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USB: usblp: fix DMA to stack 

commit 020a1f4534 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: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210104145302.2087-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Johan Hovold 2021-01-04 15:53:02 +01:00 committed by Greg Kroah-Hartman
parent 41f15da2ab
commit 5c263f1682
1 changed files with 19 additions and 2 deletions
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21
drivers/usb/class/usblp.c
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@ -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