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Subject[PATCH 5/8][mmotm] walk system ram range
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Originally, walk_memory_resource() was introduced to traverse all memory
of "System RAM" for detecting memory hotplug/unplug range. For doing so,
flags of IORESOUCE_MEM|IORESOURCE_BUSY was used and this was enough for
memory hotplug.

But for using other purpose, /proc/kcore, this may includes some firmware
area marked as IORESOURCE_BUSY | IORESOUCE_MEM. This patch makes the
check strict to find out busy "System RAM".

Note: PPC64 keeps their own walk_memory_resouce(), which walk through
ppc64's lmb informaton. Because old kclist_add() is called per lmb, this
patch makes no difference in behavior, finally.

And this patch removes CONFIG_MEMORY_HOTPLUG check from this function.
Because pfn_valid() just show "there is memmap or not* and cannot be used
for "there is physical memory or not", this function is useful in generic
to scan physical memory range.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

arch/powerpc/mm/mem.c | 4 ++--
drivers/net/ehea/ehea_qmr.c | 2 +-
include/linux/ioport.h | 4 ++++
include/linux/memory_hotplug.h | 8 --------
kernel/resource.c | 23 ++++++++++++++++-------
mm/memory_hotplug.c | 6 +++---
6 files changed, 26 insertions(+), 21 deletions(-)

Index: mmotm-2.6.31-Aug27/arch/powerpc/mm/mem.c
===================================================================
--- mmotm-2.6.31-Aug27.orig/arch/powerpc/mm/mem.c
+++ mmotm-2.6.31-Aug27/arch/powerpc/mm/mem.c
@@ -143,8 +143,8 @@ int arch_add_memory(int nid, u64 start,
* memory regions, find holes and callback for contiguous regions.
*/
int
-walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
- int (*func)(unsigned long, unsigned long, void *))
+walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
+ void *arg, int (*func)(unsigned long, unsigned long, void *))
{
struct lmb_property res;
unsigned long pfn, len;
Index: mmotm-2.6.31-Aug27/drivers/net/ehea/ehea_qmr.c
===================================================================
--- mmotm-2.6.31-Aug27.orig/drivers/net/ehea/ehea_qmr.c
+++ mmotm-2.6.31-Aug27/drivers/net/ehea/ehea_qmr.c
@@ -751,7 +751,7 @@ int ehea_create_busmap(void)

mutex_lock(&ehea_busmap_mutex);
ehea_mr_len = 0;
- ret = walk_memory_resource(0, 1ULL << MAX_PHYSMEM_BITS, NULL,
+ ret = walk_system_ram_range(0, 1ULL << MAX_PHYSMEM_BITS, NULL,
ehea_create_busmap_callback);
mutex_unlock(&ehea_busmap_mutex);
return ret;
Index: mmotm-2.6.31-Aug27/include/linux/ioport.h
===================================================================
--- mmotm-2.6.31-Aug27.orig/include/linux/ioport.h
+++ mmotm-2.6.31-Aug27/include/linux/ioport.h
@@ -184,5 +184,9 @@ extern void __devm_release_region(struct
extern int iomem_map_sanity_check(resource_size_t addr, unsigned long size);
extern int iomem_is_exclusive(u64 addr);

+extern int
+walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
+ void *arg, int (*func)(unsigned long, unsigned long, void *));
+
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_IOPORT_H */
Index: mmotm-2.6.31-Aug27/include/linux/memory_hotplug.h
===================================================================
--- mmotm-2.6.31-Aug27.orig/include/linux/memory_hotplug.h
+++ mmotm-2.6.31-Aug27/include/linux/memory_hotplug.h
@@ -191,14 +191,6 @@ static inline void register_page_bootmem

#endif /* ! CONFIG_MEMORY_HOTPLUG */

-/*
- * Walk through all memory which is registered as resource.
- * arg is (start_pfn, nr_pages, private_arg_pointer)
- */
-extern int walk_memory_resource(unsigned long start_pfn,
- unsigned long nr_pages, void *arg,
- int (*func)(unsigned long, unsigned long, void *));
-
#ifdef CONFIG_MEMORY_HOTREMOVE

extern int is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
Index: mmotm-2.6.31-Aug27/kernel/resource.c
===================================================================
--- mmotm-2.6.31-Aug27.orig/kernel/resource.c
+++ mmotm-2.6.31-Aug27/kernel/resource.c
@@ -233,13 +233,13 @@ int release_resource(struct resource *ol

EXPORT_SYMBOL(release_resource);

-#if defined(CONFIG_MEMORY_HOTPLUG) && !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
+#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
* Finds the lowest memory reosurce exists within [res->start.res->end)
- * the caller must specify res->start, res->end, res->flags.
+ * the caller must specify res->start, res->end, res->flags and "name".
* If found, returns 0, res is overwritten, if not found, returns -1.
*/
-static int find_next_system_ram(struct resource *res)
+static int find_next_system_ram(struct resource *res, char *name)
{
resource_size_t start, end;
struct resource *p;
@@ -255,6 +255,8 @@ static int find_next_system_ram(struct r
/* system ram is just marked as IORESOURCE_MEM */
if (p->flags != res->flags)
continue;
+ if (name && strcmp(p->name, name))
+ continue;
if (p->start > end) {
p = NULL;
break;
@@ -272,19 +274,26 @@ static int find_next_system_ram(struct r
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 *))
+
+/*
+ * This function calls callback against all memory range of "System RAM"
+ * which are marked as IORESOURCE_MEM and IORESOUCE_BUSY.
+ * Now, this function is only for "System RAM".
+ */
+int walk_system_ram_range(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 | IORESOURCE_BUSY;
orig_end = res.end;
- while ((res.start < res.end) && (find_next_system_ram(&res) >= 0)) {
+ while ((res.start < res.end) &&
+ (find_next_system_ram(&res, "System RAM") >= 0)) {
pfn = (unsigned long)(res.start >> PAGE_SHIFT);
len = (unsigned long)((res.end + 1 - res.start) >> PAGE_SHIFT);
ret = (*func)(pfn, len, arg);
Index: mmotm-2.6.31-Aug27/mm/memory_hotplug.c
===================================================================
--- mmotm-2.6.31-Aug27.orig/mm/memory_hotplug.c
+++ mmotm-2.6.31-Aug27/mm/memory_hotplug.c
@@ -413,7 +413,7 @@ int online_pages(unsigned long pfn, unsi
if (!populated_zone(zone))
need_zonelists_rebuild = 1;

- ret = walk_memory_resource(pfn, nr_pages, &onlined_pages,
+ ret = walk_system_ram_range(pfn, nr_pages, &onlined_pages,
online_pages_range);
if (ret) {
printk(KERN_DEBUG "online_pages %lx at %lx failed\n",
@@ -705,7 +705,7 @@ offline_isolated_pages_cb(unsigned long
static void
offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
{
- walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
+ walk_system_ram_range(start_pfn, end_pfn - start_pfn, NULL,
offline_isolated_pages_cb);
}

@@ -731,7 +731,7 @@ check_pages_isolated(unsigned long start
long offlined = 0;
int ret;

- ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
+ ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &offlined,
check_pages_isolated_cb);
if (ret < 0)
offlined = (long)ret;


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