rds: Fix spelling mistakes

Fix some spelling mistakes in comments:
alloced ==> allocated

Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Reviewed-by: Håkon Bugge <haakon.bugge@oracle.com>
Link: https://lore.kernel.org/r/20210531063617.3018637-1-zhengyongjun3@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

RDS/IW+IB: Set recv ring low water mark to 1/2 full.

Currently the recv ring low water mark is 1/4 the depth. Performance
measurements show that this limits iWARP throughput by flow controlling
the rds-stress senders. Setting it to 1/2 seems to max the T3
performance. I tried even higher levels but that didn't help and it
started to increase the rds thread cpu utilization.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

RDS/IB: Ring-handling code.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>