On 23/03/22 1:15 pm, Christian König wrote: > Am 23.03.22 um 08:34 schrieb Arunpravin Paneer Selvam: >> Add a simple check to reject any size not aligned to the >> min_page_size. >> >> handle instances when size is not aligned with the min_page_size. >> Unigine Heaven has allocation requests for example required pages >> are 257 and alignment request is 256. To allocate the left over 1 >> page, continues the iteration to find the order value which is 0 >> and when it compares with min_order = 8, triggers the BUG_ON(order >> < min_order). To avoid this problem, we added a simple check to >> return -EINVAL if size is not aligned to the min_page_size. >> >> v2: Added more details to the commit description >> >> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@xxxxxxx> >> Suggested-by: Matthew Auld <matthew.auld@xxxxxxxxx> >> --- >> drivers/gpu/drm/drm_buddy.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c >> index 72f52f293249..b503c88786b0 100644 >> --- a/drivers/gpu/drm/drm_buddy.c >> +++ b/drivers/gpu/drm/drm_buddy.c >> @@ -661,6 +661,9 @@ int drm_buddy_alloc_blocks(struct drm_buddy *mm, >> if (range_overflows(start, size, mm->size)) >> return -EINVAL; >> >> + if (WARN_ON(!IS_ALIGNED(size, min_page_size))) >> + return -EINVAL; >> + > > I'm not that happy with the handling here. > > See a minimum page size larger than the requested size is perfectly > valid, it just means that the remaining pages needs to be trimmed. > > In other words when the request is to allocate 1 page with an alignment > of 256 we just need to give the remaining 255 pages back to the allocator. In one of the previous mail Matthew explained that i915 expects to return -EINVAL error code if size is not aligned to min_page_size. can we just modify in amdgpu code where we round_up the size to the min_page_size value and keep this error handling in drm_buddy.c? > > Regards, > Christian. > >> /* Actual range allocation */ >> if (start + size == end) >> return __drm_buddy_alloc_range(mm, start, size, blocks); >> >> base-commit: 056d47eaf6ea753fa2e21da31f9cbd8b721bbb7b >
