2 files changed, 139 insertions, 63 deletions

diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt
index 57e7e9cc1870..8f485d72cf25 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -126,36 +126,51 @@ config options.
 --------------------------------
 4 sysfs files for memory hotplug
 --------------------------------
-All sections have their device information under /sys/devices/system/memory as
+All sections have their device information in sysfs.  Each section is part of
+a memory block under /sys/devices/system/memory as
 
 /sys/devices/system/memory/memoryXXX
-(XXX is section id.)
+(XXX is the section id.)
 
-Now, XXX is defined as start_address_of_section / section_size.
+Now, XXX is defined as (start_address_of_section / section_size) of the first
+section contained in the memory block.  The files 'phys_index' and
+'end_phys_index' under each directory report the beginning and end section id's
+for the memory block covered by the sysfs directory.  It is expected that all
+memory sections in this range are present and no memory holes exist in the
+range. Currently there is no way to determine if there is a memory hole, but
+the existence of one should not affect the hotplug capabilities of the memory
+block.
 
 For example, assume 1GiB section size. A device for a memory starting at
 0x100000000 is /sys/device/system/memory/memory4
 (0x100000000 / 1Gib = 4)
 This device covers address range [0x100000000 ... 0x140000000)
 
-Under each section, you can see 4 files.
+Under each section, you can see 4 or 5 files, the end_phys_index file being
+a recent addition and not present on older kernels.
 
-/sys/devices/system/memory/memoryXXX/phys_index
+/sys/devices/system/memory/memoryXXX/start_phys_index
+/sys/devices/system/memory/memoryXXX/end_phys_index
 /sys/devices/system/memory/memoryXXX/phys_device
 /sys/devices/system/memory/memoryXXX/state
 /sys/devices/system/memory/memoryXXX/removable
 
-'phys_index' : read-only and contains section id, same as XXX.
-'state'      : read-write
-               at read:  contains online/offline state of memory.
-               at write: user can specify "online", "offline" command
-'phys_device': read-only: designed to show the name of physical memory device.
-               This is not well implemented now.
-'removable'  : read-only: contains an integer value indicating
-               whether the memory section is removable or not
-               removable.  A value of 1 indicates that the memory
-               section is removable and a value of 0 indicates that
-               it is not removable.
+'phys_index'      : read-only and contains section id of the first section
+                    in the memory block, same as XXX.
+'end_phys_index'  : read-only and contains section id of the last section
+                    in the memory block.
+'state'           : read-write
+                    at read:  contains online/offline state of memory.
+                    at write: user can specify "online", "offline" command
+                    which will be performed on al sections in the block.
+'phys_device'     : read-only: designed to show the name of physical memory
+                    device.  This is not well implemented now.
+'removable'       : read-only: contains an integer value indicating
+                    whether the memory block is removable or not
+                    removable.  A value of 1 indicates that the memory
+                    block is removable and a value of 0 indicates that
+                    it is not removable. A memory block is removable only if
+                    every section in the block is removable.
 
 NOTE:
   These directories/files appear after physical memory hotplug phase.
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index cafeaaf0428f..0b7040042587 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -30,6 +30,14 @@
 static DEFINE_MUTEX(mem_sysfs_mutex);
 
 #define MEMORY_CLASS_NAME       "memory"
+#define MIN_MEMORY_BLOCK_SIZE   (1 << SECTION_SIZE_BITS)
+
+static int sections_per_block;
+
+static inline int base_memory_block_id(int section_nr)
+{
+        return section_nr / sections_per_block;
+}
 
 static struct sysdev_class memory_sysdev_class = {
         .name = MEMORY_CLASS_NAME,
@@ -84,28 +92,47 @@ EXPORT_SYMBOL(unregister_memory_isolate_notifier);
  * register_memory - Setup a sysfs device for a memory block
  */
 static
-int register_memory(struct memory_block *memory, struct mem_section *section)
+int register_memory(struct memory_block *memory)
 {
         int error;
 
         memory->sysdev.cls = &memory_sysdev_class;
-        memory->sysdev.id = __section_nr(section);
+        memory->sysdev.id = memory->phys_index / sections_per_block;
 
         error = sysdev_register(&memory->sysdev);
         return error;
 }
 
 static void
-unregister_memory(struct memory_block *memory, struct mem_section *section)
+unregister_memory(struct memory_block *memory)
 {
         BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
-        BUG_ON(memory->sysdev.id != __section_nr(section));
 
         /* drop the ref. we got in remove_memory_block() */
         kobject_put(&memory->sysdev.kobj);
         sysdev_unregister(&memory->sysdev);
 }
 
