On Thu, Feb 11, 2021 at 11:52:11AM +0530, Anshuman Khandual wrote:
> 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@xxxxxx>
> Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
> Cc: Robin Murphy <robin.murphy@xxxxxxx>
> Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
> ---
> 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);
MAX_ORDER and pageblock_order should be the same type. So either fix
MAX_ORDER to be an unsigned constant, which would be fundamentally
the right thing to do but might cause some fallout, or turn
pageblock_order into an int, which is probably much either as the stub
define of it already has an integer type derived from MAX_ORDER as well.
