linux-kernel - [PATCH -next] drm/amdgpu: Use DIV_ROUND_UP_ULL instead of DIV_ROUND

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Message-ID: <20210610082005.86876-1-heying24@huawei.com>
Date:   Thu, 10 Jun 2021 04:20:05 -0400
From:   He Ying <heying24@...wei.com>
To:     <alexander.deucher@....com>, <christian.koenig@....com>,
        <Xinhui.Pan@....com>, <airlied@...ux.ie>, <daniel@...ll.ch>,
        <airlied@...hat.com>, <bskeggs@...hat.com>,
        <matthew.auld@...el.com>, <Ramesh.Errabolu@....com>,
        <mchehab+huawei@...nel.org>, <Dennis.Li@....com>,
        <funfunctor@...klore1984.net>
CC:     <amd-gfx@...ts.freedesktop.org>, <dri-devel@...ts.freedesktop.org>,
        <linux-kernel@...r.kernel.org>, <heying24@...wei.com>
Subject: [PATCH -next] drm/amdgpu: Use DIV_ROUND_UP_ULL instead of DIV_ROUND_UP

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.

Fixes: 6a7f76e70fac ("drm/amdgpu: add VRAM manager v2")
Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: He Ying <heying24@...wei.com>
---
 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),
-- 
2.17.1