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From:   Suwan Kim <suwan.kim027@gmail.com>
To:     shuah@kernel.org, valentina.manea.m@gmail.com,
        gregkh@linuxfoundation.org, marmarek@invisiblethingslab.com
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org, stern@rowland.harvard.edu,
        Suwan Kim <suwan.kim027@gmail.com>
Subject: [PATCH v2 1/2] usbip: Fix receive error in vhci-hcd when using scatter-gather
Date:   Fri, 13 Dec 2019 11:30:54 +0900
Message-Id: <20191213023055.19933-2-suwan.kim027@gmail.com>
In-Reply-To: <20191213023055.19933-1-suwan.kim027@gmail.com>
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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>
---
 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)
-- 
2.20.1