Re: Subject: [PATCH 004/009]: md. chunk size check

[Neil Brown <neilb@suse.de>]

On Tuesday May 19, raziebe@gmail.com wrote:
> 	md fixes
> 1.move chunk size check from md responsibility to each run function in each raid.
> 2.replace chunk size power 2 code calculations by a regular division.

Thanks.
I reordered this patch so that it comes *after* the patches which add
checks to the other raid levels.  That way the code is correct after
every patch.

NeilBrown



> 
>  md.c |   22 ++++++++++------------
>  1 file changed, 10 insertions(+), 12 deletions(-)
> 
> Signed-off-by: raziebe@gmail.com
> ---
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 279007a..3ac8813 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -444,8 +444,12 @@ static sector_t calc_num_sectors(mdk_rdev_t *rdev, unsigned chunk_size)
>  {
>  	sector_t num_sectors = rdev->sb_start;
>  
> -	if (chunk_size)
> -		num_sectors &= ~((sector_t)chunk_size/512 - 1);
> +	if (chunk_size) {
> +		sector_t chunk_sects = chunk_size>>9;
> +		sector_t x = num_sectors;
> +		sector_div(x, chunk_sects);
> +		num_sectors = x*chunk_sects;
> +	}
>  	return num_sectors;
>  }
>  
> @@ -3518,7 +3522,8 @@ min_sync_store(mddev_t *mddev, const char *buf, size_t len)
>  
>  	/* Must be a multiple of chunk_size */
>  	if (mddev->chunk_size) {
> -		if (min & (sector_t)((mddev->chunk_size>>9)-1))
> +		sector_t temp = min;
> +		if (sector_div(temp, (mddev->chunk_size>>9)))
>  			return -EINVAL;
>  	}
>  	mddev->resync_min = min;
> @@ -3555,7 +3560,8 @@ max_sync_store(mddev_t *mddev, const char *buf, size_t len)
>  
>  		/* Must be a multiple of chunk_size */
>  		if (mddev->chunk_size) {
> -			if (max & (sector_t)((mddev->chunk_size>>9)-1))
> +			sector_t temp = max;
> +			if (sector_div(temp, (mddev->chunk_size>>9)))
>  				return -EINVAL;
>  		}
>  		mddev->resync_max = max;
> @@ -3996,14 +4002,6 @@ static int do_md_run(mddev_t * mddev)
>  				chunk_size, MAX_CHUNK_SIZE);
>  			return -EINVAL;
>  		}
> -		/*
> -		 * chunk-size has to be a power of 2
> -		 */
> -		if ( (1 << ffz(~chunk_size)) != chunk_size) {
> -			printk(KERN_ERR "chunk_size of %d not valid\n", chunk_size);
> -			return -EINVAL;
> -		}
> -
>  		/* devices must have minimum size of one chunk */
>  		list_for_each_entry(rdev, &mddev->disks, same_set) {
>  			if (test_bit(Faulty, &rdev->flags))
> 
> 
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