drivers/base/memory.c: get rid of find_memory_block_hinted()

No longer needed, let's remove it.  Also, drop the "hint" parameter
completely from "find_memory_block_by_id", as nobody needs it anymore.

[david@redhat.com: v3]
  Link: http://lkml.kernel.org/r/20190620183139.4352-7-david@redhat.com
[david@redhat.com: handle zero-length walks]
  Link: http://lkml.kernel.org/r/1c2edc22-afd7-2211-c4c7-40e54e5007e8@redhat.com
Link: http://lkml.kernel.org/r/20190614100114.311-7-david@redhat.comSigned-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Qian Cai <cai@lca.pw>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
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 <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: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/base/memory.c

@@ -588,30 +588,13 @@ int __weak arch_get_memory_phys_device(unsigned long start_pfn)
 	return 0;
 }
 
-/*
- * A reference for the returned object is held and the reference for the
- * hinted object is released.
- */
-static struct memory_block *find_memory_block_by_id(unsigned long block_id,
-						    struct memory_block *hint)
+/* A reference for the returned memory block device is acquired. */
+static struct memory_block *find_memory_block_by_id(unsigned long block_id)
 {
-	struct device *hintdev = hint ? &hint->dev : NULL;
 	struct device *dev;
 
-	dev = subsys_find_device_by_id(&memory_subsys, block_id, hintdev);
-	if (hint)
-		put_device(&hint->dev);
-	if (!dev)
-		return NULL;
-	return to_memory_block(dev);
-}
-
-struct memory_block *find_memory_block_hinted(struct mem_section *section,
-					      struct memory_block *hint)
-{
-	unsigned long block_id = base_memory_block_id(__section_nr(section));
-
-	return find_memory_block_by_id(block_id, hint);
+	dev = subsys_find_device_by_id(&memory_subsys, block_id, NULL);
+	return dev ? to_memory_block(dev) : NULL;
 }
 
 /*
@@ -624,7 +607,9 @@ struct memory_block *find_memory_block_hinted(struct mem_section *section,
  */
 struct memory_block *find_memory_block(struct mem_section *section)
 {
-	return find_memory_block_hinted(section, NULL);
+	unsigned long block_id = base_memory_block_id(__section_nr(section));
+
+	return find_memory_block_by_id(block_id);
 }
 
 static struct attribute *memory_memblk_attrs[] = {
@@ -675,7 +660,7 @@ static int init_memory_block(struct memory_block **memory,
 	unsigned long start_pfn;
 	int ret = 0;
 
-	mem = find_memory_block_by_id(block_id, NULL);
+	mem = find_memory_block_by_id(block_id);
 	if (mem) {
 		put_device(&mem->dev);
 		return -EEXIST;
@@ -755,7 +740,7 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
 		end_block_id = block_id;
 		for (block_id = start_block_id; block_id != end_block_id;
 		     block_id++) {
-			mem = find_memory_block_by_id(block_id, NULL);
+			mem = find_memory_block_by_id(block_id);
 			mem->section_count = 0;
 			unregister_memory(mem);
 		}
@@ -782,7 +767,7 @@ void remove_memory_block_devices(unsigned long start, unsigned long size)
 
 	mutex_lock(&mem_sysfs_mutex);
 	for (block_id = start_block_id; block_id != end_block_id; block_id++) {
-		mem = find_memory_block_by_id(block_id, NULL);
+		mem = find_memory_block_by_id(block_id);
 		if (WARN_ON_ONCE(!mem))
 			continue;
 		mem->section_count = 0;
@@ -881,8 +866,11 @@ int walk_memory_blocks(unsigned long start, unsigned long size,
 	unsigned long block_id;
 	int ret = 0;
 
+	if (!size)
+		return 0;
+
 	for (block_id = start_block_id; block_id <= end_block_id; block_id++) {
-		mem = find_memory_block_by_id(block_id, NULL);
+		mem = find_memory_block_by_id(block_id);
 		if (!mem)
 			continue;
 

include/linux/memory.h

@@ -116,8 +116,6 @@ void remove_memory_block_devices(unsigned long start, unsigned long size);
 extern int memory_dev_init(void);
 extern int memory_notify(unsigned long val, void *v);
 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,