[RFC v9 PATCH 08/21] memory-hotplug: remove /sys/firmware/memmap/X sysfs
wency at cn.fujitsu.com
wency at cn.fujitsu.com
Wed Sep 5 19:25:42 EST 2012
From: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
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.
Note : The code does not free firmware_map_entry since there is no way to free
memory which is allocated by bootmem.
CC: David Rientjes <rientjes at google.com>
CC: Jiang Liu <liuj97 at gmail.com>
CC: Len Brown <len.brown at intel.com>
CC: Benjamin Herrenschmidt <benh at kernel.crashing.org>
CC: Paul Mackerras <paulus at samba.org>
CC: Christoph Lameter <cl at linux.com>
Cc: Minchan Kim <minchan.kim at gmail.com>
CC: Andrew Morton <akpm at linux-foundation.org>
CC: KOSAKI Motohiro <kosaki.motohiro at jp.fujitsu.com>
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki at jp.fujitsu.com>
Signed-off-by: Wen Congyang <wency at cn.fujitsu.com>
---
drivers/firmware/memmap.c | 98 +++++++++++++++++++++++++++++++++++++++++-
include/linux/firmware-map.h | 6 +++
mm/memory_hotplug.c | 9 +++-
3 files changed, 109 insertions(+), 4 deletions(-)
diff --git a/drivers/firmware/memmap.c b/drivers/firmware/memmap.c
index c1cdc92..6740d26 100644
--- 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 ------------------------------------------------------------------
@@ -41,6 +42,7 @@ struct firmware_map_entry {
const char *type; /* type of the memory range */
struct list_head list; /* entry for the linked list */
struct kobject kobj; /* kobject for each entry */
+ unsigned int bootmem:1; /* allocated from bootmem */
};
/*
@@ -79,7 +81,26 @@ 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 (entry->bootmem)
+ /* 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 +115,7 @@ 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 +140,25 @@ 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 +180,35 @@ 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.
@@ -193,9 +258,36 @@ int __init firmware_map_add_early(u64 start, u64 end, const char *type)
if (WARN_ON(!entry))
return -ENOMEM;
+ entry->bootmem = 1;
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 +309,10 @@ 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 43fe52f..71d4fa7 100644
--- 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 299747d..e74a01d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1052,9 +1052,9 @@ int offline_memory(u64 start, u64 size)
return 0;
}
-int remove_memory(int nid, u64 start, u64 size)
+int __ref remove_memory(int nid, u64 start, u64 size)
{
- int ret = -EBUSY;
+ int ret = 0;
lock_memory_hotplug();
/*
* The memory might become online by other task, even if you offine it.
@@ -1065,8 +1065,13 @@ int remove_memory(int nid, u64 start, u64 size)
"because the memmory range is online\n",
start, start + size);
ret = -EAGAIN;
+ goto out;
}
+ /* remove memmap entry */
+ firmware_map_remove(start, start + size, "System RAM");
+
+out:
unlock_memory_hotplug();
return ret;
--
1.7.1
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