Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265580AbUABOAl (ORCPT ); Fri, 2 Jan 2004 09:00:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265579AbUABOAk (ORCPT ); Fri, 2 Jan 2004 09:00:40 -0500 Received: from ns.virtualhost.dk ([195.184.98.160]:48771 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S265580AbUABN7Y (ORCPT ); Fri, 2 Jan 2004 08:59:24 -0500 Date: Fri, 2 Jan 2004 14:59:21 +0100 From: Jens Axboe To: Peter Osterlund Cc: Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: ext2 on a CD-RW Message-ID: <20040102135921.GB20572@suse.de> References: <20040101162427.4c6c020b.akpm@osdl.org> <1073034412.4429.1.camel@laptop.fenrus.com> <20040102105915.GO5523@suse.de> <20040102121904.GQ5523@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2581 Lines: 56 On Fri, Jan 02 2004, Peter Osterlund wrote: > Jens Axboe writes: > > > I just looked but could not find anything about it, there's been some > > talk on this list. But it doesn't look like it ever got documented in > > text writing. That needs to be fixed for sure, thanks for the patch. It > > probably wants documenting in fs/bio.c:bio_add_page() too. > > OK, here is an updated patch. > > Improved documentation for blk_queue_merge_bvec() and bio_add_page(). > > > linux-petero/drivers/block/ll_rw_blk.c | 8 +++++--- > linux-petero/fs/bio.c | 4 +++- > 2 files changed, 8 insertions(+), 4 deletions(-) > > diff -puN drivers/block/ll_rw_blk.c~block-api-doc drivers/block/ll_rw_blk.c > --- linux/drivers/block/ll_rw_blk.c~block-api-doc 2004-01-02 13:54:38.000000000 +0100 > +++ linux-petero/drivers/block/ll_rw_blk.c 2004-01-02 13:55:50.000000000 +0100 > @@ -173,9 +173,11 @@ EXPORT_SYMBOL(blk_queue_prep_rq); > * are dynamic, and thus we have to query the queue whether it is ok to > * add a new bio_vec to a bio at a given offset or not. If the block device > * has such limitations, it needs to register a merge_bvec_fn to control > - * the size of bio's sent to it. Per default now merge_bvec_fn is defined for > - * a queue, and only the fixed limits are honored. > - * > + * the size of bio's sent to it. Note that a block device *must* allow a > + * single page to be added to an empty bio. The block device driver may want > + * to use the bio_split() function to deal with these bio's. Per default > + * no merge_bvec_fn is defined for a queue, and only the fixed limits are > + * honored. > */ > void blk_queue_merge_bvec(request_queue_t *q, merge_bvec_fn *mbfn) > { > diff -puN fs/bio.c~block-api-doc fs/bio.c > --- linux/fs/bio.c~block-api-doc 2004-01-02 14:00:13.000000000 +0100 > +++ linux-petero/fs/bio.c 2004-01-02 14:37:41.000000000 +0100 > @@ -290,7 +290,9 @@ int bio_get_nr_vecs(struct block_device > * > * Attempt to add a page to the bio_vec maplist. This can fail for a > * number of reasons, such as the bio being full or target block > - * device limitations. > + * device limitations. The target block device must not disallow bio's That may not be unparsable, but I'll remove the double negative :). Otherwise comitted, thanks. -- Jens Axboe - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/