linux-kernel - [PATCH] Watchdog: Checking timeout invalid if hardware heartbeat range is configured

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Date:   Thu, 21 Apr 2022 22:22:18 +0800
From:   Liu Xinpeng <liuxp11@...natelecom.cn>
To:     wim@...ux-watchdog.org, linux@...ck-us.net
Cc:     linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org,
        Liu Xinpeng <liuxp11@...natelecom.cn>
Subject: [PATCH] Watchdog: Checking timeout invalid if hardware heartbeat range is configured

The timeout should be invalid when it is out of the hardware
timeout range.

ACPI watchdog: Using watchdog_timeout_invalid to check parameter
timeout invalid

Signed-off-by: Liu Xinpeng <liuxp11@...natelecom.cn>
---
 drivers/watchdog/wdat_wdt.c |  3 +--
 include/linux/watchdog.h    | 17 ++++++++++++-----
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
index 195c8c004b69..d166d33ce7ae 100644
--- a/drivers/watchdog/wdat_wdt.c
+++ b/drivers/watchdog/wdat_wdt.c
@@ -450,8 +450,7 @@ static int wdat_wdt_probe(struct platform_device *pdev)
 	 * watchdog properly after it has opened the device. In some cases
 	 * the BIOS default is too short and causes immediate reboot.
 	 */
-	if (timeout * 1000 < wdat->wdd.min_hw_heartbeat_ms ||
-	    timeout * 1000 > wdat->wdd.max_hw_heartbeat_ms) {
+	if (watchdog_timeout_invalid(&wdat->wdd, timeout)) {
 		dev_warn(dev, "Invalid timeout %d given, using %d\n",
 			 timeout, WDAT_DEFAULT_TIMEOUT);
 		timeout = WDAT_DEFAULT_TIMEOUT;
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 99660197a36c..e82daeef0b26 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -167,6 +167,15 @@ static inline void watchdog_stop_ping_on_suspend(struct watchdog_device *wdd)
 /* Use the following function to check if a timeout value is invalid */
 static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigned int t)
 {
+	/*
+	 * If a maximum/minimum hardware timeout is configured,
+	 * the timeout is invalid when it is out of the range.
+	 */
+	if (wdd->max_hw_heartbeat_ms)
+		return t * 1000 > wdd->max_hw_heartbeat_ms;
+	if (wdd->min_hw_heartbeat_ms)
+		return t * 1000 < wdd->min_hw_heartbeat_ms;
+
 	/*
 	 * The timeout is invalid if
 	 * - the requested value is larger than UINT_MAX / 1000
@@ -174,13 +183,11 @@ static inline bool watchdog_timeout_invalid(struct watchdog_device *wdd, unsigne
 	 * or
 	 * - the requested value is smaller than the configured minimum timeout,
 	 * or
-	 * - a maximum hardware timeout is not configured, a maximum timeout
-	 *   is configured, and the requested value is larger than the
-	 *   configured maximum timeout.
+	 * - maximum timeout is configured, and the requested value is larger than
+	 * the configured maximum timeout.
 	 */
 	return t > UINT_MAX / 1000 || t < wdd->min_timeout ||
-		(!wdd->max_hw_heartbeat_ms && wdd->max_timeout &&
-		 t > wdd->max_timeout);
+		(wdd->max_timeout && t > wdd->max_timeout);
 }
 
 /* Use the following function to check if a pretimeout value is invalid */
-- 
2.23.0