[PATCH 2/10] memory-hotplug : remove /sys/firmware/memmap/X sysfs
From: Yasuaki Ishimatsu <hidden>
Date: 2012-10-05 02:27:36
Also in:
linux-acpi, linux-mm, linux-s390, linuxppc-dev, lkml, sparclinux
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@google.com>
CC: Jiang Liu <redacted>
CC: Len Brown <redacted>
CC: Christoph Lameter <redacted>
Cc: Minchan Kim <redacted>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: KOSAKI Motohiro <redacted>
Signed-off-by: Wen Congyang <redacted>
Signed-off-by: Yasuaki Ishimatsu <redacted>
---
drivers/firmware/memmap.c | 98 ++++++++++++++++++++++++++++++++++++++++++-
include/linux/firmware-map.h | 6 ++
mm/memory_hotplug.c | 7 ++-
3 files changed, 108 insertions(+), 3 deletions(-)
Index: linux-3.6/drivers/firmware/memmap.c
=================================--- linux-3.6.orig/drivers/firmware/memmap.c 2012-10-04 18:27:05.195500420 +0900+++ linux-3.6/drivers/firmware/memmap.c 2012-10-04 18:27:18.901514330 +0900@@ -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_att .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 st 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 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 st 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 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)
Index: linux-3.6/include/linux/firmware-map.h =================================--- linux-3.6.orig/include/linux/firmware-map.h 2012-10-04 18:27:05.197500422 +0900
+++ linux-3.6/include/linux/firmware-map.h 2012-10-04 18:27:18.904514333 +0900@@ -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_hotpl 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 */
Index: linux-3.6/mm/memory_hotplug.c =================================--- linux-3.6.orig/mm/memory_hotplug.c 2012-10-04 18:27:03.000000000 +0900
+++ linux-3.6/mm/memory_hotplug.c 2012-10-04 18:28:42.851599524 +0900@@ -1043,7 +1043,7 @@ 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 = 0; lock_memory_hotplug();
@@ -1056,8 +1056,13 @@ int remove_memory(int nid, u64 start, u6 "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; }