memory-hotplug: remove /sys/firmware/memmap/X sysfs

When (hot)adding memory into system, /sys/firmware/memmap/X/{end, start,
type} sysfs files are created.  But there is no code to remove these
files.  The patch implements the function to remove them.

The code does not free firmware_map_entry which is allocated by bootmem,
which is a slight memory leak.  But that memory is reused when the sysfs
file is recreated, so the leak is bounded.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
Reviewed-by: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Jiang Liu <jiang.liu@huawei.com>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index 90723e65b08172ac49e67d01065aa79ca7f7ee54..4211da59cc10c1d99a79956b3ce268ac9693c1f3 100644 (file)
--- a/drivers/firmware/memmap.c
+++ b/drivers/firmware/memmap.c
@@ -21,6 +21,7 @@
 #include <linux/types.h>
 #include <linux/bootmem.h>
 #include <linux/slab.h>
+#include <linux/mm.h>
 
 /*
  * Data types ------------------------------------------------------------------
@@ -79,7 +80,26 @@ static const struct sysfs_ops memmap_attr_ops = {
        .show = memmap_attr_show,
 };
 
+
+static inline struct firmware_map_entry *
+to_memmap_entry(struct kobject *kobj)
+{
+       return container_of(kobj, struct firmware_map_entry, kobj);
+}
+
+static void release_firmware_map_entry(struct kobject *kobj)
+{
+       struct firmware_map_entry *entry = to_memmap_entry(kobj);
+
+       if (PageReserved(virt_to_page(entry)))
+               /* There is no way to free memory allocated from bootmem */
+               return;
+
+       kfree(entry);
+}
+
 static struct kobj_type memmap_ktype = {
+       .release        = release_firmware_map_entry,
        .sysfs_ops      = &memmap_attr_ops,
        .default_attrs  = def_attrs,
 };
@@ -94,6 +114,7 @@ static struct kobj_type memmap_ktype = {
  * in firmware initialisation code in one single thread of execution.
  */
 static LIST_HEAD(map_entries);
+static DEFINE_SPINLOCK(map_entries_lock);
 
 /**
  * firmware_map_add_entry() - Does the real work to add a firmware memmap entry.
@@ -118,11 +139,25 @@ static int firmware_map_add_entry(u64 start, u64 end,
        INIT_LIST_HEAD(&entry->list);
        kobject_init(&entry->kobj, &memmap_ktype);
 
+       spin_lock(&map_entries_lock);
        list_add_tail(&entry->list, &map_entries);
+       spin_unlock(&map_entries_lock);
 
        return 0;
 }
 
+/**
+ * firmware_map_remove_entry() - Does the real work to remove a firmware
+ * memmap entry.
+ * @entry: removed entry.
+ **/
+static inline void firmware_map_remove_entry(struct firmware_map_entry *entry)
+{
+       spin_lock(&map_entries_lock);
+       list_del(&entry->list);
+       spin_unlock(&map_entries_lock);
+}
+
 /*
  * Add memmap entry on sysfs
  */
@@ -144,6 +179,35 @@ static int add_sysfs_fw_map_entry(struct firmware_map_entry *entry)
        return 0;
 }
 
+/*
+ * Remove memmap entry on sysfs
+ */
+static inline void remove_sysfs_fw_map_entry(struct firmware_map_entry *entry)
+{
+       kobject_put(&entry->kobj);
+}
+
+/*
+ * Search memmap entry
+ */
+
+static struct firmware_map_entry * __meminit
+firmware_map_find_entry(u64 start, u64 end, const char *type)
+{
+       struct firmware_map_entry *entry;
+
+       spin_lock(&map_entries_lock);
+       list_for_each_entry(entry, &map_entries, list)
+               if ((entry->start == start) && (entry->end == end) &&
+                   (!strcmp(entry->type, type))) {
+                       spin_unlock(&map_entries_lock);
+                       return entry;
+               }
+
+       spin_unlock(&map_entries_lock);
+       return NULL;
+}
+
 /**
  * firmware_map_add_hotplug() - Adds a firmware mapping entry when we do
  * memory hotplug.
@@ -196,6 +260,32 @@ int __init firmware_map_add_early(u64 start, u64 end, const char *type)
        return firmware_map_add_entry(start, end, type, entry);
 }
 
+/**
+ * firmware_map_remove() - remove a firmware mapping entry
+ * @start: Start of the memory range.
+ * @end:   End of the memory range.
+ * @type:  Type of the memory range.
+ *
+ * removes a firmware mapping entry.
+ *
+ * Returns 0 on success, or -EINVAL if no entry.
+ **/
+int __meminit firmware_map_remove(u64 start, u64 end, const char *type)
+{
+       struct firmware_map_entry *entry;
+
+       entry = firmware_map_find_entry(start, end - 1, type);
+       if (!entry)
+               return -EINVAL;
+
+       firmware_map_remove_entry(entry);
+
+       /* remove the memmap entry */
+       remove_sysfs_fw_map_entry(entry);
+
+       return 0;
+}
+
 /*
  * Sysfs functions -------------------------------------------------------------
  */
@@ -217,8 +307,10 @@ static ssize_t type_show(struct firmware_map_entry *entry, char *buf)
        return snprintf(buf, PAGE_SIZE, "%s\n", entry->type);
 }
 
-#define to_memmap_attr(_attr) container_of(_attr, struct memmap_attribute, attr)
-#define to_memmap_entry(obj) container_of(obj, struct firmware_map_entry, kobj)
+static inline struct memmap_attribute *to_memmap_attr(struct attribute *attr)
+{
+       return container_of(attr, struct memmap_attribute, attr);
+}
 
 static ssize_t memmap_attr_show(struct kobject *kobj,
                                struct attribute *attr, char *buf)

diff --git a/include/linux/firmware-map.h b/include/linux/firmware-map.h
index 43fe52fcef0f60973cb61c33a30e0cbb00450811..71d4fa721db946203536908b5e189ef19e13787e 100644 (file)
--- a/include/linux/firmware-map.h
+++ b/include/linux/firmware-map.h
@@ -25,6 +25,7 @@
 
 int firmware_map_add_early(u64 start, u64 end, const char *type);
 int firmware_map_add_hotplug(u64 start, u64 end, const char *type);
+int firmware_map_remove(u64 start, u64 end, const char *type);
 
 #else /* CONFIG_FIRMWARE_MEMMAP */
 
@@ -38,6 +39,11 @@ static inline int firmware_map_add_hotplug(u64 start, u64 end, const char *type)
        return 0;
 }
 
+static inline int firmware_map_remove(u64 start, u64 end, const char *type)
+{
+       return 0;
+}
+
 #endif /* CONFIG_FIRMWARE_MEMMAP */
 
 #endif /* _LINUX_FIRMWARE_MAP_H */

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e5b91b12cec3bffb67cb655eb4f52b345be70457..a776dbf3fa0093dbe39b9c15aea51501c5216a03 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1460,7 +1460,7 @@ static int is_memblock_offlined_cb(struct memory_block *mem, void *arg)
        return ret;
 }
 
-int remove_memory(u64 start, u64 size)
+int __ref remove_memory(u64 start, u64 size)
 {
        unsigned long start_pfn, end_pfn;
        int ret = 0;
@@ -1510,6 +1510,9 @@ repeat:
                return ret;
        }
 
+       /* remove memmap entry */
+       firmware_map_remove(start, start + size, "System RAM");
+
        unlock_memory_hotplug();
 
        return 0;