1 files changed, 43 insertions, 110 deletions

diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index b9f474c11393..dbec3a05590a 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -27,6 +27,24 @@
 
 #define MEMORY_CLASS_NAME	"memory"
 
+static const char *const online_type_to_str[] = {
+	[MMOP_OFFLINE] = "offline",
+	[MMOP_ONLINE] = "online",
+	[MMOP_ONLINE_KERNEL] = "online_kernel",
+	[MMOP_ONLINE_MOVABLE] = "online_movable",
+};
+
+int memhp_online_type_from_str(const char *str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(online_type_to_str); i++) {
+		if (sysfs_streq(str, online_type_to_str[i]))
+			return i;
+	}
+	return -EINVAL;
+}
+
 #define to_memory_block(dev) container_of(dev, struct memory_block, dev)
 
 static int sections_per_block;
@@ -97,30 +115,13 @@ static ssize_t phys_index_show(struct device *dev,
 }
 
 /*
- * Show whether the memory block is likely to be offlineable (or is already
- * offline). Once offline, the memory block could be removed. The return
- * value does, however, not indicate that there is a way to remove the
- * memory block.
+ * Legacy interface that we cannot remove. Always indicate "removable"
+ * with CONFIG_MEMORY_HOTREMOVE - bad heuristic.
  */
 static ssize_t removable_show(struct device *dev, struct device_attribute *attr,
 			      char *buf)
 {
-	struct memory_block *mem = to_memory_block(dev);
-	unsigned long pfn;
-	int ret = 1, i;
-
-	if (mem->state != MEM_ONLINE)
-		goto out;
-
-	for (i = 0; i < sections_per_block; i++) {
-		if (!present_section_nr(mem->start_section_nr + i))
-			continue;
-		pfn = section_nr_to_pfn(mem->start_section_nr + i);
-		ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
-	}
-
-out:
-	return sprintf(buf, "%d\n", ret);
+	return sprintf(buf, "%d\n", (int)IS_ENABLED(CONFIG_MEMORY_HOTREMOVE));
 }
 
 /*
@@ -162,45 +163,6 @@ int memory_notify(unsigned long val, void *v)
 }
 
 /*
- * The probe routines leave the pages uninitialized, just as the bootmem code
- * does. Make sure we do not access them, but instead use only information from
- * within sections.
- */
-static bool pages_correctly_probed(unsigned long start_pfn)
-{
-	unsigned long section_nr = pfn_to_section_nr(start_pfn);
-	unsigned long section_nr_end = section_nr + sections_per_block;
-	unsigned long pfn = start_pfn;
-
-	/*
-	 * memmap between sections is not contiguous except with
-	 * SPARSEMEM_VMEMMAP. We lookup the page once per section
-	 * and assume memmap is contiguous within each section
-	 */
-	for (; section_nr < section_nr_end; section_nr++) {
-		if (WARN_ON_ONCE(!pfn_valid(pfn)))
-			return false;
-
-		if (!present_section_nr(section_nr)) {
-			pr_warn("section %ld pfn[%lx, %lx) not present\n",
-				section_nr, pfn, pfn + PAGES_PER_SECTION);
-			return false;
-		} else if (!valid_section_nr(section_nr)) {
-			pr_warn("section %ld pfn[%lx, %lx) no valid memmap\n",
-				section_nr, pfn, pfn + PAGES_PER_SECTION);
-			return false;
-		} else if (online_section_nr(section_nr)) {
-			pr_warn("section %ld pfn[%lx, %lx) is already online\n",
-				section_nr, pfn, pfn + PAGES_PER_SECTION);
-			return false;
-		}
-		pfn += PAGES_PER_SECTION;
-	}
-
-	return true;
-}
-
-/*
  * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
  * OK to have direct references to sparsemem variables in here.
  */
@@ -216,9 +178,6 @@ memory_block_action(unsigned long start_section_nr, unsigned long action,
 
 	switch (action) {
 	case MEM_ONLINE:
-		if (!pages_correctly_probed(start_pfn))
-			return -EBUSY;
-
 		ret = online_pages(start_pfn, nr_pages, online_type, nid);
 		break;
 	case MEM_OFFLINE:
@@ -262,17 +221,14 @@ static int memory_subsys_online(struct device *dev)
 		return 0;
 
 	/*
-	 * If we are called from state_store(), online_type will be
-	 * set >= 0 Otherwise we were called from the device online
-	 * attribute and need to set the online_type.
+	 * When called via device_online() without configuring the online_type,
+	 * we want to default to MMOP_ONLINE.
 	 */
-	if (mem->online_type < 0)
-		mem->online_type = MMOP_ONLINE_KEEP;
+	if (mem->online_type == MMOP_OFFLINE)
+		mem->online_type = MMOP_ONLINE;
 
 	ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
-
-	/* clear online_type */
-	mem->online_type = -1;
+	mem->online_type = MMOP_OFFLINE;
 
 	return ret;
 }
@@ -284,40 +240,27 @@ static int memory_subsys_offline(struct device *dev)
 	if (mem->state == MEM_OFFLINE)
 		return 0;
 
