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authorZach Brown <zach.brown@oracle.com>2010-07-15 12:34:33 -0700
committerAndy Grover <andy.grover@oracle.com>2010-09-08 18:16:44 -0700
commitea819867b788728aca60717e4fdacb3df771f670 (patch)
tree68952e283e4b119622c6e8244d96e41c623ae4b0 /net/rds/ib_rdma.c
parent1bde04a63d532c2540d6fdee0a661530a62b1686 (diff)
downloadlinux-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.c8
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,