From: Phong Tran
> Sent: 30 April 2019 10:01
> The cell is a pointer to __be32.
> with the be32_to_cpu a lot of clang warning show that:
>
> ./include/linux/of.h:238:37: warning: multiple unsequenced modifications
> to 'cell' [-Wunsequenced]
> r = (r << 32) | be32_to_cpu(*(cell++));
> ^~
> ./include/linux/byteorder/generic.h:95:21: note: expanded from macro
> 'be32_to_cpu'
> ^
> ./include/uapi/linux/byteorder/little_endian.h:40:59: note: expanded
> from macro '__be32_to_cpu'
> ^
> ./include/uapi/linux/swab.h:118:21: note: expanded from macro '__swab32'
> ___constant_swab32(x) : \
> ^
> ./include/uapi/linux/swab.h:18:12: note: expanded from macro
> '___constant_swab32'
> (((__u32)(x) & (__u32)0x000000ffUL) << 24) | \
> ^
>
> Signed-off-by: Phong Tran <tranmanphong@xxxxxxxxx>
> ---
> include/linux/of.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/of.h b/include/linux/of.h
> index e240992e5cb6..1c35fc8f19b0 100644
> --- a/include/linux/of.h
> +++ b/include/linux/of.h
> @@ -235,7 +235,7 @@ static inline u64 of_read_number(const __be32 *cell, int size)
> {
> u64 r = 0;
> while (size--)
> - r = (r << 32) | be32_to_cpu(*(cell++));
> + r = (r << 32) | be32_to_cpup(cell++);
> return r;
That is a very strange loop.
It is probably equivalent to:
r = be32_to_cpu(*cell);
if (size)
r = r << 32 | be32_to_cpu(cell[1]);
return r;
In any case replacing the while with (say):
for (; size--; cell++)
r = (r << 32) | be32_to_cpu(*cell);
would remove the ambiguity.
David
-
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