rds: memory leak in __rds_conn_create()

mainline inclusion
from mainline-v5.16-rc6
commit 5f9562eb
bugzilla: 185989 https://gitee.com/openeuler/kernel/issues/I4DDEL
CVE: CVE-2021-45480

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5f9562ebe710c307adc5f666bf1a2162ee7977c0



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__rds_conn_create() did not release conn->c_path when loop_trans != 0 and
trans->t_prefer_loopback != 0 and is_outgoing == 0.

Fixes: aced3ce5 ("RDS tcp loopback connection can hang")
Signed-off-by: Hangyu Hua <hbh25y@gmail.com>
Reviewed-by: Sharath Srinivasan <sharath.srinivasan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Baisong Zhong <zhongbaisong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>