Date: Tue, 6 Jan 2004 12:33:30 +0100
From: Christophe Saout <christophe@saout.de>
To: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Possibly wrong BIO usage in ide_multwrite
Message-ID: <20040106113330.GA5827@leto.cs.pocnet.net>
References: <1072977507.4170.14.camel@leto.cs.pocnet.net> <200401051808.49010.bzolnier@elka.pw.edu.pl> <20040105225117.GA5841@leto.cs.pocnet.net> <200401060059.52833.bzolnier@elka.pw.edu.pl>
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On Tue, Jan 06, 2004 at 12:59:52AM +0100, Bartlomiej Zolnierkiewicz wrote:

> On Monday 05 of January 2004 23:51, Christophe Saout wrote:
> > Remember? Can bio be NULL somewhere? Or what do you mean? It's our
> > scratchpad and ide_multwrite never puts a NULL bio on it.
> 
> After last sector of the whole transfer is processed ide_multwrite() will set
> it to NULL.

No, it doesn't.

                                                                                       
>			/* end early early we ran out of requests */
>			if (!bio) {
>				mcount = 0;
>			} else {
>				rq->bio = bio;
>				rq->nr_cbio_segments = bio_segments(bio);
>				rq->current_nr_sectors = bio_cur_sectors(bio);
>				rq->hard_cur_sectors = rq->current_nr_sectors;
>			}

rq->bio is only set if bio is not NULL.

>  Next IRQ is only ACK of previous datablock, no transfer happens.

You're right, the bi_idx resetting might be redundant but since bio is
never NULL an additional check is superfluous.

> Move it before the comment.

Ok. I will repost when the issue above is worked out.

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