Re: [PATCH -next] drm/amdgpu: Use DIV_ROUND_UP_ULL instead of DIV_ROUND_UP

[He Ying]

Hello,


在 2021/6/10 16:20, Christian König 写道:
> Am 10.06.21 um 10:20 schrieb He Ying:
> > When compiling the kernel for MIPS with CONFIG_DRM_AMDGPU = y, errors 
> > are
> > encountered as follows:
> >
> > drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.o: In function 
> > `amdgpu_vram_mgr_new':
> > amdgpu_vram_mgr.c:(.text+0x740): undefined reference to `__udivdi3'
> >
> > Making a 64 bit division by a/b (a is uint64_t) is not supported by 
> > default
> > in linux kernel space. Instead, using do_div is OK for this 
> > situation. For
> > this problem, using DIV_ROUND_UP_ULL instead of DIV_ROUND_UP is better.
>
> Already fixed by this patch in drm-next:
>
> commit 691cf8cd7a531dbfcc29d09a23c509a86fd9b24f
> Author: Dave Airlie <airlied@xxxxxxxxxx>
> Date:   Thu Jun 10 12:59:00 2021 +1000
>
>     drm/amdgpu: use correct rounding macro for 64-bit
>
>     This fixes 32-bit arm build due to lack of 64-bit divides.

OK. Sigh.

Before sending my patch, I searched patches in https://lore.kernel.org/lkml/

but I didn't find this patch. How can I find whether my patch is duplicated

before sending it? Any suggestions?


Thanks.

> Regards,
> Christian.
>
> > Fixes: 6a7f76e70fac ("drm/amdgpu: add VRAM manager v2")
> > Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> > Signed-off-by: He Ying <heying24@xxxxxxxxxx>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c 
> > b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> > index 9a6df02477ce..436ec246a7da 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> > @@ -407,7 +407,7 @@ static int amdgpu_vram_mgr_new(struct 
> > ttm_resource_manager *man,
> >   #endif
> >           pages_per_node = max_t(uint32_t, pages_per_node,
> >                          tbo->page_alignment);
> > -        num_nodes = DIV_ROUND_UP(PFN_UP(mem_bytes), pages_per_node);
> > +        num_nodes = DIV_ROUND_UP_ULL(PFN_UP(mem_bytes), 
> > pages_per_node);
> >       }
> >         node = kvmalloc(struct_size(node, mm_nodes, num_nodes),
>
> .