mm/memory_hotplug.c: make register_mem_sect_under_node() a callback of walk_memory_range()

link_mem_sections() and walk_memory_range() share most of the code, so
we can use convert link_mem_sections() into a dummy function that calls
walk_memory_range() with a callback to register_mem_sect_under_node().

This patch converts register_mem_sect_under_node() in order to match a
walk_memory_range's callback, getting rid of the check_nid argument and
checking instead if the system is still boothing, since we only have to
check for the nid if the system is in such state.

Link: http://lkml.kernel.org/r/20180622111839.10071-4-osalvador@techadventures.net
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Suggested-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Tested-by: Reza Arbab <arbab@linux.vnet.ibm.com>
Tested-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 14 insertions, 47 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index a5e821d09656..845d5523812b 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -399,10 +399,9 @@ static int __ref get_nid_for_pfn(unsigned long pfn)
 }
 
 /* register memory section under specified node if it spans that node */
-int register_mem_sect_under_node(struct memory_block *mem_blk, int nid,
-                                 bool check_nid)
+int register_mem_sect_under_node(struct memory_block *mem_blk, void *arg)
 {
-        int ret;
+        int ret, nid = *(int *)arg;
         unsigned long pfn, sect_start_pfn, sect_end_pfn;
 
         if (!mem_blk)
@@ -433,7 +432,7 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid,
                  * case, during hotplug we know that all pages in the memory
                  * block belong to the same node.
                  */
-                if (check_nid) {
+                if (system_state == SYSTEM_BOOTING) {
                         page_nid = get_nid_for_pfn(pfn);
                         if (page_nid < 0)
                                 continue;
@@ -490,41 +489,10 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
         return 0;
 }
 
-int link_mem_sections(int nid, unsigned long start_pfn, unsigned long nr_pages,
-                      bool check_nid)
+int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn)
 {
-        unsigned long end_pfn = start_pfn + nr_pages;
-        unsigned long pfn;
-        struct memory_block *mem_blk = NULL;
-        int err = 0;
-
-        for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
-                unsigned long section_nr = pfn_to_section_nr(pfn);
-                struct mem_section *mem_sect;
-                int ret;
-
-                if (!present_section_nr(section_nr))
-                        continue;
-                mem_sect = __nr_to_section(section_nr);
-
-                /* same memblock ? */
-                if (mem_blk)
-                        if ((section_nr >= mem_blk->start_section_nr) &&
-                            (section_nr <= mem_blk->end_section_nr))
-                                continue;
-
-                mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
-
-                ret = register_mem_sect_under_node(mem_blk, nid, check_nid);
-                if (!err)
-                        err = ret;
-
-                /* discard ref obtained in find_memory_block() */
-        }
-
-        if (mem_blk)
-                kobject_put(&mem_blk->dev.kobj);
-        return err;
+        return walk_memory_range(start_pfn, end_pfn, (void *)&nid,
+                                        register_mem_sect_under_node);
 }
 
 #ifdef CONFIG_HUGETLBFS
diff --git a/include/linux/node.h b/include/linux/node.h
index 6d336e38d155..257bb3d6d014 100644
--- a/include/linux/node.h
+++ b/include/linux/node.h
@@ -33,10 +33,10 @@ typedef  void (*node_registration_func_t)(struct node *);
 
 #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_NUMA)
 extern int link_mem_sections(int nid, unsigned long start_pfn,
-                             unsigned long nr_pages, bool check_nid);
+                             unsigned long end_pfn);
 #else
 static inline int link_mem_sections(int nid, unsigned long start_pfn,
-                                    unsigned long nr_pages, bool check_nid)
+                                    unsigned long end_pfn)
 {
         return 0;
 }
@@ -54,12 +54,14 @@ static inline int register_one_node(int nid)
 
         if (node_online(nid)) {
                 struct pglist_data *pgdat = NODE_DATA(nid);
+                unsigned long start_pfn = pgdat->node_start_pfn;
+                unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
 
                 error = __register_one_node(nid);
                 if (error)
                         return error;
                 /* link memory sections under this node */
-                error = link_mem_sections(nid, pgdat->node_start_pfn, pgdat->node_spanned_pages, true);
+                error = link_mem_sections(nid, start_pfn, end_pfn);
         }
 
         return error;
@@ -69,7 +71,7 @@ extern void unregister_one_node(int nid);
 extern int register_cpu_under_node(unsigned int cpu, unsigned int nid);
 extern int unregister_cpu_under_node(unsigned int cpu, unsigned int nid);
 extern int register_mem_sect_under_node(struct memory_block *mem_blk,
-                                                int nid, bool check_nid);
+                                                void *arg);
 extern int unregister_mem_sect_under_nodes(struct memory_block *mem_blk,
                                            unsigned long phys_index);
 
@@ -99,7 +101,7 @@ static inline int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
         return 0;
 }
 static inline int register_mem_sect_under_node(struct memory_block *mem_blk,
-                                                        int nid, bool check_nid)
+                                                        void *arg)
 {
         return 0;
 }
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e2ed64b994e5..4eb6e824a80c 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1123,7 +1123,6 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
         u64 start, size;
         bool new_node = false;
         int ret;
-        unsigned long start_pfn, nr_pages;
 
         start = res->start;
         size = resource_size(res);
@@ -1164,9 +1163,7 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
         }
 
         /* link memory sections under this node.*/
-        start_pfn = start >> PAGE_SHIFT;
-        nr_pages = size >> PAGE_SHIFT;
-        ret = link_mem_sections(nid, start_pfn, nr_pages, false);
+        ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1));
         BUG_ON(ret);
 
         /* create new memmap entry */