Re: [PATCH] only irq-safe atomic ops

[Andrew Morton]

Steve Lord wrote:
> 
> On Mon, 2002-02-25 at 13:42, Andrew Morton wrote:
> > Stephen Lord wrote:
> > >
> > > Yep, bio just made it easier to get larger requests.
> > >
> >
> > Which promptly go kersplat when you feed them into
> > submit_bio():
> >
> >      BUG_ON(bio_sectors(bio) > q->max_sectors);
> >
> > Given that I'm hand-rolling a monster bio, I need to know
> > when to wrap it up and send it off, to avoid creating a bio
> > which is larger than the target device will accept.  I'm currently
> > using the below patch.   Am I right that this is missing API
> > functionality, or did I miss something?
> >
> 
> I don't run into that one, but probably because I limit xfs to
> use BIO_MAX_SECTORS, take a look at ll_rw_kio to see how that
> splits things up. This of course does not take into account
> any further restriction in an underlying queue.

Ah, yes.  I looked at that, and promptly ignored it :)

Too small, too hard-wired.  If the underlying device can
cope with megabyte requests, why restrict it to 64k?  Let's
push the envelope a bit, rather than creating more must-fixes
for 2.7.x.

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