Re: Untangle code in bio.c

[Andrew Morton <akpm@osdl.org>]

Pavel Machek <pavel@ucw.cz> wrote:
>
> Hi!
> 
> bio.c uses quite ugly code with goto's, completely
> unneccessarily. Please apply,

I wouldn't describe this as an improvement, really.  Multiple return
statements give me hysterics.

> 
> --- clean-mm/fs/bio.c	2004-09-15 12:58:10.000000000 +0200
> +++ linux-mm/fs/bio.c	2004-09-15 13:00:51.000000000 +0200
> @@ -143,7 +143,7 @@
>  
>  	bio = mempool_alloc(bio_pool, gfp_mask);
>  	if (unlikely(!bio))
> -		goto out;
> +		return NULL;
>  
>  	bio_init(bio);
>  
> @@ -157,13 +157,11 @@
>  noiovec:
>  		bio->bi_io_vec = bvl;
>  		bio->bi_destructor = bio_destructor;
> -out:
>  		return bio;
>  	}
>  
>  	mempool_free(bio, bio_pool);
> -	bio = NULL;
> -	goto out;
> +	return NULL;
>  }

How's this look?

struct bio *bio_alloc(int gfp_mask, int nr_iovecs)
{
	struct bio *bio = mempool_alloc(bio_pool, gfp_mask);

	if (likely(bio)) {
		struct bio_vec *bvl = NULL;

		bio_init(bio);
		if (likely(nr_iovecs)) {
			unsigned long idx;

			bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx);
			if (unlikely(!bvl)) {
				mempool_free(bio, bio_pool);
				bio = NULL;
				goto out;
			}
			bio->bi_flags |= idx << BIO_POOL_OFFSET;
		}
		bio->bi_io_vec = bvl;
		bio->bi_destructor = bio_destructor;
	}
out:
	return bio;
}