From 4249d6fbc10fd997abdf8a1ea49c0389a0edf706 Mon Sep 17 00:00:00 2001
From: Linyu Yuan <linyyuan@codeaurora.com>
Date: Wed, 16 Jun 2021 19:51:42 +0800
Subject: [PATCH] usb: gadget: eem: fix echo command packet response issue
Git-commit: 4249d6fbc10fd997abdf8a1ea49c0389a0edf706
Patch-mainline: v5.14-rc1
References: git-fixes

when receive eem echo command, it will send a response,
but queue this response to the usb request which allocate
from gadget device endpoint zero,
and transmit the request to IN endpoint of eem interface.

on dwc3 gadget, it will trigger following warning in function
__dwc3_gadget_ep_queue(),

	if (WARN(req->dep != dep, "request %pK belongs to '%s'\n",
				&req->request, req->dep->name))
		return -EINVAL;

fix it by allocating a usb request from IN endpoint of eem interface,
and transmit the usb request to same IN endpoint of eem interface.

Signed-off-by: Linyu Yuan <linyyuan@codeaurora.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210616115142.34075-1-linyyuan@codeaurora.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/gadget/function/f_eem.c | 43 ++++++++++++++++++++++++++---
 1 file changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/function/f_eem.c b/drivers/usb/gadget/function/f_eem.c
index 2cd9942707b4..5d38f29bda72 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);
+	dev_kfree_skb_any(ctx->skb);
+	kfree(req->buf);
+	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:
@@ -439,11 +449,36 @@ 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);
+					goto next;
+				}
+
+				req->buf = kmalloc(skb2->len, GFP_KERNEL);
+				if (!req->buf) {
+					usb_ep_free_request(ep, req);
+					dev_kfree_skb_any(skb2);
+					goto next;
+				}
+
+				ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+				if (!ctx) {
+					kfree(req->buf);
+					usb_ep_free_request(ep, req);
+					dev_kfree_skb_any(skb2);
+					goto next;
+				}
+				ctx->skb = skb2;
+				ctx->ep = ep;
+
 				skb_copy_bits(skb2, 0, req->buf, skb2->len);
 				req->length = skb2->len;
 				req->complete = eem_cmd_complete;
 				req->zero = 1;
-				req->context = skb2;
+				req->context = ctx;
 				if (usb_ep_queue(port->in_ep, req, GFP_ATOMIC))
 					DBG(cdev, "echo response queue fail\n");
 				break;
-- 
2.26.2