[PATCH v2 libdrm] amdgpu: Eliminate void* arithmetic in amdgpu_find_bo_by_cpu_mapping

[Zhang, Jerry]

 Reviewed-by: Junwei Zhang <Jerry.Zhang at amd.com>

Regards,
Jerry(Junwei Zhang)

________________________________________
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of Michel Dänzer <michel at daenzer.net>
Sent: Thursday, August 16, 2018 9:54:29 PM
To: amd-gfx at lists.freedesktop.org
Subject: [PATCH v2 libdrm] amdgpu: Eliminate void* arithmetic in amdgpu_find_bo_by_cpu_mapping

From: Michel Dänzer <michel.daenzer at amd.com>

Arithmetic using void* pointers isn't defined by the C standard, only as
a GCC extension. Avoids compiler warnings:

../../amdgpu/amdgpu_bo.c: In function ‘amdgpu_find_bo_by_cpu_mapping’:
../../amdgpu/amdgpu_bo.c:554:48: warning: pointer of type ‘void *’ used in arithmetic [-Wpointer-arith]
   if (cpu >= bo->cpu_ptr && cpu < (bo->cpu_ptr + bo->alloc_size))
                                                ^
../../amdgpu/amdgpu_bo.c:561:23: warning: pointer of type ‘void *’ used in subtraction [-Wpointer-arith]
   *offset_in_bo = cpu - bo->cpu_ptr;
                       ^

v2: Use uintptr_t instead of char*, don't change function signature
    (Junwei Zhang)

Fixes: 4d454424e1f2 ("amdgpu: add a function to find bo by cpu mapping
                     (v2)")
Signed-off-by: Michel Dänzer <michel.daenzer at amd.com>
---
 amdgpu/amdgpu_bo.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/amdgpu/amdgpu_bo.c b/amdgpu/amdgpu_bo.c
index 86d1c143..8efd014e 100644
--- a/amdgpu/amdgpu_bo.c
+++ b/amdgpu/amdgpu_bo.c
@@ -551,14 +551,15 @@ int amdgpu_find_bo_by_cpu_mapping(amdgpu_device_handle dev,
                bo = handle_table_lookup(&dev->bo_handles, i);
                if (!bo || !bo->cpu_ptr || size > bo->alloc_size)
                        continue;
-               if (cpu >= bo->cpu_ptr && cpu < (bo->cpu_ptr + bo->alloc_size))
+               if (cpu >= bo->cpu_ptr &&
+                   cpu < (void*)((uintptr_t)bo->cpu_ptr + bo->alloc_size))
                        break;
        }

        if (i < dev->bo_handles.max_key) {
                atomic_inc(&bo->refcount);
                *buf_handle = bo;
-               *offset_in_bo = cpu - bo->cpu_ptr;
+               *offset_in_bo = (uintptr_t)cpu - (uintptr_t)bo->cpu_ptr;
        } else {
                *buf_handle = NULL;
                *offset_in_bo = 0;
--
2.18.0

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