i2c: smbus: kill memory leak on emulated and failed DMA SMBus xfers

If DMA safe memory was allocated, but the subsequent I2C transfer
fails the memory is leaked. Plug this leak.

Fixes: 8a77821e74d6 ("i2c: smbus: use DMA safe buffers for emulated SMBus transactions")
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org
(cherry picked from commit 9aa613674f89d01248ae2e4afe691b515ff8fbb6)
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
index 60b1ee2..663173d 100644
--- a/drivers/i2c/i2c-core-smbus.c
+++ b/drivers/i2c/i2c-core-smbus.c
@@ -460,15 +460,18 @@
 
 	status = i2c_transfer(adapter, msg, num);
 	if (status < 0)
-		return status;
-	if (status != num)
-		return -EIO;
+		goto cleanup;
+	if (status != num) {
+		status = -EIO;
+		goto cleanup;
+	}
+	status = 0;
 
 	/* Check PEC if last message is a read */
 	if (i && (msg[num-1].flags & I2C_M_RD)) {
 		status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
 		if (status < 0)
-			return status;
+			goto cleanup;
 	}
 
 	if (read_write == I2C_SMBUS_READ)
@@ -494,12 +497,13 @@
 			break;
 		}
 
+cleanup:
 	if (msg[0].flags & I2C_M_DMA_SAFE)
 		kfree(msg[0].buf);
 	if (msg[1].flags & I2C_M_DMA_SAFE)
 		kfree(msg[1].buf);
 
-	return 0;
+	return status;
 }
 
 /**