misc: rtsx_usb: use separate command and response buffers

rtsx_usb uses same buffer for command and response. There could
be a potential conflict using the same buffer for both especially
if retries and timeouts are involved.

Use separate command and response buffers to avoid conflicts.

Signed-off-by: Shuah Khan <[e-mail]>
Cc: stable <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/misc/cardreader/rtsx_usb.c

···
 
 	ucr->pusb_dev = usb_dev;
 
-	ucr->iobuf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
-	if (!ucr->iobuf)
+	ucr->cmd_buf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
+	if (!ucr->cmd_buf)
 		return -ENOMEM;
+
+	ucr->rsp_buf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
+	if (!ucr->rsp_buf)
+		goto out_free_cmd_buf;
 
 	usb_set_intfdata(intf, ucr);
 
 	ucr->vendor_id = id->idVendor;
 	ucr->product_id = id->idProduct;
-	ucr->cmd_buf = ucr->rsp_buf = ucr->iobuf;
 
 	mutex_init(&ucr->dev_mutex);
 
···
 
 out_init_fail:
 	usb_set_intfdata(ucr->pusb_intf, NULL);
-	kfree(ucr->iobuf);
-	ucr->iobuf = NULL;
-	ucr->cmd_buf = ucr->rsp_buf = NULL;
+	kfree(ucr->rsp_buf);
+	ucr->rsp_buf = NULL;
+out_free_cmd_buf:
+	kfree(ucr->cmd_buf);
+	ucr->cmd_buf = NULL;
 	return ret;
 }
 
···
 	mfd_remove_devices(&intf->dev);
 
 	usb_set_intfdata(ucr->pusb_intf, NULL);
-	kfree(ucr->iobuf);
-	ucr->iobuf = NULL;
-	ucr->cmd_buf = ucr->rsp_buf = NULL;
+
+	kfree(ucr->cmd_buf);
+	ucr->cmd_buf = NULL;
+
+	kfree(ucr->rsp_buf);
+	ucr->rsp_buf = NULL;
 }
 
 #ifdef CONFIG_PM

include/linux/rtsx_usb.h

···
 	struct usb_device	*pusb_dev;
 	struct usb_interface	*pusb_intf;
 	struct usb_sg_request	current_sg;
-	unsigned char		*iobuf;
 
 	struct timer_list	sg_timer;
 	struct mutex		dev_mutex;