[PATCH] usb: gadget: eem: fix command packet transfer issue

[<linyyuan@codeaurora.org>]

From: Linyu Yuan <linyyuan@codeaurora.com>

there is following warning,
[<ffffff8008905a94>] dwc3_gadget_ep_queue+0x1b4/0x1c8
[<ffffff800895ec9c>] usb_ep_queue+0x3c/0x120
[<ffffff80089677a0>] eem_unwrap+0x180/0x330
[<ffffff80089634f8>] rx_complete+0x70/0x230
[<ffffff800895edbc>] usb_gadget_giveback_request+0x3c/0xe8
[<ffffff8008901e7c>] dwc3_gadget_giveback+0xb4/0x190
[<ffffff8008905254>] dwc3_endpoint_transfer_complete+0x32c/0x410
[<ffffff80089060fc>] dwc3_bh_work+0x654/0x12e8
[<ffffff80080c63fc>] process_one_work+0x1d4/0x4a8
[<ffffff80080c6720>] worker_thread+0x50/0x4a8
[<ffffff80080cc8e8>] kthread+0xe8/0x100
[<ffffff8008083980>] ret_from_fork+0x10/0x50
request ffffffc0716bf200 belongs to 'ep0out'

when gadget receive a eem command packet from host, it need to response,
but queue usb request to wrong endpoint.
fix it by queue usb request to eem IN endpoint and allow host read it.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Linyu Yuan <linyyuan@codeaurora.org>
---
 drivers/usb/gadget/function/f_eem.c | 44
++++++++++++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/function/f_eem.c
b/drivers/usb/gadget/function/f_eem.c
index 2cd9942..2c2ca1e 100644
--- a/drivers/usb/gadget/function/f_eem.c
+++ b/drivers/usb/gadget/function/f_eem.c
@@ -30,6 +30,11 @@ struct f_eem {
 	u8				ctrl_id;
 };
 
+struct in_context {
+	struct sk_buff	*skb;
+	struct usb_ep	*ep;
+};
+
 static inline struct f_eem *func_to_eem(struct usb_function *f)
 {
 	return container_of(f, struct f_eem, port.func);
@@ -320,9 +325,12 @@ static int eem_bind(struct usb_configuration *c, struct
usb_function *f)
 
 static void eem_cmd_complete(struct usb_ep *ep, struct usb_request *req)
 {
-	struct sk_buff *skb = (struct sk_buff *)req->context;
+	struct in_context *ctx = req->context;
 
-	dev_kfree_skb_any(skb);
+	kfree(req->buf);
+	dev_kfree_skb_any(ctx->skb);
+	usb_ep_free_request(ctx->ep, req);
+	kfree(ctx);
 }
 
 /*
@@ -410,7 +418,9 @@ static int eem_unwrap(struct gether *port,
 		 * b15:		bmType (0 == data, 1 == command)
 		 */
 		if (header & BIT(15)) {
-			struct usb_request	*req = cdev->req;
+			struct usb_request	*req;
+			struct in_context	*ctx;
+			struct usb_ep		*ep;
 			u16			bmEEMCmd;
 
 			/* EEM command packet format:
@@ -439,13 +449,37 @@ static int eem_unwrap(struct gether *port,
 				skb_trim(skb2, len);
 				put_unaligned_le16(BIT(15) | BIT(11) | len,
 							skb_push(skb2, 2));
+
+				ep = port->in_ep;
+				req = usb_ep_alloc_request(ep, GFP_ATOMIC);
+				if (!req) {
+					dev_kfree_skb_any(skb2);
+					break;
+				}
+
+				ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+				if (!ctx)
+					goto nomem;
+				ctx->skb = skb2;
+				ctx->ep = ep;
+
+				req->buf = kmalloc(skb2->len, GFP_KERNEL);
+				if (!req->buf)
+					goto nomem;
+
 				skb_copy_bits(skb2, 0, req->buf, skb2->len);
 				req->length = skb2->len;
 				req->complete = eem_cmd_complete;
 				req->zero = 1;
-				req->context = skb2;
-				if (usb_ep_queue(port->in_ep, req,
GFP_ATOMIC))
+				req->context = ctx;
+				if (usb_ep_queue(ep, req, GFP_ATOMIC)) {
 					DBG(cdev, "echo response queue
fail\n");
+nomem:
+					kfree(req->buf);
+					usb_ep_free_request(ep, req);
+					dev_kfree_skb_any(skb2);
+					kfree(ctx);
+				}
 				break;
 
 			case 1:  /* echo response */
-- 
2.7.4