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Date: Wed, 15 Sep 2004 13:55:44 +0200
From: Jens Axboe <axboe@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: Pavel Machek <pavel@ucw.cz>, linux-kernel@vger.kernel.org,
       trivial@rustcorp.com.au
Subject: Re: Untangle code in bio.c
Message-ID: <20040915115544.GB4111@suse.de>
References: <20040915111802.GA20222@elf.ucw.cz> <20040915043644.4fb58787.akpm@osdl.org>
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On Wed, Sep 15 2004, Andrew Morton wrote:
> 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.

Me neither...

> > --- 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;
> }

Same semantics and it looks good to me.

-- 
Jens Axboe