From 46c66c4b7ba0f9bb3e2ae3a3cfd40cd3472c8f80 Mon Sep 17 00:00:00 2001 From: Yasuaki Ishimatsu Date: Fri, 22 Feb 2013 16:32:56 -0800 Subject: 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. This patch implements the function to remove them. We cannot free firmware_map_entry which is allocated by bootmem because there is no way to do so when the system is up. But we can at least remember the address of that memory and reuse the storage when the memory is added next time. This patch also introduces a new list map_entries_bootmem to link the map entries allocated by bootmem when they are removed, and a lock to protect it. And these entries will be reused when the memory is hot-added again. The idea is suggestted by Andrew Morton. NOTE: It is unsafe to return an entry pointer and release the map_entries_lock. So we should not hold the map_entries_lock separately in firmware_map_find_entry() and firmware_map_remove_entry(). Hold the map_entries_lock across find and remove /sys/firmware/memmap/X operation. And also, users of these two functions need to be careful to hold the lock when using these two functions. [tangchen@cn.fujitsu.com: Hold spinlock across find|remove /sys operation] [tangchen@cn.fujitsu.com: fix the wrong comments of map_entries] [tangchen@cn.fujitsu.com: reuse the storage of /sys/firmware/memmap/X/ allocated by bootmem] [tangchen@cn.fujitsu.com: fix section mismatch problem] [tangchen@cn.fujitsu.com: fix the doc format in drivers/firmware/memmap.c] Signed-off-by: Wen Congyang Signed-off-by: Yasuaki Ishimatsu Signed-off-by: Tang Chen Reviewed-by: Kamezawa Hiroyuki Cc: KOSAKI Motohiro Cc: Jiang Liu Cc: Jianguo Wu Cc: Lai Jiangshan Cc: Tang Chen Cc: Ingo Molnar Cc: Thomas Gleixner Cc: "H. Peter Anvin" Cc: Julian Calaby Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/firmware-map.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux/firmware-map.h') diff --git a/include/linux/firmware-map.h b/include/linux/firmware-map.h index 43fe52fcef0f..71d4fa721db9 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 */ -- cgit v1.2.3