[PATCH] drivers:block:mtip32xx:mtip32xx:change the order of null-pointer dereference validation

From	Heloise <os@iscas.ac.cn>
Newsgroups	linux.kernel
Subject	[PATCH] drivers:block:mtip32xx:mtip32xx:change the order of null-pointer dereference validation
Date	2017-04-26 03:40 +0200
Message-ID	<tAk5X-3X0-5@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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Signed-off-by: Heloise <os@iscas.ac.cn>

mtip_async_complete() uses the variable port 'port->dd'at the begining, then
validates null-pointer dereference of port 'unlikely(!port)'. Change the order
of validation.
---
 drivers/block/mtip32xx/mtip32xx.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
index 1d1dc11..feed61a 100644
--- a/drivers/block/mtip32xx/mtip32xx.c
+++ b/drivers/block/mtip32xx/mtip32xx.c
@@ -228,10 +228,13 @@ static struct mtip_cmd *mtip_cmd_from_tag(struct driver_data *dd,
 static void mtip_async_complete(struct mtip_port *port,
 				int tag, struct mtip_cmd *cmd, int status)
 {
+	if (unlikely(!port))
+		return;
+
 	struct driver_data *dd = port->dd;
 	struct request *rq;
 
-	if (unlikely(!dd) || unlikely(!port))
+	if (unlikely(!dd))
 		return;
 
 	if (unlikely(status == PORT_IRQ_TF_ERR)) {
-- 
2.1.0

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[PATCH] drivers:block:mtip32xx:mtip32xx:change the order of null-pointer dereference validation Heloise <os@iscas.ac.cn> - 2017-04-26 03:40 +0200

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