-	/* Can't offline block with non-present sections */
-	if (mem->section_count != sections_per_block)
-		return -EINVAL;
-
 	return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
 }
 
 static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t count)
 {
+	const int online_type = memhp_online_type_from_str(buf);
 	struct memory_block *mem = to_memory_block(dev);
-	int ret, online_type;
+	int ret;
+
+	if (online_type < 0)
+		return -EINVAL;
 
 	ret = lock_device_hotplug_sysfs();
 	if (ret)
 		return ret;
 
-	if (sysfs_streq(buf, "online_kernel"))
-		online_type = MMOP_ONLINE_KERNEL;
-	else if (sysfs_streq(buf, "online_movable"))
-		online_type = MMOP_ONLINE_MOVABLE;
-	else if (sysfs_streq(buf, "online"))
-		online_type = MMOP_ONLINE_KEEP;
-	else if (sysfs_streq(buf, "offline"))
-		online_type = MMOP_OFFLINE;
-	else {
-		ret = -EINVAL;
-		goto err;
-	}
-
 	switch (online_type) {
 	case MMOP_ONLINE_KERNEL:
 	case MMOP_ONLINE_MOVABLE:
-	case MMOP_ONLINE_KEEP:
+	case MMOP_ONLINE:
 		/* mem->online_type is protected by device_hotplug_lock */
 		mem->online_type = online_type;
 		ret = device_online(&mem->dev);
@@ -329,7 +272,6 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr,
 		ret = -EINVAL; /* should never happen */
 	}
 
-err:
 	unlock_device_hotplug();
 
 	if (ret < 0)
@@ -397,7 +339,8 @@ static ssize_t valid_zones_show(struct device *dev,
 	}
 
 	nid = mem->nid;
-	default_zone = zone_for_pfn_range(MMOP_ONLINE_KEEP, nid, start_pfn, nr_pages);
+	default_zone = zone_for_pfn_range(MMOP_ONLINE, nid, start_pfn,
+					  nr_pages);
 	strcat(buf, default_zone->name);
 
 	print_allowed_zone(buf, nid, start_pfn, nr_pages, MMOP_ONLINE_KERNEL,
@@ -435,23 +378,20 @@ static DEVICE_ATTR_RO(block_size_bytes);
 static ssize_t auto_online_blocks_show(struct device *dev,
 				       struct device_attribute *attr, char *buf)
 {
-	if (memhp_auto_online)
-		return sprintf(buf, "online\n");
-	else
-		return sprintf(buf, "offline\n");
+	return sprintf(buf, "%s\n",
+		       online_type_to_str[memhp_default_online_type]);
 }
 
 static ssize_t auto_online_blocks_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t count)
 {
-	if (sysfs_streq(buf, "online"))
-		memhp_auto_online = true;
-	else if (sysfs_streq(buf, "offline"))
-		memhp_auto_online = false;
-	else
+	const int online_type = memhp_online_type_from_str(buf);
+
+	if (online_type < 0)
 		return -EINVAL;
 
+	memhp_default_online_type = online_type;
 	return count;
 }
 
@@ -644,7 +584,7 @@ static int init_memory_block(struct memory_block **memory,
 
 static int add_memory_block(unsigned long base_section_nr)
 {
-	int ret, section_count = 0;
+	int section_count = 0;
 	struct memory_block *mem;
 	unsigned long nr;
 
@@ -655,12 +595,8 @@ static int add_memory_block(unsigned long base_section_nr)
 
 	if (section_count == 0)
 		return 0;
-	ret = init_memory_block(&mem, base_memory_block_id(base_section_nr),
-				MEM_ONLINE);
-	if (ret)
-		return ret;
-	mem->section_count = section_count;
-	return 0;
+	return init_memory_block(&mem, base_memory_block_id(base_section_nr),
+				 MEM_ONLINE);
 }
 
 static void unregister_memory(struct memory_block *memory)
@@ -696,7 +632,6 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
 		ret = init_memory_block(&mem, block_id, MEM_OFFLINE);
 		if (ret)
 			break;
-		mem->section_count = sections_per_block;
 	}
 	if (ret) {
 		end_block_id = block_id;
@@ -705,7 +640,6 @@ int create_memory_block_devices(unsigned long start, unsigned long size)
 			mem = find_memory_block_by_id(block_id);
 			if (WARN_ON_ONCE(!mem))
 				continue;
-			mem->section_count = 0;
 			unregister_memory(mem);
 		}
 	}
@@ -734,7 +668,6 @@ void remove_memory_block_devices(unsigned long start, unsigned long size)
 		mem = find_memory_block_by_id(block_id);
 		if (WARN_ON_ONCE(!mem))
 			continue;
-		mem->section_count = 0;
 		unregister_memory_block_under_nodes(mem);
 		unregister_memory(mem);
 	}