+unsigned long __weak memory_block_size_bytes(void)
+{
+        return MIN_MEMORY_BLOCK_SIZE;
+}
+
+static unsigned long get_memory_block_size(void)
+{
+        unsigned long block_sz;
+
+        block_sz = memory_block_size_bytes();
+
+        /* Validate blk_sz is a power of 2 and not less than section size */
+        if ((block_sz & (block_sz - 1)) || (block_sz < MIN_MEMORY_BLOCK_SIZE)) {
+                WARN_ON(1);
+                block_sz = MIN_MEMORY_BLOCK_SIZE;
+        }
+
+        return block_sz;
+}
+
 /*
  * use this as the physical section index that this memsection
  * uses.
@@ -116,7 +143,7 @@ static ssize_t show_mem_phys_index(struct sys_device *dev,
 {
         struct memory_block *mem =
                 container_of(dev, struct memory_block, sysdev);
-        return sprintf(buf, "%08lx\n", mem->phys_index);
+        return sprintf(buf, "%08lx\n", mem->phys_index / sections_per_block);
 }
 
 /*
@@ -125,13 +152,16 @@ static ssize_t show_mem_phys_index(struct sys_device *dev,
 static ssize_t show_mem_removable(struct sys_device *dev,
                         struct sysdev_attribute *attr, char *buf)
 {
-        unsigned long start_pfn;
-        int ret;
+        unsigned long i, pfn;
+        int ret = 1;
         struct memory_block *mem =
                 container_of(dev, struct memory_block, sysdev);
 
-        start_pfn = section_nr_to_pfn(mem->phys_index);
-        ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
+        for (i = 0; i < sections_per_block; i++) {
+                pfn = section_nr_to_pfn(mem->phys_index + i);
+                ret &= is_mem_section_removable(pfn, PAGES_PER_SECTION);
+        }
+
         return sprintf(buf, "%d\n", ret);
 }
 
@@ -184,17 +214,14 @@ int memory_isolate_notify(unsigned long val, void *v)
  * OK to have direct references to sparsemem variables in here.
  */
 static int
-memory_block_action(struct memory_block *mem, unsigned long action)
+memory_section_action(unsigned long phys_index, unsigned long action)
 {
         int i;
-        unsigned long psection;
         unsigned long start_pfn, start_paddr;
         struct page *first_page;
         int ret;
-        int old_state = mem->state;
 
-        psection = mem->phys_index;
-        first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
+        first_page = pfn_to_page(phys_index << PFN_SECTION_SHIFT);
 
         /*
          * The probe routines leave the pages reserved, just
@@ -207,8 +234,8 @@ memory_block_action(struct memory_block *mem, unsigned long action)
                                 continue;
 
                         printk(KERN_WARNING "section number %ld page number %d "
-                                "not reserved, was it already online? \n",
-                                psection, i);
+                                "not reserved, was it already online?\n",
+                                phys_index, i);
                         return -EBUSY;
                 }
         }
@@ -219,18 +246,13 @@ memory_block_action(struct memory_block *mem, unsigned long action)
                         ret = online_pages(start_pfn, PAGES_PER_SECTION);
                         break;
                 case MEM_OFFLINE:
-                        mem->state = MEM_GOING_OFFLINE;
                         start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
                         ret = remove_memory(start_paddr,
                                             PAGES_PER_SECTION << PAGE_SHIFT);
-                        if (ret) {
-                                mem->state = old_state;
-                                break;
-                        }
                         break;
                 default:
-                        WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
-                                        __func__, mem, action, action);
+                        WARN(1, KERN_WARNING "%s(%ld, %ld) unknown action: "
+                             "%ld\n", __func__, phys_index, action, action);
                         ret = -EINVAL;
         }
 
@@ -240,7 +262,8 @@ memory_block_action(struct memory_block *mem, unsigned long action)
 static int memory_block_change_state(struct memory_block *mem,
                 unsigned long to_state, unsigned long from_state_req)
 {
-        int ret = 0;
+        int i, ret = 0;
+
         mutex_lock(&mem->state_mutex);
 
         if (mem->state != from_state_req) {
@@ -248,8 +271,22 @@ static int memory_block_change_state(struct memory_block *mem,
                 goto out;
         }
 
-        ret = memory_block_action(mem, to_state);
-        if (!ret)
+        if (to_state == MEM_OFFLINE)
+                mem->state = MEM_GOING_OFFLINE;
+
+        for (i = 0; i < sections_per_block; i++) {
+                ret = memory_section_action(mem->phys_index + i, to_state);
+                if (ret)
+                        break;
+        }
+
+        if (ret) {
+                for (i = 0; i < sections_per_block; i++)
+                        memory_section_action(mem->phys_index + i,
+                                              from_state_req);
+
+                mem->state = from_state_req;
+        } else
                 mem->state = to_state;
 
 out:
@@ -262,20 +299,15 @@ store_mem_state(struct sys_device *dev,
                 struct sysdev_attribute *attr, const char *buf, size_t count)
 {
         struct memory_block *mem;
-        unsigned int phys_section_nr;
         int ret = -EINVAL;
 
         mem = container_of(dev, struct memory_block, sysdev);
-        phys_section_nr = mem->phys_index;
-
-        if (!present_section_nr(phys_section_nr))
-                goto out;
 
         if (!strncmp(buf, "online", min((int)count, 6)))
                 ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
         else if(!strncmp(buf, "offline", min((int)count, 7)))
                 ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
-out:
+
         if (ret)
                 return ret;
         return count;
@@ -315,7 +347,7 @@ static ssize_t
 print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,
                  char *buf)
 {
-        return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
+        return sprintf(buf, "%lx\n", get_memory_block_size());
 }
 
 static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
@@ -444,6 +476,7 @@ struct memory_block *find_memory_block_hinted(struct mem_section *section,
         struct sys_device *sysdev;
         struct memory_block *mem;
         char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
+        int block_id = base_memory_block_id(__section_nr(section));
 
         kobj = hint ? &hint->sysdev.kobj : NULL;
 
