linux-kernel - [Bug fix PATCH v2 1/2] ACPI,acpi_memhotplug: enable acpi_memory_info->enabled of memory device presented at boot-time

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Message-ID: <514A8E3C.1050902@jp.fujitsu.com>
Date:	Thu, 21 Mar 2013 13:36:12 +0900
From:	Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To:	Toshi Kani <toshi.kani@...com>, <rjw@...k.pl>
CC:	<linux-acpi@...r.kernel.org>, <tangchen@...fujitsu.com>,
	<wency@...fujitsu.com>, <laijs@...fujitsu.com>,
	<linux-kernel@...r.kernel.org>
Subject: [Bug fix PATCH v2 1/2] ACPI,acpi_memhotplug: enable acpi_memory_info->enabled
 of memory device presented at boot-time

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
correct?"

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@...fujitsu.com>
---

v2 : Changed a based kernel from linux-3.9-rc2 to linux-pm.git/bleeding-edge.

---
  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 d4f2eb8..ea78988 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -206,8 +206,8 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
  			continue;
  		}

-		if (!result)
-			info->enabled = 1;
+		info->enabled = 1;
+
  		/*
  		 * Add num_enable even if add_memory() returns -EEXIST, so the
  		 * device is bound to this driver.

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