ksmbd: fix read on the uninitialized send_ctx

mainline inclusion
from mainline-5.15-rc1
commit b8fc94cd
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I60T7G
CVE: NA

Reference: https://git.kernel.org/torvalds/linux/c/b8fc94cdb144

-------------------------------

If st->status is not SMB_DIRECT_CS_CONNECTED, It will jump done label
and accessing the uninitialized send_ctxi by smb_direct_flush_send_list
will cause kernel oops. This patch just return -ENOTCONN to avoid it.
Reported-by: NCoverity Scan <scan-admin@coverity.com>
Signed-off-by: NNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: NSteve French <stfrench@microsoft.com>
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NZhong Jinghua <zhongjinghua@huawei.com>

fs/ksmbd/transport_rdma.c

@@ -1207,10 +1207,8 @@ static int smb_direct_writev(struct ksmbd_transport *t,
 	struct kvec vec;
 	struct smb_direct_send_ctx send_ctx;
 
-	if (st->status != SMB_DIRECT_CS_CONNECTED) {
-		ret = -ENOTCONN;
-		goto done;
-	}
+	if (st->status != SMB_DIRECT_CS_CONNECTED)
+		return -ENOTCONN;
 
 	//FIXME: skip RFC1002 header..
 	buflen -= 4;