linux-kernel - [PATCH 2/3] i2c: Add pointer dereference protection to i2c_match

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Date:	Mon,  2 Jun 2014 14:41:02 +0100
From:	Lee Jones <lee.jones@...aro.org>
To:	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	wsa@...-dreams.de
Cc:	linus.walleij@...aro.org, grant.likely@...aro.org,
	linux-i2c@...r.kernel.org, Lee Jones <lee.jones@...aro.org>
Subject: [PATCH 2/3] i2c: Add pointer dereference protection to i2c_match_id()

Here we're providing dereference protection for i2c_match_id(), which
saves us having to do it each time it's called.  We're also stripping
out the (now) needless check in i2c_device_match().  This patch paves
the way for other, similar code trimming.

Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
 drivers/i2c/i2c-core.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 2e47641..d0c7180 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -83,6 +83,9 @@ void i2c_transfer_trace_unreg(void)
 static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
 						const struct i2c_client *client)
 {
+	if (!id)
+		return NULL;
+
 	while (id->name[0]) {
 		if (strcmp(client->name, id->name) == 0)
 			return id;
@@ -108,9 +111,10 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
 		return 1;
 
 	driver = to_i2c_driver(drv);
-	/* match on an id table if there is one */
-	if (driver->id_table)
-		return i2c_match_id(driver->id_table, client) != NULL;
+
+	/* Finally an I2C match */
+	if (i2c_match_id(driver->id_table, client))
+		return 1;
 
 	return 0;
 }
-- 
1.8.3.2

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