Re: [PATCH] block: fail unaligned bio from submit_bio_noacct()

[Christoph Hellwig <hch@infradead.org>]

On Thu, Mar 21, 2024 at 09:16:34PM +0800, Ming Lei wrote:
> For any bio with data, its start sector and size have to be aligned with
> the queue's logical block size.
> 
> This rule is obvious, but there is still user which may send unaligned
> bio to block layer, and it is observed that dm-integrity can do that,
> and cause double free of driver's dma meta buffer.
> 
> So failfast unaligned bio from submit_bio_noacct() for avoiding more
> troubles.

I've been wanting to do that for the next merge window, as the lack of
this check is kinda stunning.  Note that we have open coded versions
of it in __blkdev_issue_dicard and blkdev_issue_zeroout that can go
away now.

> +static bool bio_check_alignment(struct bio *bio, struct request_queue *q)
> +{
> +	unsigned int bs = q->limits.logical_block_size;
> +	unsigned int size = bio->bi_iter.bi_size;

This should just use bdev_logical_block_size() on bio->bi_bdev.