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From: Nathan Fontenot on 12 Jul 2010 11:50
This patch introduces the new 'split' file in each memory sysfs
directory and the associated routines needed to handle splitting
a directory.

Signed-off-by; Nathan Fontenot <nfont(a)austin.ibm.com>
---
drivers/base/memory.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 98 insertions(+), 1 deletion(-)

Index: linux-2.6/drivers/base/memory.c
===================================================================
--- linux-2.6.orig/drivers/base/memory.c 2010-07-09 14:23:20.000000000 -0500
+++ linux-2.6/drivers/base/memory.c 2010-07-09 14:38:09.000000000 -0500
@@ -32,6 +32,9 @@

static int sections_per_block;

+static int register_memory(struct memory_block *, struct mem_section *,
+ int, enum mem_add_context);
+
static inline int base_memory_block_id(int section_nr)
{
return (section_nr / sections_per_block) * sections_per_block;
@@ -309,11 +312,100 @@
return sprintf(buf, "%d\n", mem->phys_device);
}

+static void update_memory_block_phys_indexes(struct memory_block *mem)
+{
+ struct list_head *pos;
+ struct memory_block_section *mbs;
+ unsigned long min_index = 0xffffffff;
+ unsigned long max_index = 0;
+
+ list_for_each(pos, &mem->sections) {
+ mbs = list_entry(pos, struct memory_block_section, next);
+
+ if (mbs->phys_index < min_index)
+ min_index = mbs->phys_index;
+
+ if (mbs->phys_index > max_index)
+ max_index = mbs->phys_index;
+ }
+
+ mem->start_phys_index = min_index;
+ mem->end_phys_index = max_index;
+}
+
+static ssize_t
+store_mem_split_block(struct sys_device *dev, struct sysdev_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct memory_block *mem, *new_mem_blk;
+ struct memory_block_section *mbs;
+ struct list_head *pos, *tmp;
+ struct mem_section *section;
+ int min_scn_nr = 0;
+ int max_scn_nr = 0;
+ int total_scns = 0;
+ int new_blk_min, new_blk_total;
+ int ret = -EINVAL;
+
+ mem = container_of(dev, struct memory_block, sysdev);
+
+ if (list_is_singular(&mem->sections))
+ return -EINVAL;
+
+ mutex_lock(&mem->state_mutex);
+
+ list_for_each(pos, &mem->sections) {
+ mbs = list_entry(pos, struct memory_block_section, next);
+
+ total_scns++;
+
+ if (min_scn_nr > mbs->phys_index)
+ min_scn_nr = mbs->phys_index;
+
+ if (max_scn_nr < mbs->phys_index)
+ max_scn_nr = mbs->phys_index;
+ }
+
+ new_mem_blk = kzalloc(sizeof(*new_mem_blk), GFP_KERNEL);
+ if (!new_mem_blk)
+ return -ENOMEM;
+
+ mutex_init(&new_mem_blk->state_mutex);
+ INIT_LIST_HEAD(&new_mem_blk->sections);
+ new_mem_blk->state = mem->state;
+
+ mutex_lock(&new_mem_blk->state_mutex);
+
+ new_blk_total = total_scns / 2;
+ new_blk_min = max_scn_nr - new_blk_total + 1;
+
+ section = __nr_to_section(new_blk_min);
+ ret = register_memory(new_mem_blk, section, 0, HOTPLUG);
+
+ list_for_each_safe(pos, tmp, &mem->sections) {
+ unsigned long scn_nr;
+
+ mbs = list_entry(pos, struct memory_block_section, next);
+ scn_nr = mbs->phys_index;
+
+ if ((scn_nr >= new_blk_min) && (scn_nr <= max_scn_nr))
+ list_move(&mbs->next, &new_mem_blk->sections);
+ }
+
+ update_memory_block_phys_indexes(mem);
+ update_memory_block_phys_indexes(new_mem_blk);
+
+ mutex_unlock(&new_mem_blk->state_mutex);
+ mutex_unlock(&mem->state_mutex);
+ return count;
+}
+
static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
static SYSDEV_ATTR(end_phys_index, 0444, show_mem_end_phys_index, NULL);
static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
+static SYSDEV_ATTR(split, 0200, NULL, store_mem_split_block);

#define mem_create_simple_file(mem, attr_name) \
sysdev_create_file(&mem->sysdev, &attr_##attr_name)
@@ -343,6 +435,8 @@
ret = mem_create_simple_file(memory, phys_device);
if (!ret)
ret = mem_create_simple_file(memory, removable);
+ if (!ret)
+ ret = mem_create_simple_file(memory, split);
if (!ret) {
if (context == HOTPLUG)
ret = register_mem_sect_under_node(memory, nid);
@@ -361,6 +455,7 @@
mem_remove_simple_file(memory, state);
mem_remove_simple_file(memory, phys_device);
mem_remove_simple_file(memory, removable);
+ mem_remove_simple_file(memory, split);

/* drop the ref. we got in remove_memory_block() */
kobject_put(&memory->sysdev.kobj);
@@ -568,8 +663,10 @@
kobject_put(&mem->sysdev.kobj);
}

- if (!ret)
+ if (!ret) {
ret = add_mem_block_section(mem, __section_nr(section), state);
+ update_memory_block_phys_indexes(mem);
+ }

return ret;
}
--
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Prev: [PATCH 6/7] Update sysfs node routines for new sysfs memory directories
Next: Hang observed while reading a block device using a simple block driver using the file as a back-end data store