From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [PATCH 2/2] block: unify flags for struct bio and struct request Date: Fri, 18 Jun 2010 19:07:53 +1000 Message-ID: <20100618090753.GF6138@laptop> References: <20100618074704.GB13358@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: axboe@kernel.dk, linux-fsdevel@vger.kernel.org To: Christoph Hellwig Return-path: Received: from cantor.suse.de ([195.135.220.2]:37074 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758129Ab0FRJH5 (ORCPT ); Fri, 18 Jun 2010 05:07:57 -0400 Content-Disposition: inline In-Reply-To: <20100618074704.GB13358@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, Jun 18, 2010 at 09:47:04AM +0200, Christoph Hellwig wrote: > Remove the current bio flags and reuse the request flags for the bio, too. > This allows to more easily trace the type of I/O from the filesystem > down to the block driver. There were two flags in the bio that were > missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've > renamed two request flags that had a superflous RW in them. > > Note that the flags are in bio.h despite having the REQ_ name - as > blkdev.h includes bio.h that is the only way to go for now. > > Signed-off-by: Christoph Hellwig > > Index: linux-2.6/block/blk-core.c > =================================================================== > --- linux-2.6.orig/block/blk-core.c 2010-06-17 13:21:18.000000000 +0200 > +++ linux-2.6/block/blk-core.c 2010-06-17 13:26:55.958005535 +0200 > @@ -1139,27 +1139,9 @@ void init_request_from_bio(struct reques > { > req->cpu = bio->bi_comp_cpu; > req->cmd_type = REQ_TYPE_FS; > - > - /* > - * Inherit FAILFAST from bio (for read-ahead, and explicit > - * FAILFAST). FAILFAST flags are identical for req and bio. > - */ > - if (bio_rw_flagged(bio, BIO_RW_AHEAD)) > + req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK; > + if (bio->bi_rw & REQ_RAHEAD) > req->cmd_flags |= REQ_FAILFAST_MASK; > - else > - req->cmd_flags |= bio->bi_rw & REQ_FAILFAST_MASK; > - > - if (bio_rw_flagged(bio, BIO_RW_DISCARD)) > - req->cmd_flags |= REQ_DISCARD; > - if (bio_rw_flagged(bio, BIO_RW_BARRIER)) > - req->cmd_flags |= REQ_HARDBARRIER; > - if (bio_rw_flagged(bio, BIO_RW_SYNCIO)) > - req->cmd_flags |= REQ_RW_SYNC; > - if (bio_rw_flagged(bio, BIO_RW_META)) > - req->cmd_flags |= REQ_RW_META; > - if (bio_rw_flagged(bio, BIO_RW_NOIDLE)) > - req->cmd_flags |= REQ_NOIDLE; Much better for branches and icache. Any reason not to make REQ_RAHEAD include REQ_FAILFAST_MASK?