From fa2be40fe7c0aa3b7accbf6dfa9ef0976e191d4c Mon Sep 17 00:00:00 2001 From: Seth Jennings Date: Tue, 20 Aug 2013 16:05:05 -0500 Subject: [PATCH] drivers: base: use standard device online/offline for state change There are two ways to set the online/offline state for a memory block: echo 0|1 > online and echo online|online_kernel|online_movable|offline > state. The state attribute can online a memory block with extra data, the "online type", where the online attribute uses a default online type of ONLINE_KEEP, same as echo online > state. Currently there is a state_mutex that provides consistency between the memory block state and the underlying memory. The problem is that this code does a lot of things that the common device layer can do for us, such as the serialization of the online/offline handlers using the device lock, setting the dev->offline field, and calling kobject_uevent(). This patch refactors the online/offline code to allow the common device_[online|offline] functions to be used. The result is a simpler and more common code path for the two state setting mechanisms. It also removes the state_mutex from the struct memory_block as the memory block device lock provides the state consistency. No functional change is intended by this patch. Signed-off-by: Seth Jennings Signed-off-by: Greg Kroah-Hartman --- drivers/base/memory.c | 127 ++++++++++++++++++----------------------- include/linux/memory.h | 13 +---- 2 files changed, 58 insertions(+), 82 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 0187fe483d7c..2a38cd2da2e5 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -16,7 +16,6 @@ #include #include #include -#include #include #include #include @@ -261,9 +260,8 @@ memory_block_action(unsigned long phys_index, unsigned long action, int online_t return ret; } -static int __memory_block_change_state(struct memory_block *mem, - unsigned long to_state, unsigned long from_state_req, - int online_type) +static int memory_block_change_state(struct memory_block *mem, + unsigned long to_state, unsigned long from_state_req) { int ret = 0; @@ -273,105 +271,91 @@ static int __memory_block_change_state(struct memory_block *mem, if (to_state == MEM_OFFLINE) mem->state = MEM_GOING_OFFLINE; - ret = memory_block_action(mem->start_section_nr, to_state, online_type); + ret = memory_block_action(mem->start_section_nr, to_state, + mem->online_type); + mem->state = ret ? from_state_req : to_state; + return ret; } +/* The device lock serializes operations on memory_subsys_[online|offline] */ static int memory_subsys_online(struct device *dev) { struct memory_block *mem = container_of(dev, struct memory_block, dev); int ret; - mutex_lock(&mem->state_mutex); + if (mem->state == MEM_ONLINE) + return 0; - ret = mem->state == MEM_ONLINE ? 0 : - __memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE, - ONLINE_KEEP); + /* + * If we are called from store_mem_state(), online_type will be + * set >= 0 Otherwise we were called from the device online + * attribute and need to set the online_type. + */ + if (mem->online_type < 0) + mem->online_type = ONLINE_KEEP; + + ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE); + + /* clear online_type */ + mem->online_type = -1; - mutex_unlock(&mem->state_mutex); return ret; } static int memory_subsys_offline(struct device *dev) { struct memory_block *mem = container_of(dev, struct memory_block, dev); - int ret; - mutex_lock(&mem->state_mutex); - - ret = mem->state == MEM_OFFLINE ? 0 : - __memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE, -1); - - mutex_unlock(&mem->state_mutex); - return ret; -} + if (mem->state == MEM_OFFLINE) + return 0; -static int __memory_block_change_state_uevent(struct memory_block *mem, - unsigned long to_state, unsigned long from_state_req, - int online_type) -{ - int ret = __memory_block_change_state(mem, to_state, from_state_req, - online_type); - if (!ret) { - switch (mem->state) { - case MEM_OFFLINE: - kobject_uevent(&mem->dev.kobj, KOBJ_OFFLINE); - break; - case MEM_ONLINE: - kobject_uevent(&mem->dev.kobj, KOBJ_ONLINE); - break; - default: - break; - } - } - return ret; + return memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE); } -static int memory_block_change_state(struct memory_block *mem, - unsigned long to_state, unsigned long from_state_req, - int online_type) -{ - int ret; - - mutex_lock(&mem->state_mutex); - ret = __memory_block_change_state_uevent(mem, to_state, from_state_req, - online_type); - mutex_unlock(&mem->state_mutex); - - return ret; -} static ssize_t store_mem_state(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct memory_block *mem; - bool offline; - int ret = -EINVAL; + int ret, online_type; mem = container_of(dev, struct memory_block, dev); lock_device_hotplug(); - if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) { - offline = false; - ret = memory_block_change_state(mem, MEM_ONLINE, - MEM_OFFLINE, ONLINE_KERNEL); - } else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) { - offline = false; - ret = memory_block_change_state(mem, MEM_ONLINE, - MEM_OFFLINE, ONLINE_MOVABLE); - } else if (!strncmp(buf, "online", min_t(int, count, 6))) { - offline = false; - ret = memory_block_change_state(mem, MEM_ONLINE, - MEM_OFFLINE, ONLINE_KEEP); - } else if(!strncmp(buf, "offline", min_t(int, count, 7))) { - offline = true; - ret = memory_block_change_state(mem, MEM_OFFLINE, - MEM_ONLINE, -1); + if (!strncmp(buf, "online_kernel", min_t(int, count, 13))) + online_type = ONLINE_KERNEL; + else if (!strncmp(buf, "online_movable", min_t(int, count, 14))) + online_type = ONLINE_MOVABLE; + else if (!strncmp(buf, "online", min_t(int, count, 6))) + online_type = ONLINE_KEEP; + else if (!strncmp(buf, "offline", min_t(int, count, 7))) + online_type = -1; + else + return -EINVAL; + + switch (online_type) { + case ONLINE_KERNEL: + case ONLINE_MOVABLE: + case ONLINE_KEEP: + /* + * mem->online_type is not protected so there can be a + * race here. However, when racing online, the first + * will succeed and the second will just return as the + * block will already be online. The online type + * could be either one, but that is expected. + */ + mem->online_type = online_type; + ret = device_online(&mem->dev); + break; + case -1: + ret = device_offline(&mem->dev); + break; + default: + ret = -EINVAL; /* should never happen */ } - if (!ret) - dev->offline = offline; unlock_device_hotplug(); @@ -592,7 +576,6 @@ static int init_memory_block(struct memory_block **memory, mem->end_section_nr = mem->start_section_nr + sections_per_block - 1; mem->state = state; mem->section_count++; - mutex_init(&mem->state_mutex); start_pfn = section_nr_to_pfn(mem->start_section_nr); mem->phys_device = arch_get_memory_phys_device(start_pfn); diff --git a/include/linux/memory.h b/include/linux/memory.h index 4c89fb0c8f4c..9a6bbf76452d 100644 --- a/include/linux/memory.h +++ b/include/linux/memory.h @@ -25,16 +25,9 @@ struct memory_block { unsigned long start_section_nr; unsigned long end_section_nr; - unsigned long state; - int section_count; - - /* - * This serializes all state change requests. It isn't - * held during creation because the control files are - * created long after the critical areas during - * initialization. - */ - struct mutex state_mutex; + unsigned long state; /* serialized by the dev->lock */ + int section_count; /* serialized by mem_sysfs_mutex */ + int online_type; /* for passing data to online routine */ int phys_device; /* to which fru does this belong? */ void *hw; /* optional pointer to fw/hw data */ int (*phys_callback)(struct memory_block *); -- 2.20.1