2006-08-03 03:33:10

by Kamezawa Hiroyuki

Subject: [PATCH] memory hotadd fixes [3/5] find_next_system_ram catch range fix

find_next_system_ram() is used to find available memory resource
at onlining newly added memory.
This patch fixes following problem.

find_next_system_ram() cannot catch this case.

Resource: (start)-------------(end)
Section : (start)-------------(end)


Signed-Off-By: KAMEZAWA Hiroyuki <[email protected]>

kernel/resource.c | 3 ++-
mm/memory_hotplug.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)

Index: linux-2.6.18-rc3/kernel/resource.c
===================================================================
--- linux-2.6.18-rc3.orig/kernel/resource.c 2006-08-01 16:38:45.000000000 +0900
+++ linux-2.6.18-rc3/kernel/resource.c 2006-08-01 16:38:56.000000000 +0900
@@ -244,6 +244,7 @@

start = res->start;
end = res->end;
+ BUG_ON(start >= end);

read_lock(&resource_lock);
for (p = iomem_resource.child; p ; p = p->sibling) {
@@ -254,7 +255,7 @@
p = NULL;
break;
}
- if (p->start >= start)
+ if ((p->end >= start) && (p->start < end))
break;
}
read_unlock(&resource_lock);
Index: linux-2.6.18-rc3/mm/memory_hotplug.c
===================================================================
--- linux-2.6.18-rc3.orig/mm/memory_hotplug.c 2006-08-01 16:38:19.000000000 +0900
+++ linux-2.6.18-rc3/mm/memory_hotplug.c 2006-08-01 16:38:56.000000000 +0900
@@ -163,7 +163,7 @@
res.flags = IORESOURCE_MEM; /* we just need system ram */
section_end = res.end;

- while (find_next_system_ram(&res) >= 0) {
+ while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
start_pfn = (unsigned long)(res.start >> PAGE_SHIFT);
nr_pages = (unsigned long)
((res.end + 1 - res.start) >> PAGE_SHIFT);

2006-08-04 00:08:30

by Keith Mannthey

Subject: Re: [PATCH] memory hotadd fixes [3/5] find_next_system_ram catch range fix

On Thu, 2006-08-03 at 12:34 +0900, KAMEZAWA Hiroyuki wrote:
> find_next_system_ram() is used to find available memory resource
> at onlining newly added memory.
> This patch fixes following problem.
>
> find_next_system_ram() cannot catch this case.
>
> Resource: (start)-------------(end)
> Section : (start)-------------(end)
>
>
> Signed-Off-By: KAMEZAWA Hiroyuki <[email protected]>
>
> kernel/resource.c | 3 ++-
> mm/memory_hotplug.c | 2 +-
> 2 files changed, 3 insertions(+), 2 deletions(-)
>
> Index: linux-2.6.18-rc3/kernel/resource.c
> ===================================================================
> --- linux-2.6.18-rc3.orig/kernel/resource.c 2006-08-01 16:38:45.000000000 +0900
> +++ linux-2.6.18-rc3/kernel/resource.c 2006-08-01 16:38:56.000000000 +0900
> @@ -244,6 +244,7 @@
>
> start = res->start;
> end = res->end;
> + BUG_ON(start >= end);

BUG_ON seems a little strong for bad arguments to the function but I am
ok with it.

Thanks,
Keith