diff options
| author | Zach Brown <zach.brown@oracle.com> | 2010-07-15 12:34:33 -0700 |
|---|---|---|
| committer | Andy Grover <andy.grover@oracle.com> | 2010-09-08 18:16:44 -0700 |
| commit | ea819867b788728aca60717e4fdacb3df771f670 (patch) | |
| tree | 68952e283e4b119622c6e8244d96e41c623ae4b0 /net/rds/ib_rdma.c | |
| parent | 1bde04a63d532c2540d6fdee0a661530a62b1686 (diff) | |
| download | linux-ea819867b788728aca60717e4fdacb3df771f670.tar.bz2 | |
RDS/IB: protect the list of IB devices
The RDS IB device list wasn't protected by any locking. Traversal in
both the get_mr and FMR flushing paths could race with additon and
removal.
List manipulation is done with RCU primatives and is protected by the
write side of a rwsem. The list traversal in the get_mr fast path is
protected by a rcu read critical section. The FMR list traversal is
more problematic because it can block while traversing the list. We
protect this with the read side of the rwsem.
Signed-off-by: Zach Brown <zach.brown@oracle.com>
Diffstat (limited to 'net/rds/ib_rdma.c')
| -rw-r--r-- | net/rds/ib_rdma.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c index 0017964f2fcf..8f6e221c9f78 100644 --- a/net/rds/ib_rdma.c +++ b/net/rds/ib_rdma.c @@ -94,8 +94,8 @@ static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr) struct rds_ib_device *rds_ibdev; struct rds_ib_ipaddr *i_ipaddr; - list_for_each_entry(rds_ibdev, &rds_ib_devices, list) { - rcu_read_lock(); + rcu_read_lock(); + list_for_each_entry_rcu(rds_ibdev, &rds_ib_devices, list) { list_for_each_entry_rcu(i_ipaddr, &rds_ibdev->ipaddr_list, list) { if (i_ipaddr->ipaddr == ipaddr) { atomic_inc(&rds_ibdev->refcount); @@ -103,8 +103,8 @@ static struct rds_ib_device *rds_ib_get_device(__be32 ipaddr) return rds_ibdev; } } - rcu_read_unlock(); } + rcu_read_unlock(); return NULL; } @@ -761,12 +761,14 @@ void rds_ib_flush_mrs(void) { struct rds_ib_device *rds_ibdev; + down_read(&rds_ib_devices_lock); list_for_each_entry(rds_ibdev, &rds_ib_devices, list) { struct rds_ib_mr_pool *pool = rds_ibdev->mr_pool; if (pool) rds_ib_flush_mr_pool(pool, 0, NULL); } + up_read(&rds_ib_devices_lock); } void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents, |