On 3/31/22 21:52, Dmitry Osipenko wrote:
> ...
>> +/*
>> + * Get the requested iova but don't pin it. Fails if the requested iova is
>> + * not available. Doesn't need a put because iovas are currently valid for
>> + * the life of the object.
>> + *
>> + * Setting an iova of zero will clear the vma.
>> + */
>> +int msm_gem_set_iova(struct drm_gem_object *obj,
>> + struct msm_gem_address_space *aspace, uint64_t iova)
>> +{
>> + int ret = 0;
>
> nit: No need to initialize the ret
>
>> + msm_gem_lock(obj);
>> + if (!iova) {
>> + ret = clear_iova(obj, aspace);
>> + } else {
>> + struct msm_gem_vma *vma;
>> + vma = get_vma_locked(obj, aspace, iova, iova + obj->size);
>> + if (IS_ERR(vma)) {
>> + ret = PTR_ERR(vma);
>> + } else if (GEM_WARN_ON(vma->iova != iova)) {
>> + clear_iova(obj, aspace);
>> + ret = -ENOSPC;
>
> The (vma->iova != iova) means that vma is already set, but to a
> different address. Is -ENOSPC really appropriate here? -EBUSY or -EINVAL
> looks more natural to me.
>
>> + }
>> + }
>> + msm_gem_unlock(obj);
>> +
>> + return ret;
>> +}
>> +
>> /*
>> * Unpin a iova by updating the reference counts. The memory isn't actually
>> * purged until something else (shrinker, mm_notifier, destroy, etc) decides
>> diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
>> index 38d66e1248b1..efa2e5c19f1e 100644
>> --- a/drivers/gpu/drm/msm/msm_gem.h
>> +++ b/drivers/gpu/drm/msm/msm_gem.h
>> @@ -38,6 +38,12 @@ struct msm_gem_address_space {
>>
>> /* @faults: the number of GPU hangs associated with this address space */
>> int faults;
>> +
>> + /** @va_start: lowest possible address to allocate */
>> + uint64_t va_start;
>> +
>> + /** @va_size: the size of the address space (in bytes) */
>> + uint64_t va_size;
>> };
>>
>> struct msm_gem_address_space *
>> @@ -144,6 +150,8 @@ struct msm_gem_vma *msm_gem_get_vma_locked(struct drm_gem_object *obj,
>> struct msm_gem_address_space *aspace);
>> int msm_gem_get_iova(struct drm_gem_object *obj,
>> struct msm_gem_address_space *aspace, uint64_t *iova);
>> +int msm_gem_set_iova(struct drm_gem_object *obj,
>> + struct msm_gem_address_space *aspace, uint64_t iova);
>> int msm_gem_get_and_pin_iova_range(struct drm_gem_object *obj,
>> struct msm_gem_address_space *aspace, uint64_t *iova,
>> u64 range_start, u64 range_end);
> nit: There is an odd mix of uint64_t and u64 (and alike) in the MSM code
> :) The uint64_t variant shouldn't be used by kernel code in general and
> checkpatch should want about it.
s/want/warn/
