linux-kernel - [RFC PATCH] ACPI / EC: Fix an order issue in ec_remove

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Date:	Thu,  7 Jul 2016 09:49:28 +0800
From:	Lv Zheng <lv.zheng@...el.com>
To:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>
Cc:	Lv Zheng <lv.zheng@...el.com>, Lv Zheng <zetalog@...il.com>,
	<linux-kernel@...r.kernel.org>, linux-acpi@...r.kernel.org,
	Wolfram Sang <wsa@...-dreams.de>,
	Nicholas <nkudriavtsev@...il.com>
Subject: [RFC PATCH] ACPI / EC: Fix an order issue in ec_remove_handlers()

There is an order issue in ec_remove_handlers() that the functions invoked
in it are not invoked in the reversed order of their appearance in
ec_install_handlers(). This existing issue has been triggered by the
following commit:
  Commit: dcf15cbded656a12335bc4151f3f75f10080a375
  Subject: ACPI / EC: Fix a boot EC regresion by restoring boot EC
The commit invokes ec_remove_handlers() during runtime, thus uncovers this
issue. This patch fixes this regression.

Fixes: dcf15cbded65 ("ACPI / EC: Fix a boot EC regresion by restoring boot EC")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=102421
Reported-by: Wolfram Sang <wsa@...-dreams.de>
Reported-by: Nicholas <nkudriavtsev@...il.com>
Cc: Wolfram Sang <wsa@...-dreams.de>
Cc: Nicholas <nkudriavtsev@...il.com>
Signed-off-by: Lv Zheng <lv.zheng@...el.com>
---
 drivers/acpi/ec.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index b1050a0..9ff3d4b 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1331,7 +1331,12 @@ static int ec_install_handlers(struct acpi_ec *ec)
 
 static void ec_remove_handlers(struct acpi_ec *ec)
 {
-	acpi_ec_stop(ec, false);
+	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
+		if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
+					&acpi_ec_gpe_handler)))
+			pr_err("failed to remove gpe handler\n");
+		clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
+	}
 
 	if (test_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags)) {
 		if (ACPI_FAILURE(acpi_remove_address_space_handler(ec->handle,
@@ -1340,12 +1345,7 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 		clear_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
 	}
 
-	if (test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
-		if (ACPI_FAILURE(acpi_remove_gpe_handler(NULL, ec->gpe,
-					&acpi_ec_gpe_handler)))
-			pr_err("failed to remove gpe handler\n");
-		clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
-	}
+	acpi_ec_stop(ec, false);
 }
 
 static struct acpi_ec *acpi_ec_alloc(void)
-- 
1.7.10