[39/46] ALSA: Dont assume i2c device probing always succeeds

[Greg KH]

2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Takashi Iwai <tiwai@xxxxxxx>

commit 18c4078489fe064cc0ed08be3381cf2f26657f5f upstream.

The client->driver pointer can be NULL when i2c-device probing fails
in i2c_new_device().  This patch adds the NULL checks for client->driver
and return the error instead of blind assumption of driver availability.

Reported-by: Tim Shepard <shep@xxxxxxxxxxxx>
Cc: Jean Delvare <khali@xxxxxxxxxxxx>
Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

--- a/sound/aoa/codecs/tas.c
+++ b/sound/aoa/codecs/tas.c
@@ -897,6 +897,15 @@ static int tas_create(struct i2c_adapter *adapter,
 	client = i2c_new_device(adapter, &info);
 	if (!client)
 		return -ENODEV;
+	/*
+	 * We know the driver is already loaded, so the device should be
+	 * already bound. If not it means binding failed, and then there
+	 * is no point in keeping the device instantiated.
+	 */
+	if (!client->driver) {
+		i2c_unregister_device(client);
+		return -ENODEV;
+	}
 
 	/*
 	 * Let i2c-core delete that device on driver removal.
diff --git a/sound/ppc/keywest.c b/sound/ppc/keywest.c
index 835fa19..bb6819a 100644
--- a/sound/ppc/keywest.c
+++ b/sound/ppc/keywest.c
@@ -59,6 +59,18 @@ static int keywest_attach_adapter(struct i2c_adapter *adapter)
 	strlcpy(info.type, "keywest", I2C_NAME_SIZE);
 	info.addr = keywest_ctx->addr;
 	keywest_ctx->client = i2c_new_device(adapter, &info);
+	if (!keywest_ctx->client)
+		return -ENODEV;
+	/*
+	 * We know the driver is already loaded, so the device should be
+	 * already bound. If not it means binding failed, and then there
+	 * is no point in keeping the device instantiated.
+	 */
+	if (!keywest_ctx->client->driver) {
+		i2c_unregister_device(keywest_ctx->client);
+		keywest_ctx->client = NULL;
+		return -ENODEV;
+	}
 	
 	/*
 	 * Let i2c-core delete that device on driver removal.


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