Re: [PATCH] md: raid10: remove VLAIS

[Shaohua Li <shli@kernel.org>]

On Thu, Oct 05, 2017 at 11:28:47AM -0700, Matthias Kaehlcke wrote:
> The raid10 driver can't be built with clang since it uses a variable
> length array in a structure (VLAIS):
> 
> drivers/md/raid10.c:4583:17: error: fields must have a constant size:
>   'variable length array in structure' extension will never be supported
> 
> Allocate the r10bio struct with kmalloc instead of using the VLAIS
> construct.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>  drivers/md/raid10.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 374df5796649..9616163eaf8c 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -4578,15 +4578,16 @@ static int handle_reshape_read_error(struct mddev *mddev,
>  	/* Use sync reads to get the blocks from somewhere else */
>  	int sectors = r10_bio->sectors;
>  	struct r10conf *conf = mddev->private;
> -	struct {
> -		struct r10bio r10_bio;
> -		struct r10dev devs[conf->copies];
> -	} on_stack;
> -	struct r10bio *r10b = &on_stack.r10_bio;
> +	struct r10bio *r10b;
>  	int slot = 0;
>  	int idx = 0;
>  	struct page **pages;
>  
> +	r10b = kmalloc(sizeof(*r10b) +
> +	       sizeof(struct r10dev) * conf->copies, GFP_KERNEL);
> +	if (!r10b)
> +		return -ENOMEM;

I'll apply this patch with 'set_bit(MD_RECOVERY_INTR, &mddev->recovery);' added here, thanks!

> +
>  	/* reshape IOs share pages from .devs[0].bio */
>  	pages = get_resync_pages(r10_bio->devs[0].bio)->pages;
>  
> @@ -4635,11 +4636,13 @@ static int handle_reshape_read_error(struct mddev *mddev,
>  			/* couldn't read this block, must give up */
>  			set_bit(MD_RECOVERY_INTR,
>  				&mddev->recovery);
> +			kfree(r10b);
>  			return -EIO;
>  		}
>  		sectors -= s;
>  		idx++;
>  	}
> +	kfree(r10b);
>  	return 0;
>  }
>  
> -- 
> 2.14.2.920.gcf0c67979c-goog
>