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Commit 885281cc authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: usblp: fix DMA to stack 



commit 020a1f453449294926ca548d8d5ca970926e8dfd upstream.

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@vger.kernel.org
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210104145302.2087-1-johan@kernel.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 49bb1069

drivers/usb/class/usblp.c

+19 −2
Original line number Original line Diff line number Diff line
@@ -289,8 +289,25 @@ static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, i 
#define usblp_reset(usblp)\

#define usblp_reset(usblp)\

	usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)

	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) \

static int usblp_hp_channel_change_request(struct usblp *usblp, int channel, u8 *new_channel)

	usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)

{

	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

 * See the description for usblp_select_alts() below for the usage