[PATCH] Remove acpi_memory_info->failed bit

From: Yasuaki Ishimatsu
Date: Sun Mar 17 2013 - 22:20:47 EST

Hi Toshi,

Sorry for the late reply

2013/03/13 23:50, Toshi Kani wrote:
On Wed, 2013-03-13 at 15:54 +0900, Yasuaki Ishimatsu wrote:
At http://marc.info/?l=linux-acpi&m=135769405622667&w=2 thread,
Toshi Kani mentioned as follows:

"I have a question about the change you made in commit 65479472 in
acpi_memhotplug.c. This change seems to require that
acpi_memory_enable_device() calls add_memory() to add all memory ranges
represented by memory device objects at boot-time, and keep the results
be used for hot-remove.

If I understand it right, this add_memory() call fails with EEXIST at
boot-time since all memory ranges should have been added from EFI memory
table (or e820) already. This results all memory ranges be marked as !
enabled & !failed. I think this means that we cannot hot-delete any
memory ranges presented at boot-time since acpi_memory_remove_memory()
only calls remove_memory() when the enabled flag is set. Is that

Above mention is correct. Thus even if memory device supports hotplug,
memory presented at boot-time cannot be hot removed since the memory
device's acpi_memory_info->enabled is always 0.

This patch changes to set 1 to "acpi_memory_info->enabled" of memory
device presented at boot-time for hot removing the memory device.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>

drivers/acpi/acpi_memhotplug.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index da1f82b..88fd46a 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -254,8 +254,8 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)

- if (!result)
- info->enabled = 1;
+ info->enabled = 1;

Do we still need to keep the enable bit? I think !failed means enabled
with this change.

For controlling memory hotplug, we need either failed bit or enabled bit.
So I want to remove failed bit as follows:


acpi_memory_info has enabled bit and failed bit for controlling memory
hotplug. But we don't need to keep both bits.

The patch removes acpi_memory_info->failed bit.

Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
drivers/acpi/acpi_memhotplug.c | 15 ++-------------
1 files changed, 2 insertions(+), 13 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 88fd46a..cf4e1cf 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -79,7 +79,6 @@ 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 {
@@ -249,10 +248,8 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
* 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;
+ if (result && result != -EEXIST)
- }
info->enabled = 1;
@@ -286,16 +283,8 @@ static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
nid = acpi_get_node(mem_device->device->handle);
list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
- 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;
+ continue;
if (nid < 0)
nid = memory_add_physaddr_to_nid(info->start_addr);

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