Re: [PATCH v2] drm/radeon: silence GCC warning on 32 bit

From: Christian KÃnig
Date: Tue Mar 04 2014 - 06:42:32 EST


Am 04.03.2014 10:34, schrieb Paul Bolle:
Building radeon_ttm.o on 32 bit x86 triggers a warning:
In file included from include/asm-generic/bug.h:13:0,
from [...]/arch/x86/include/asm/bug.h:38,
from include/linux/bug.h:4,
from include/drm/drm_mm.h:39,
from include/drm/drm_vma_manager.h:26,
from include/drm/ttm/ttm_bo_api.h:35,
from drivers/gpu/drm/radeon/radeon_ttm.c:32:
drivers/gpu/drm/radeon/radeon_ttm.c: In function 'radeon_ttm_gtt_read':
include/linux/kernel.h:712:17: warning: comparison of distinct pointer types lacks a cast [enabled by default]
(void) (&_min1 == &_min2); \
^
drivers/gpu/drm/radeon/radeon_ttm.c:938:22: note: in expansion of macro 'min'
ssize_t cur_size = min(size, PAGE_SIZE - off);
^

Silence this warning by using min_t(). Since cur_size will never be
negative and its upper bound is PAGE_SIZE, we can change its type to
size_t and use min_t(size_t, [...]) here.

Signed-off-by: Paul Bolle <pebolle@xxxxxxxxxx>

Reviewed-by: Christian KÃnig <christian.koenig@xxxxxxx>

---
v2: use min_t() as Ilia suggested, and convert cur_size to size_t, as
Thierry suggested.

Still compile tested only (on 32 and 64 bit x86).

drivers/gpu/drm/radeon/radeon_ttm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c
index 77f5b0c..1ce6ba6 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -935,7 +935,7 @@ static ssize_t radeon_ttm_gtt_read(struct file *f, char __user *buf,
while (size) {
loff_t p = *pos / PAGE_SIZE;
unsigned off = *pos & ~PAGE_MASK;
- ssize_t cur_size = min(size, PAGE_SIZE - off);
+ size_t cur_size = min_t(size_t, size, PAGE_SIZE - off);
struct page *page;
void *ptr;


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