memory unplug: memory hotplug cleanup
A clean up patch for "scanning memory resource [start, end)" operation.
Now, find_next_system_ram() function is used in memory hotplug, but this
interface is not easy to use and codes are complicated.
This patch adds walk_memory_resouce(start,len,arg,func) function.
The function 'func' is called per valid memory resouce range in [start,pfn).
[pbadari@us.ibm.com: Error handling in walk_memory_resource()]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/resource.c b/kernel/resource.c
index 9bd14fd..a358142 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -234,7 +234,7 @@
* the caller must specify res->start, res->end, res->flags.
* If found, returns 0, res is overwritten, if not found, returns -1.
*/
-int find_next_system_ram(struct resource *res)
+static int find_next_system_ram(struct resource *res)
{
resource_size_t start, end;
struct resource *p;
@@ -267,6 +267,30 @@
res->end = p->end;
return 0;
}
+int
+walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
+ int (*func)(unsigned long, unsigned long, void *))
+{
+ struct resource res;
+ unsigned long pfn, len;
+ u64 orig_end;
+ int ret = -1;
+ res.start = (u64) start_pfn << PAGE_SHIFT;
+ res.end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1;
+ res.flags = IORESOURCE_MEM;
+ orig_end = res.end;
+ while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
+ pfn = (unsigned long)(res.start >> PAGE_SHIFT);
+ len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
+ ret = (*func)(pfn, len, arg);
+ if (ret)
+ break;
+ res.start = res.end + 1;
+ res.end = orig_end;
+ }
+ return ret;
+}
+
#endif
/*
