From d986294ee55d719562b20aabe15a39bf8f863415 Mon Sep 17 00:00:00 2001
From: Suwan Kim <suwan.kim027@gmail.com>
Date: Fri, 13 Dec 2019 11:30:54 +0900
Subject: [PATCH] usbip: Fix receive error in vhci-hcd when using scatter-gather
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Git-commit: d986294ee55d719562b20aabe15a39bf8f863415
Patch-mainline: v5.5-rc3
References: bsc#1051510

When vhci uses SG and receives data whose size is smaller than SG
buffer size, it tries to receive more data even if it acutally
receives all the data from the server. If then, it erroneously adds
error event and triggers connection shutdown.

vhci-hcd should check if it received all the data even if there are
more SG entries left. So, check if it receivces all the data from
the server in for_each_sg() loop.

Fixes: ea44d190764b ("usbip: Implement SG support to vhci-hcd and stub driver")
Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Suwan Kim <suwan.kim027@gmail.com>
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191213023055.19933-2-suwan.kim027@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/usbip/usbip_common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
index 6532d68e8808..e4b96674c405 100644
--- a/drivers/usb/usbip/usbip_common.c
+++ b/drivers/usb/usbip/usbip_common.c
@@ -727,6 +727,9 @@ int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb)
 
 			copy -= recv;
 			ret += recv;
+
+			if (!copy)
+				break;
 		}
 
 		if (ret != size)
-- 
2.16.4