[PATCH 2/8] v2 Add section count to memory_block struct

Nathan Fontenot
2010-09-27T19:22:32Z

Add a section count property to the memory_block struct to track the number
of memory sections that have been added/removed from a memory block. This
allows us to know when the last memory section of a memory block has been
removed so we can remove the memory block.

Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>

---
drivers/base/memory.c | 16 ++++++++++------
include/linux/memory.h | 3 +++
2 files changed, 13 insertions(+), 6 deletions(-)

Index: linux-next/drivers/base/memory.c
===================================================================
--- linux-next.orig/drivers/base/memory.c 2010-09-27 09:17:20.000000000 -0500
+++ linux-next/drivers/base/memory.c 2010-09-27 09:31:35.000000000 -0500
@@ -478,6 +478,7 @@

mem->phys_index = __section_nr(section);
mem->state = state;
+ atomic_inc(&mem->section_count);
mutex_init(&mem->state_mutex);
start_pfn = section_nr_to_pfn(mem->phys_index);
mem->phys_device = arch_get_memory_phys_device(start_pfn);
@@ -505,12 +506,15 @@
struct memory_block *mem;

mem = find_memory_block(section);
- unregister_mem_sect_under_nodes(mem);
- mem_remove_simple_file(mem, phys_index);
- mem_remove_simple_file(mem, state);
- mem_remove_simple_file(mem, phys_device);
- mem_remove_simple_file(mem, removable);
- unregister_memory(mem, section);
+
+ if (atomic_dec_and_test(&mem->section_count)) {
+ unregister_mem_sect_under_nodes(mem);
+ mem_remove_simple_file(mem, phys_index);
+ mem_remove_simple_file(mem, state);
+ mem_remove_simple_file(mem, phys_device);
+ mem_remove_simple_file(mem, removable);
+ unregister_memory(mem, section);
+ }

return 0;
}
Index: linux-next/include/linux/memory.h
===================================================================
--- linux-next.orig/include/linux/memory.h 2010-09-27 09:17:20.000000000 -0500
+++ linux-next/include/linux/memory.h 2010-09-27 09:22:56.000000000 -0500
@@ -19,10 +19,13 @@
#include <linux/node.h>
#include <linux/compiler.h>
#include <linux/mutex.h>
+#include <asm/atomic.h>

struct memory_block {
unsigned long phys_index;
unsigned long state;
+ atomic_t section_count;
+
/*
* This serializes all state change requests. It isn't
* held during creation because the control files are