On Fri, Nov 10, 2017 at 06:37:22AM +0000, Horia Geantă wrote:
> On 11/10/2017 12:21 AM, Herbert Xu wrote:
> > On Thu, Nov 09, 2017 at 02:37:29PM +0000, Horia Geantă wrote:
> >>
> >>>> sg_init_table(sg, np + 1);
> >> sg_mark_end() marks sg[np].
> >>
> >>>> - np--;
> >>>> + if (rem)
> >>>> + np--;
> >>>> for (k = 0; k < np; k++)
> >>>> sg_set_buf(&sg[k + 1], xbuf[k], PAGE_SIZE);
> >> In case rem == 0, last k value is np-1, thus sg[np-1+1] will be filled
> >> here with xbuf[np-1].
> >
> > No, if rem == 0, then the last k value is np-2.
> >
> Notice that np-- above the for loop is done conditionally, so in the for
> loop k takes values in [0, np-1].
> This means the for loop fills sg[1]...sg[np].
I must be missing something. In the case rem == 0, let's say
the original value of np is npo. Then at the start of the loop,
np = npo - 1, and at the last iteration, k = npo - 2, so we do
sg_set_buf(&sg[npo - 1], xbuf[npo - 2], PAGE_SIZE);
While the sg_init_table call sets the end-of-table at
sg_init_table(sg, npo + 1);
I can't see how this can be right.
Cheers,
--
Email: Herbert Xu <herb...@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
