[RFC][PATCH v2] usb: gadget: rndis: Free the response queue during REMOTE_NDIS_RESET_MSG

[Amit Pundir]

From: xerox_lin <xerox_lin@xxxxxxx>

When rndis data transfer is in progress, some Windows7 Host PC is not
sending the GET_ENCAPSULATED_RESPONSE command for receiving the response
for the previous SEND_ENCAPSULATED_COMMAND processed.

The rndis function driver appends each response for the
SEND_ENCAPSULATED_COMMAND in a queue. As the above process got corrupted,
the Host sends a REMOTE_NDIS_RESET_MSG command to do a soft-reset.
As the rndis response queue is not freed, the previous response is sent
as a part of this REMOTE_NDIS_RESET_MSG's reset response and the Host
blocks any more Rndis transfers.

Hence free the rndis response queue as a part of this soft-reset so that
the current response for REMOTE_NDIS_RESET_MSG is sent properly during the
response command.

Cc: Felipe Balbi <balbi@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
Cc: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>
Cc: Android Kernel Team <kernel-team@xxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Sumit Semwal <sumit.semwal@xxxxxxxxxx>
Signed-off-by: Rajkumar Raghupathy <raghup@xxxxxxxxxxxxxx>
Signed-off-by: Xerox Lin <xerox_lin@xxxxxxx>
[pundir:
 * cherry-picked this patch from AOSP experimental/android-4.4 tree.
 * folded in the AOSP fix to use rndis_params instead of configNr.]
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
---
v2: Use rndis_params instead of configNr in v1. Updated commit log.

v1: Cherry-picked this patch from AOSP common/experimental/android-4.4 tree.
    I could not find upstream submission history for this patch, so my
    apologies in advance if this has already been NACKed before.

 drivers/usb/gadget/function/rndis.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c
index 70d3917..27163e8 100644
--- a/drivers/usb/gadget/function/rndis.c
+++ b/drivers/usb/gadget/function/rndis.c
@@ -681,6 +681,13 @@ static int rndis_reset_response(struct rndis_params *params,
 	rndis_reset_cmplt_type *resp;
 	rndis_resp_t *r;
 
+	u32 length;
+	u8 *xbuf;
+
+	/* drain the response queue */
+	while ((xbuf = rndis_get_next_response(params, &length)))
+		rndis_free_response(params, xbuf);
+
 	r = rndis_add_response(params, sizeof(rndis_reset_cmplt_type));
 	if (!r)
 		return -ENOMEM;
-- 
1.9.1