Re: [PATCH 2/4] block: factor out a bio_await helper

[Bart Van Assche <bvanassche@acm.org>]

On 4/1/26 7:03 AM, Christoph Hellwig wrote:
> +/**
> + * bio_await - call a function on a bio, and wait until it completes
> + * @bio:	the bio which describes the I/O
> + * @kick:	function called to "kick off" the bio
> + * @priv:	private data passed to @kick.
> + *
> + * Wait for the bio as well as any bio chained off it after executing the
> + * passed in callback @kick.  The wait for the bio is set up before calling
> + * @kick to ensure that the completion is captured.  If @kick is %NULL,
> + * submit_bio() is used instead to submit the bio.
> + *
> + * Note: this overrides the bi_private and bi_end_io fields in the bio.
> + */
> +void bio_await(struct bio *bio, void *priv,
> +	       void (*kick)(struct bio *bio, void *priv))

Please consider swapping the @priv and @kick arguments because that's
the argument order used elsewhere in the Linux kernel for callback
function pointers and their private data pointer.

>   int submit_bio_wait(struct bio *bio)
>   {
> -	DECLARE_COMPLETION_ONSTACK_MAP(done,
> -			bio->bi_bdev->bd_disk->lockdep_map);
> -
> -	bio->bi_private = &done;
> -	bio->bi_end_io = bio_wait_end_io;
> -	bio->bi_opf |= REQ_SYNC;
> -	submit_bio(bio);
> -	blk_wait_io(&done);
> -
> +	bio_await(bio, NULL, NULL);
>   	return blk_status_to_errno(bio->bi_status);
>   }
>   EXPORT_SYMBOL(submit_bio_wait);

What happened to the bio->bi_opf |= REQ_SYNC statement? Shouldn't that 
statement be preserved?

Otherwise this patch looks good to me.

Thanks,

Bart.