mwifex: free rx_cmd skb in suspended state

USB suspend handler will kill the presubmitted rx_cmd URB. This
triggers a call to the corresponding URB complete handler, which
will free the rx_cmd skb, associated with rx_cmd URB. Due to a
possible race betwen suspend handler and main thread, depicted in
'commit bfcacac6c84b ("mwifiex: do no submit URB in suspended
state")', it is possible that the rx_cmd skb will fail to get
freed. This causes a memory leak, since the resume handler will
always allocate a new rx_cmd skb.

To fix this, free the rx_cmd skb in mwifiex_usb_submit_rx_urb, if
the device is in suspended state.
Signed-off-by: Vidya Dharmaraju <vidyad@marvell.com>
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Ganapathi Bhat <gbhat@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/usb.c

@@ -299,6 +299,12 @@ static int mwifiex_usb_submit_rx_urb(struct urb_context *ctx, int size)
 	struct usb_card_rec *card = (struct usb_card_rec *)adapter->card;
 
 	if (test_bit(MWIFIEX_IS_SUSPENDED, &adapter->work_flags)) {
+		if (card->rx_cmd_ep == ctx->ep) {
+			mwifiex_dbg(adapter, INFO, "%s: free rx_cmd skb\n",
+				    __func__);
+			dev_kfree_skb_any(ctx->skb);
+			ctx->skb = NULL;
+		}
 		mwifiex_dbg(adapter, ERROR,
 			    "%s: card removed/suspended, EP %d rx_cmd URB submit skipped\n",
 			    __func__, ctx->ep);