@@ -451,7 +484,7 @@ struct memory_block *find_memory_block_hinted(struct mem_section *section,
          * This only works because we know that section == sysdev->id
          * slightly redundant with sysdev_register()
          */
-        sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
+        sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, block_id);
 
         kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
         if (!kobj)
@@ -476,26 +509,27 @@ struct memory_block *find_memory_block(struct mem_section *section)
         return find_memory_block_hinted(section, NULL);
 }
 
-static int add_memory_block(int nid, struct mem_section *section,
-                        unsigned long state, enum mem_add_context context)
+static int init_memory_block(struct memory_block **memory,
+                             struct mem_section *section, unsigned long state)
 {
-        struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);
+        struct memory_block *mem;
         unsigned long start_pfn;
+        int scn_nr;
         int ret = 0;
 
+        mem = kzalloc(sizeof(*mem), GFP_KERNEL);
         if (!mem)
                 return -ENOMEM;
 
-        mutex_lock(&mem_sysfs_mutex);
-
-        mem->phys_index = __section_nr(section);
+        scn_nr = __section_nr(section);
+        mem->phys_index = base_memory_block_id(scn_nr) * sections_per_block;
         mem->state = state;
         mem->section_count++;
         mutex_init(&mem->state_mutex);
         start_pfn = section_nr_to_pfn(mem->phys_index);
         mem->phys_device = arch_get_memory_phys_device(start_pfn);
 
-        ret = register_memory(mem, section);
+        ret = register_memory(mem);
         if (!ret)
                 ret = mem_create_simple_file(mem, phys_index);
         if (!ret)
@@ -504,8 +538,29 @@ static int add_memory_block(int nid, struct mem_section *section,
                 ret = mem_create_simple_file(mem, phys_device);
         if (!ret)
                 ret = mem_create_simple_file(mem, removable);
+
+        *memory = mem;
+        return ret;
+}
+
+static int add_memory_section(int nid, struct mem_section *section,
+                        unsigned long state, enum mem_add_context context)
+{
+        struct memory_block *mem;
+        int ret = 0;
+
+        mutex_lock(&mem_sysfs_mutex);
+
+        mem = find_memory_block(section);
+        if (mem) {
+                mem->section_count++;
+                kobject_put(&mem->sysdev.kobj);
+        } else
+                ret = init_memory_block(&mem, section, state);
+
         if (!ret) {
-                if (context == HOTPLUG)
+                if (context == HOTPLUG &&
+                    mem->section_count == sections_per_block)
                         ret = register_mem_sect_under_node(mem, nid);
         }
 
@@ -528,8 +583,10 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
                 mem_remove_simple_file(mem, state);
                 mem_remove_simple_file(mem, phys_device);
                 mem_remove_simple_file(mem, removable);
-                unregister_memory(mem, section);
-        }
+                unregister_memory(mem);
+                kfree(mem);
+        } else
+                kobject_put(&mem->sysdev.kobj);
 
         mutex_unlock(&mem_sysfs_mutex);
         return 0;
@@ -541,7 +598,7 @@ int remove_memory_block(unsigned long node_id, struct mem_section *section,
  */
 int register_new_memory(int nid, struct mem_section *section)
 {
-        return add_memory_block(nid, section, MEM_OFFLINE, HOTPLUG);
+        return add_memory_section(nid, section, MEM_OFFLINE, HOTPLUG);
 }
 
 int unregister_memory_section(struct mem_section *section)
@@ -560,12 +617,16 @@ int __init memory_dev_init(void)
         unsigned int i;
         int ret;
         int err;
+        unsigned long block_sz;
 
         memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
         ret = sysdev_class_register(&memory_sysdev_class);
         if (ret)
                 goto out;
 
+        block_sz = get_memory_block_size();
+        sections_per_block = block_sz / MIN_MEMORY_BLOCK_SIZE;
+
         /*
          * Create entries for memory sections that were found
          * during boot and have been initialized
@@ -573,8 +634,8 @@ int __init memory_dev_init(void)
         for (i = 0; i < NR_MEM_SECTIONS; i++) {
                 if (!present_section_nr(i))
                         continue;
-                err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE,
-                                       BOOT);
+                err = add_memory_section(0, __nr_to_section(i), MEM_ONLINE,
+                                         BOOT);
                 if (!ret)
                         ret = err;
         }