Messages in this thread | | | Date | Thu, 4 Apr 2013 14:48:49 +0800 | From | Ram Pai <> | Subject | Re: [PATCH 2/3] resource: Add release_mem_region_adjustable() |
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On Wed, Apr 03, 2013 at 01:55:05PM -0600, Toshi Kani wrote: > On Wed, 2013-04-03 at 13:37 +0800, Ram Pai wrote: > > On Tue, Apr 02, 2013 at 10:17:29AM -0600, Toshi Kani wrote: > > > + while ((res = *p)) {
...snip...
> > > + if (res->start > start || res->end < end) { > > > > This check looks sub-optimal; possbily wrong, to me. if the res->start > > is greater than 'start', then obviously its sibling's start will > > also be greater than 'start'. So it will loop through all the > > resources unnecesarily. > > I think this check is necessary to check if the requested range fits > into a resource. It needs to check both sides to verify this. I will > add some comment on this check. > > > you might want something like > > > > if (start >= res->end) { > > I agree that this list is sorted, so we can optimize an error case (i.e. > no matching entry is found) with an additional check. I will add the > following check at the beginning of the while loop. > > if (res->start >= end) > break; > > I also realized that the function returns 0 when no matching entry is > found. I will change it to return -EINVAL as well.
ok. this will take care of it.
> > > > > > + p = &res->sibling; > > > + continue; > > > + } > > > + > > > + if (!(res->flags & IORESOURCE_MEM)) { > > > + ret = -EINVAL; > > > + break; > > > + } > > > + > > > + if (!(res->flags & IORESOURCE_BUSY)) { > > > + p = &res->child; > > > + continue; > > > + } > > > + > > > + if (res->start == start && res->end == end) { > > > + /* free the whole entry */ > > > + *p = res->sibling; > > > + kfree(res); > > > > This is incomplete. the prev resource's sibling should now point to > > this resource's sibling. The parent's child has to be updated if > > this resource is the first child resource. no? > > If this resource is the first child, *p is set to &parent->child. So, > it will update the parents' child.
But if the resource is not the parent's first child? will it update the previous siblings ->sibling ?
-- Ram Pai
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