wency at cn
Jun 26, 2012, 2:20 AM
Post #1 of 3
(56 views)
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[PATCH 4/8] donot allow to eject the memory device if it is being used
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We eject the memory device even if it is in use. It is very dangerous,
and it will cause the kernel panicked.
Signed-off-by: Wen Congyang <wency [at] cn>
---
drivers/acpi/acpi_memhotplug.c | 34 +++++++++++++++++++++++++++-------
1 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index a325bb9..2e5d5ab 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -78,6 +78,7 @@ struct acpi_memory_info {
unsigned short caching; /* memory cache attribute */
unsigned short write_protect; /* memory read/write attribute */
unsigned int enabled:1;
+ unsigned int failed:1;
};
struct acpi_memory_device {
@@ -251,9 +252,19 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
node = memory_add_physaddr_to_nid(info->start_addr);
result = add_memory(node, info->start_addr, info->length);
- if (result)
+
+ /*
+ * If the memory block has been used by the kernel, add_memory()
+ * returns -EEXIST. If add_memory() returns the other error, it
+ * means that this memory block is not used by the kernel.
+ */
+ if (result && result != -EEXIST) {
+ info->failed = 1;
continue;
- info->enabled = 1;
+ }
+
+ if (!result)
+ info->enabled = 1;
num_enabled++;
}
if (!num_enabled) {
@@ -317,11 +328,20 @@ static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
* Note: Assume that this function returns zero on success
*/
list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
- if (info->enabled) {
- result = remove_memory(info->start_addr, info->length);
- if (result)
- return result;
- }
+ if (info->failed)
+ /* The kernel does not use this memory block */
+ continue;
+
+ if (!info->enabled)
+ /*
+ * The kernel uses this memory block, but it may be not
+ * managed by us.
+ */
+ return -EBUSY;
+
+ result = remove_memory(info->start_addr, info->length);
+ if (result)
+ return result;
list_del(&info->list);
kfree(info);
}
--
1.7.1
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