linux-kernel - [PATCH] acpi: osl: Replace GFP_ATOMIC with GFP_KERNEL in acpi_os

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Date:   Thu, 25 Jan 2018 18:13:41 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     rjw@...ysocki.net, lenb@...nel.org
Cc:     linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
Subject: [PATCH] acpi: osl: Replace GFP_ATOMIC with GFP_KERNEL in acpi_os_execute

After checking all possible call chains to acpi_os_execute here,
my tool finds that acpi_os_execute is never called in atomic context.
And acpi_os_execute calls acpi_debugger_create_thread 
which calls mutex_lock,
thus it proves again that acpi_os_execute can 
call functions which may sleep.
Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
---
 drivers/acpi/osl.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 3bb46cb..8ee605e 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -1066,7 +1066,7 @@ acpi_status acpi_os_execute(acpi_execute_type type,
 	 * having a static work_struct.
 	 */

-	dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_ATOMIC);
+	dpc = kzalloc(sizeof(struct acpi_os_dpc), GFP_KERNEL);
 	if (!dpc)
 		return AE_NO_MEMORY;

-- 
1.7.9.5