Stack-allocated buffers cannot be used for DMA (on all architectures).
Replace the HP-channel macro with a helper function that allocates a
dedicated transfer buffer so that it can continue to be used with
arguments from the stack.
Note that the buffer is cleared on allocation as usblp_ctrl_msg()
returns success also on short transfers (the buffer is only used for
debugging).
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
---
drivers/usb/class/usblp.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 67cbd42421be..134dc2005ce9 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -274,8 +274,25 @@ static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, i
#define usblp_reset(usblp)\
usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)
-#define usblp_hp_channel_change_request(usblp, channel, buffer) \
- usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)
+static int usblp_hp_channel_change_request(struct usblp *usblp, int channel, u8 *new_channel)
+{
+ u8 *buf;
+ int ret;
+
+ buf = kzalloc(1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ ret = usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST,
+ USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE,
+ channel, buf, 1);
+ if (ret == 0)
+ *new_channel = buf[0];
+
+ kfree(buf);
+
+ return ret;
+}
/*
* See the description for usblp_select_alts() below for the usage
--
2.26.2
