[PATCH v4] usbnet/cdc_ncm: Don't use stack variables for DMA

[Josh Boyer]

The cdc_ncm driver still has a few places where stack variables are
passed to the cdc_ncm_do_request function.  This triggers a stack trace in
lib/dma-debug.c if the CONFIG_DEBUG_DMA_API option is set.

Adjust these calls to pass parameters that have been allocated with
kzalloc.

Signed-off-by: Josh Boyer <jwboyer@xxxxxxxxxx>
---
v4: Rebase against 3.1-rc1
v3: Fix checkpatch errors
v2: Fix leak in error path

 drivers/net/usb/cdc_ncm.c |   47 ++++++++++++++++++++++++++++++++++++--------
 1 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index a03336e..f06fb78 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -228,23 +228,40 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 	if (ctx->rx_max != le32_to_cpu(ctx->ncm_parm.dwNtbInMaxSize)) {
 
 		if (flags & USB_CDC_NCM_NCAP_NTB_INPUT_SIZE) {
-			struct usb_cdc_ncm_ndp_input_size ndp_in_sz;
+			struct usb_cdc_ncm_ndp_input_size *ndp_in_sz;
+
+			ndp_in_sz = kzalloc(sizeof(*ndp_in_sz), GFP_KERNEL);
+			if (!ndp_in_sz) {
+				err = -ENOMEM;
+				goto size_err;
+			}
+
 			err = usb_control_msg(ctx->udev,
 					usb_sndctrlpipe(ctx->udev, 0),
 					USB_CDC_SET_NTB_INPUT_SIZE,
 					USB_TYPE_CLASS | USB_DIR_OUT
 					 | USB_RECIP_INTERFACE,
-					0, iface_no, &ndp_in_sz, 8, 1000);
+					0, iface_no, ndp_in_sz, 8, 1000);
+			kfree(ndp_in_sz);
 		} else {
-			__le32 dwNtbInMaxSize = cpu_to_le32(ctx->rx_max);
+			__le32 *dwNtbInMaxSize;
+			dwNtbInMaxSize = kzalloc(sizeof(*dwNtbInMaxSize),
+					GFP_KERNEL);
+			if (!dwNtbInMaxSize) {
+				err = -ENOMEM;
+				goto size_err;
+			}
+			*dwNtbInMaxSize = cpu_to_le32(ctx->rx_max);
+
 			err = usb_control_msg(ctx->udev,
 					usb_sndctrlpipe(ctx->udev, 0),
 					USB_CDC_SET_NTB_INPUT_SIZE,
 					USB_TYPE_CLASS | USB_DIR_OUT
 					 | USB_RECIP_INTERFACE,
-					0, iface_no, &dwNtbInMaxSize, 4, 1000);
+					0, iface_no, dwNtbInMaxSize, 4, 1000);
+			kfree(dwNtbInMaxSize);
 		}
-
+size_err:
 		if (err < 0)
 			pr_debug("Setting NTB Input Size failed\n");
 	}
@@ -325,19 +342,29 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 
 	/* set Max Datagram Size (MTU) */
 	if (flags & USB_CDC_NCM_NCAP_MAX_DATAGRAM_SIZE) {
-		__le16 max_datagram_size;
+		__le16 *max_datagram_size;
 		u16 eth_max_sz = le16_to_cpu(ctx->ether_desc->wMaxSegmentSize);
+
+		max_datagram_size = kzalloc(sizeof(*max_datagram_size),
+				GFP_KERNEL);
+		if (!max_datagram_size) {
+			err = -ENOMEM;
+			goto max_dgram_err;
+		}
+
 		err = usb_control_msg(ctx->udev, usb_rcvctrlpipe(ctx->udev, 0),
 				USB_CDC_GET_MAX_DATAGRAM_SIZE,
 				USB_TYPE_CLASS | USB_DIR_IN
 				 | USB_RECIP_INTERFACE,
-				0, iface_no, &max_datagram_size,
+				0, iface_no, max_datagram_size,
 				2, 1000);
 		if (err < 0) {
 			pr_debug("GET_MAX_DATAGRAM_SIZE failed, use size=%u\n",
 						CDC_NCM_MIN_DATAGRAM_SIZE);
+			kfree(max_datagram_size);
 		} else {
-			ctx->max_datagram_size = le16_to_cpu(max_datagram_size);
+			ctx->max_datagram_size =
+				le16_to_cpu(*max_datagram_size);
 			/* Check Eth descriptor value */
 			if (eth_max_sz < CDC_NCM_MAX_DATAGRAM_SIZE) {
 				if (ctx->max_datagram_size > eth_max_sz)
@@ -360,8 +387,10 @@ static u8 cdc_ncm_setup(struct cdc_ncm_ctx *ctx)
 						USB_TYPE_CLASS | USB_DIR_OUT
 						 | USB_RECIP_INTERFACE,
 						0,
-						iface_no, &max_datagram_size,
+						iface_no, max_datagram_size,
 						2, 1000);
+			kfree(max_datagram_size);
+max_dgram_err:
 			if (err < 0)
 				pr_debug("SET_MAX_DATAGRAM_SIZE failed\n");
 		}
--
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