linux-kernel - [PATCH v2 07/22] watchdog: ziirave_wdt: Check packet length only once

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Message-Id: <20190812200906.31344-8-andrew.smirnov@gmail.com>
Date:   Mon, 12 Aug 2019 13:08:51 -0700
From:   Andrey Smirnov <andrew.smirnov@...il.com>
To:     linux-watchdog@...r.kernel.org
Cc:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Chris Healy <cphealy@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Rick Ramstetter <rick@...eaterllc.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2 07/22] watchdog: ziirave_wdt: Check packet length only once

We don't need to check for packet length more than once, so drop the
extra check in ziirave_firm_upload(). While at it move the check at
the very start of __ziirave_firm_write_pkt(), as to not waste any time
preparing a packet we'll never use.

Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
Cc: Chris Healy <cphealy@...il.com>
Cc: Guenter Roeck <linux@...ck-us.net>
Cc: Rick Ramstetter <rick@...eaterllc.com>
Cc: linux-watchdog@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 drivers/watchdog/ziirave_wdt.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/watchdog/ziirave_wdt.c b/drivers/watchdog/ziirave_wdt.c
index b2d5ff0c22fe..9d9c669b8b47 100644
--- a/drivers/watchdog/ziirave_wdt.c
+++ b/drivers/watchdog/ziirave_wdt.c
@@ -253,6 +253,13 @@ static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
 	u8 i, checksum = 0, packet[ZIIRAVE_FIRM_PKT_TOTAL_SIZE];
 	int ret;
 
+	/* Check max data size */
+	if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
+		dev_err(&client->dev, "Firmware packet too long (%d)\n",
+			len);
+		return -EMSGSIZE;
+	}
+
 	memset(packet, 0, ARRAY_SIZE(packet));
 
 	/* Packet length */
@@ -261,9 +268,6 @@ static int __ziirave_firm_write_pkt(struct watchdog_device *wdd,
 	packet[1] = addr16 & 0xff;
 	packet[2] = (addr16 & 0xff00) >> 8;
 
-	/* Packet data */
-	if (len > ZIIRAVE_FIRM_PKT_DATA_SIZE)
-		return -EMSGSIZE;
 	memcpy(packet + 3, data, len);
 
 	/* Packet checksum */
@@ -382,13 +386,6 @@ static int ziirave_firm_upload(struct watchdog_device *wdd,
 		if (!be16_to_cpu(rec->len))
 			break;
 
-		/* Check max data size */
-		if (be16_to_cpu(rec->len) > ZIIRAVE_FIRM_PKT_DATA_SIZE) {
-			dev_err(&client->dev, "Firmware packet too long (%d)\n",
-				be16_to_cpu(rec->len));
-			return -EMSGSIZE;
-		}
-
 		ret = ziirave_firm_write_pkt(wdd, be32_to_cpu(rec->addr),
 					     rec->data, be16_to_cpu(rec->len));
 		if (ret)
-- 
2.21.0