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RDS: Fix the atomicity for congestion map update

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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 <wen.gang.wang@oracle.com> for
finding the issue, analysing it and also pointing out
to offending code with spin lock based fix.

Reviewed-by: Leon Romanovsky <leon@leon.nu>
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
santosh.shilimkar@oracle.com 2016-04-14 10:43:27 -07:00 committed by David S. Miller
parent a7c556546f
commit e47db94e10
1 changed files with 2 additions and 2 deletions
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4
net/rds/cong.c
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@ -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; i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
off = 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) 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; i = be16_to_cpu(port) / RDS_CONG_MAP_PAGE_BITS;
off = 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) static int rds_cong_test_bit(struct rds_cong_map *map, __be16 port)