Re: [PATCH v3 04/10] block: respect bio_required_sector_alignment() in blk-crypto-fallback

[Eric Biggers]

On Fri, Jun 04, 2021 at 07:58:54PM +0000, Satya Tangirala wrote:
> Make blk_crypto_split_bio_if_needed() respect
> bio_required_sector_alignment() when calling bio_split(). Without this,
> blk-crypto-fallback could possibly split a bio in the middle of a data
> unit, and the resulting bios can no longer be encrypted (since encryption
> can only be done on complete crypto data units).
> 
> Signed-off-by: Satya Tangirala <satyat@xxxxxxxxxx>
> ---
>  block/blk-crypto-fallback.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/block/blk-crypto-fallback.c b/block/blk-crypto-fallback.c
> index c322176a1e09..85c813ef670b 100644
> --- a/block/blk-crypto-fallback.c
> +++ b/block/blk-crypto-fallback.c
> @@ -19,6 +19,7 @@
>  #include <linux/module.h>
>  #include <linux/random.h>
>  
> +#include "blk.h"
>  #include "blk-crypto-internal.h"
>  
>  static unsigned int num_prealloc_bounce_pg = 32;
> @@ -225,6 +226,8 @@ static bool blk_crypto_split_bio_if_needed(struct bio **bio_ptr)
>  	if (num_sectors < bio_sectors(bio)) {
>  		struct bio *split_bio;
>  
> +		num_sectors = round_down(num_sectors,
> +					 bio_required_sector_alignment(bio));
>  		split_bio = bio_split(bio, num_sectors, GFP_NOIO,
>  				      &crypto_bio_split);
>  		if (!split_bio) {
> -- 

Reviewed-by: Eric Biggers <ebiggers@xxxxxxxxxx>