[PATCH v2 5/6] mm/memory_hotplug: Move and simplify walk_memory_blocks()

David Hildenbrand
2019-06-20T10:36:10Z

Let's move walk_memory_blocks() to the place where memory block logic
resides and simplify it. While at it, add a type for the callback function.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Andrew Banman <andrew.banman@hpe.com>
Cc: "mike.travis@hpe.com" <mike.travis@hpe.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/base/memory.c | 42 ++++++++++++++++++++++++++
include/linux/memory.h | 3 ++
include/linux/memory_hotplug.h | 2 --
mm/memory_hotplug.c | 55 ----------------------------------
4 files changed, 45 insertions(+), 57 deletions(-)

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c54e80fd25a8..0204384b4d1d 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -44,6 +44,11 @@ static inline unsigned long pfn_to_block_id(unsigned long pfn)
return base_memory_block_id(pfn_to_section_nr(pfn));
}

+static inline unsigned long phys_to_block_id(unsigned long phys)
+{
+ return pfn_to_block_id(PFN_DOWN(phys));
+}
+
static int memory_subsys_online(struct device *dev);
static int memory_subsys_offline(struct device *dev);

@@ -851,3 +856,40 @@ int __init memory_dev_init(void)
printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
return ret;
}
+
+/**
+ * walk_memory_blocks - walk through all present memory blocks overlapped
+ * by the range [start, start + size)
+ *
+ * @start: start address of the memory range
+ * @size: size of the memory range
+ * @arg: argument passed to func
+ * @func: callback for each memory section walked
+ *
+ * This function walks through all present memory blocks overlapped by the
+ * range [start, start + size), calling func on each memory block.
+ *
+ * In case func() returns an error, walking is aborted and the error is
+ * returned.
+ */
+int walk_memory_blocks(unsigned long start, unsigned long size,
+ void *arg, walk_memory_blocks_func_t func)
+{
+ const unsigned long start_block_id = phys_to_block_id(start);
+ const unsigned long end_block_id = phys_to_block_id(start + size - 1);
+ struct memory_block *mem;
+ unsigned long block_id;
+ int ret = 0;
+
+ for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
+ mem = find_memory_block_by_id(block_id, NULL);
+ if (!mem)
+ continue;
+
+ ret = func(mem, arg);
+ put_device(&mem->dev);
+ if (ret)
+ break;
+ }
+ return ret;
+}
diff --git a/include/linux/memory.h b/include/linux/memory.h
index f26a5417ec5d..b3b388775a30 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -119,6 +119,9 @@ extern int memory_isolate_notify(unsigned long val, void *v);
extern struct memory_block *find_memory_block_hinted(struct mem_section *,
struct memory_block *);
extern struct memory_block *find_memory_block(struct mem_section *);
+typedef int (*walk_memory_blocks_func_t)(struct memory_block *, void *);
+extern int walk_memory_blocks(unsigned long start, unsigned long size,
+ void *arg, walk_memory_blocks_func_t func);
#define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index d9fffc34949f..475aff8efbf8 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -340,8 +340,6 @@ static inline void __remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */

extern void __ref free_area_init_core_hotplug(int nid);
-extern int walk_memory_blocks(unsigned long start, unsigned long size,
- void *arg, int (*func)(struct memory_block *, void *));
extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 122a7d31efdd..fc558e9ff939 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1661,62 +1661,7 @@ int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return __offline_pages(start_pfn, start_pfn + nr_pages);
}
-#endif /* CONFIG_MEMORY_HOTREMOVE */

-/**
- * walk_memory_blocks - walk through all present memory blocks overlapped
- * by the range [start, start + size)
- *
- * @start: start address of the memory range
- * @size: size of the memory range
- * @arg: argument passed to func
- * @func: callback for each memory block walked
- *
- * This function walks through all present memory blocks overlapped by the
- * range [start, start + size), calling func on each memory block.
- *
- * Returns the return value of func.
- */
-int walk_memory_blocks(unsigned long start, unsigned long size,
- void *arg, int (*func)(struct memory_block *, void *))
-{
- const unsigned long start_pfn = PFN_DOWN(start);
- const unsigned long end_pfn = PFN_UP(start + size - 1);
- struct memory_block *mem = NULL;
- struct mem_section *section;
- unsigned long pfn, section_nr;
- int ret;
-
- for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
- section_nr = pfn_to_section_nr(pfn);
- if (!present_section_nr(section_nr))
- continue;
-
- section = __nr_to_section(section_nr);
- /* same memblock? */
- if (mem)
- if ((section_nr >= mem->start_section_nr) &&
- (section_nr <= mem->end_section_nr))
- continue;
-
- mem = find_memory_block_hinted(section, mem);
- if (!mem)
- continue;
-
- ret = func(mem, arg);
- if (ret) {
- kobject_put(&mem->dev.kobj);
- return ret;
- }
- }
-
- if (mem)
- kobject_put(&mem->dev.kobj);
-
- return 0;
-}
-
-#ifdef CONFIG_MEMORY_HOTREMOVE
static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
{
int ret = !is_memblock_offlined(mem);
--
2.21.0