Re: [PATCH] fix small highmem bio bounce bvec handling glitch

[Christophe Saout]

Am Do, den 26.02.2004 schrieb Jens Axboe um 16:10:

> > --- linux.orig/mm/highmem.c	2004-01-21 19:08:45.000000000 +0100
> > +++ linux/mm/highmem.c	2004-02-26 15:47:14.574722576 +0100
> > @@ -294,7 +294,12 @@
> >  		if (tovec->bv_page == fromvec->bv_page)
> >  			continue;
> >  
> > -		vfrom = page_address(fromvec->bv_page) + fromvec->bv_offset;
> > +		/*
> > +		 * fromvec->bv_offset and fromvec->bv_len might have been
> > +		 * modified by the block layer, so use the original copy,
> > +		 * bounce_copy_vec already uses tovec->bv_len
> > +		 */
> > +		vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
> >  
> >  		bounce_copy_vec(tovec, vfrom);
> 
> Irk yes, that's is pretty nasty, I really wish we could avoid screwing
> with vec entries

What about a bio->bi_bvec_done field?

> (it's pretty obscure for bio clones, too)...

Yes, I noticed that dm-crypt also does the same mistake for reads. I'm
going to change it too (easily accomplished).


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