVA range
without reallocating vma?
I'd expect to see:
GEM_WARN_ON(vma->iova != range_start);
GEM_WARN_ON(vma->iova + (vma->node.size << PAGE_SHIFT) != range_end);
and then error out if range mismatches.
