Re: [PATCH] slab.h: Avoid using & for logical and of booleans

From: Vlastimil Babka
Date: Tue Nov 06 2018 - 03:40:14 EST


On 11/5/18 9:40 PM, Bart Van Assche wrote:
> This patch suppresses the following sparse warning:
>
> ./include/linux/slab.h:332:43: warning: dubious: x & !y
>
> Fixes: 1291523f2c1d ("mm, slab/slub: introduce kmalloc-reclaimable caches")
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Roman Gushchin <guro@xxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>

Thanks.

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

> ---
> include/linux/slab.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 918f374e7156..97d0599ddb7b 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
> * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return
> * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE
> */
> - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM;
> + return type_dma + is_reclaimable * !is_dma * KMALLOC_RECLAIM;
> }
>
> /*
>