Re: [PATCH 1/1] staging: android: ion: fixes spars warning cast to restricted gfp_t

[Laura Abbott <labbott@redhat.com>]

On 12/21/2015 03:24 AM, Bijosh Thykkoottathil wrote:
> From: Bijosh Thykkoottathil <bijosh.thyks@gmail.com>
>
> This patch fixes following sparse warnings:
>
> drivers/staging/android/ion/ion.c:1475:21: warning: incorrect type in assignment (different base types)
> drivers/staging/android/ion/ion.c:1475:21:    expected restricted gfp_t [usertype] gfp_mask
> drivers/staging/android/ion/ion.c:1475:21:    got int
> drivers/staging/android/ion/ion.c:1493:21: warning: incorrect type in assignment (different base types)
> drivers/staging/android/ion/ion.c:1493:21:    expected restricted gfp_t [usertype] gfp_mask
> drivers/staging/android/ion/ion.c:1493:21:    got int
>
> Signed-off-by: Bijosh Thykkoottathil <bijosh.thyks@gmail.com>
> ---
>   drivers/staging/android/ion/ion.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
> index e237e9f..f986a58 100644
> --- a/drivers/staging/android/ion/ion.c
> +++ b/drivers/staging/android/ion/ion.c
> @@ -1472,7 +1472,7 @@ static int debug_shrink_set(void *data, u64 val)
>   	struct shrink_control sc;
>   	int objs;
>
> -	sc.gfp_mask = -1;
> +	sc.gfp_mask = (__force gfp_t)(-1);
>   	sc.nr_to_scan = val;

-1 doesn't actually make much sense here. I'd rather see this changed to be an
appropriate GFP flag rather than just casting it away, probably
GFP_HIGHUSER. If you'd like to fix this up, make sure to double check
that the shrinking behavior remains the same (similar number of low and high
pages are reclaimed).

Thanks,
Laura