[RFC 3/3] dma-contiguous: Type cast MAX_ORDER as unsigned int

Anshuman Khandual anshuman.khandual at arm.com
Thu Feb 4 02:01:24 EST 2021


Type cast MAX_ORDER as unsigned int to fix the following build warning.

In file included from ./include/linux/kernel.h:14,
                 from ./include/asm-generic/bug.h:20,
                 from ./arch/arm64/include/asm/bug.h:26,
                 from ./include/linux/bug.h:5,
                 from ./include/linux/mmdebug.h:5,
                 from ./arch/arm64/include/asm/memory.h:166,
                 from ./arch/arm64/include/asm/page.h:42,
                 from kernel/dma/contiguous.c:46:
kernel/dma/contiguous.c: In function ‘rmem_cma_setup’:
./include/linux/minmax.h:18:28: warning: comparison of distinct pointer
types lacks a cast
  (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                            ^~
./include/linux/minmax.h:32:4: note: in expansion of macro ‘__typecheck’
   (__typecheck(x, y) && __no_side_effects(x, y))
    ^~~~~~~~~~~
./include/linux/minmax.h:42:24: note: in expansion of macro ‘__safe_cmp’
  __builtin_choose_expr(__safe_cmp(x, y), \
                        ^~~~~~~~~~
./include/linux/minmax.h:58:19: note: in expansion of macro
‘__careful_cmp’
 #define max(x, y) __careful_cmp(x, y, >)
                   ^~~~~~~~~~~~~
kernel/dma/contiguous.c:402:35: note: in expansion of macro ‘max’
  phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);

Cc: Christoph Hellwig <hch at lst.de>
Cc: Marek Szyprowski <m.szyprowski at samsung.com>
Cc: Robin Murphy <robin.murphy at arm.com>
Cc: iommu at lists.linux-foundation.org
Cc: linux-kernel at vger.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
---
 kernel/dma/contiguous.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 3d63d91cba5c..1c2782349d71 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -399,7 +399,7 @@ static const struct reserved_mem_ops rmem_cma_ops = {
 
 static int __init rmem_cma_setup(struct reserved_mem *rmem)
 {
-	phys_addr_t align = PAGE_SIZE << max(MAX_ORDER - 1, pageblock_order);
+	phys_addr_t align = PAGE_SIZE << max((unsigned int)MAX_ORDER - 1, pageblock_order);
 	phys_addr_t mask = align - 1;
 	unsigned long node = rmem->fdt_node;
 	bool default_cma = of_get_flat_dt_prop(node, "linux,cma-default", NULL);
-- 
2.20.1




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