From 6330c7070be6783b82025d2bc259db8413c00182 Mon Sep 17 00:00:00 2001
From: Sachin Kamat <sachin.kamat@linaro.org>
Date: Mon, 4 Mar 2013 10:36:41 +0530
Subject: watchdog: Convert to devm_ioremap_resource()

Use the newly introduced devm_ioremap_resource() instead of
devm_request_and_ioremap() which provides more consistent error handling.

devm_ioremap_resource() provides its own error messages; so all explicit
error messages can be removed from the failure code paths.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Thierry Reding <thierry.reding@avionic-design.de>
Cc: Gabor Juhos <juhosg@openwrt.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/ath79_wdt.c b/drivers/watchdog/ath79_wdt.c
index 8987990..d184c48 100644
--- a/drivers/watchdog/ath79_wdt.c
+++ b/drivers/watchdog/ath79_wdt.c
@@ -253,11 +253,9 @@ static int ath79_wdt_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	wdt_base = devm_request_and_ioremap(&pdev->dev, res);
-	if (!wdt_base) {
-		dev_err(&pdev->dev, "unable to remap memory region\n");
-		return -ENOMEM;
-	}
+	wdt_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(wdt_base))
+		return PTR_ERR(wdt_base);
 
 	wdt_clk = devm_clk_get(&pdev->dev, "wdt");
 	if (IS_ERR(wdt_clk))
diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c
index 7df1fdc..100d4fb 100644
--- a/drivers/watchdog/davinci_wdt.c
+++ b/drivers/watchdog/davinci_wdt.c
@@ -27,6 +27,7 @@
 #include <linux/device.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
+#include <linux/err.h>
 
 #define MODULE_NAME "DAVINCI-WDT: "
 
@@ -221,11 +222,9 @@ static int davinci_wdt_probe(struct platform_device *pdev)
 		return -ENOENT;
 	}
 
-	wdt_base = devm_request_and_ioremap(dev, wdt_mem);
-	if (!wdt_base) {
-		dev_err(dev, "ioremap failed\n");
-		return -EADDRNOTAVAIL;
-	}
+	wdt_base = devm_ioremap_resource(dev, wdt_mem);
+	if (IS_ERR(wdt_base))
+		return PTR_ERR(wdt_base);
 
 	ret = misc_register(&davinci_wdt_miscdev);
 	if (ret < 0) {
diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
index c1a221c..ee03135 100644
--- a/drivers/watchdog/s3c2410_wdt.c
+++ b/drivers/watchdog/s3c2410_wdt.c
@@ -330,10 +330,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
 	}
 
 	/* get the memory region for the watchdog timer */
-	wdt_base = devm_request_and_ioremap(dev, wdt_mem);
-	if (wdt_base == NULL) {
-		dev_err(dev, "failed to devm_request_and_ioremap() region\n");
-		ret = -ENOMEM;
+	wdt_base = devm_ioremap_resource(dev, wdt_mem);
+	if (IS_ERR(wdt_base)) {
+		ret = PTR_ERR(wdt_base);
 		goto err;
 	}
 
diff --git a/drivers/watchdog/shwdt.c b/drivers/watchdog/shwdt.c
index 6a89e40..6185af2 100644
--- a/drivers/watchdog/shwdt.c
+++ b/drivers/watchdog/shwdt.c
@@ -34,6 +34,7 @@
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/clk.h>
+#include <linux/err.h>
 #include <asm/watchdog.h>
 
 #define DRV_NAME "sh-wdt"
@@ -249,9 +250,9 @@ static int sh_wdt_probe(struct platform_device *pdev)
 		wdt->clk = NULL;
 	}
 
-	wdt->base = devm_request_and_ioremap(wdt->dev, res);
-	if (unlikely(!wdt->base)) {
-		rc = -EADDRNOTAVAIL;
+	wdt->base = devm_ioremap_resource(wdt->dev, res);
+	if (IS_ERR(wdt->base)) {
+		rc = PTR_ERR(wdt->base);
 		goto err;
 	}
 
-- 
cgit v0.10.2


From 60403f7a4d9368d187f79cba5e4672d01df37574 Mon Sep 17 00:00:00 2001
From: Guenter Roeck <linux@roeck-us.net>
Date: Fri, 5 Apr 2013 21:22:43 -0700
Subject: watchdog: Fix race condition in registration code

A race condition exists when registering the first watchdog device.
Sequence of events:

- watchdog_register_device calls watchdog_dev_register
- watchdog_dev_register creates the watchdog misc device by calling
  misc_register.
  At that time, the matching character device (/dev/watchdog0) does not yet
  exist, and old_wdd is not set either.
- Userspace gets an event and opens /dev/watchdog
- watchdog_open is called and sets wdd = old_wdd, which is still NULL,
  and tries to dereference it. This causes the kernel to panic.

Seen with systemd trying to open /dev/watchdog immediately after
it was created.

Reported-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Arkadiusz Miskiewicz <arekm@maven.pl>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 08b48bb..faf4e18 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -523,6 +523,7 @@ int watchdog_dev_register(struct watchdog_device *watchdog)
 	int err, devno;
 
 	if (watchdog->id == 0) {
+		old_wdd = watchdog;
 		watchdog_miscdev.parent = watchdog->parent;
 		err = misc_register(&watchdog_miscdev);
 		if (err != 0) {
@@ -531,9 +532,9 @@ int watchdog_dev_register(struct watchdog_device *watchdog)
 			if (err == -EBUSY)
 				pr_err("%s: a legacy watchdog module is probably present.\n",
 					watchdog->info->identity);
+			old_wdd = NULL;
 			return err;
 		}
-		old_wdd = watchdog;
 	}
 
 	/* Fill in the data structures */
-- 
cgit v0.10.2