From e47db94e10447fc467777a40302f2b393e9af2fa Mon Sep 17 00:00:00 2001 From: "santosh.shilimkar@oracle.com" Date: Thu, 14 Apr 2016 10:43:27 -0700 Subject: [PATCH] RDS: Fix the atomicity for congestion map update Two different threads with different rds sockets may be in rds_recv_rcvbuf_delta() via receive path. If their ports both map to the same word in the congestion map, then using non-atomic ops to update it could cause the map to be incorrect. Lets use atomics to avoid such an issue. Full credit to Wengang for finding the issue, analysing it and also pointing out to offending code with spin lock based fix. Reviewed-by: Leon Romanovsky Signed-off-by: Wengang Wang Signed-off-by: Santosh Shilimkar Signed-off-by: David S. Miller --- net/rds/cong.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/rds/cong.c b/net/rds/cong.c index e6144b8..6641bcf 100644 --- a/net/rds/cong.c +++ b/net/rds/cong.c @@ -299,7 +299,7 @@ void rds_cong_set_bit(struct rds_cong_map *map, __be16 port) i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - __set_bit_le(off, (void *)map->m_page_addrs[i]); + set_bit_le(off, (void *)map->m_page_addrs[i]); } void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port) @@ -313,7 +313,7 @@ void rds_cong_clear_bit(struct rds_cong_map *map, __be16 port) i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS; off = be16_to_cpu(port) % RDS_CONG_MAP_PAGE_BITS; - __clear_bit_le(off, (void *)map->m_page_addrs[i]); + clear_bit_le(off, (void *)map->m_page_addrs[i]); } static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port) -- 2.7.4