diff options
| -rw-r--r-- | net/rds/ib.c | 27 | ||||
| -rw-r--r-- | net/rds/ib.h | 1 | ||||
| -rw-r--r-- | net/rds/ib_rdma.c | 8 |
3 files changed, 26 insertions, 10 deletions
diff --git a/net/rds/ib.c b/net/rds/ib.c index 3eb5617649c..b12a3951167 100644 --- a/net/rds/ib.c +++ b/net/rds/ib.c @@ -53,6 +53,12 @@ MODULE_PARM_DESC(fmr_message_size, " Max size of a RDMA transfer"); module_param(rds_ib_retry_count, int, 0444); MODULE_PARM_DESC(rds_ib_retry_count, " Number of hw retries before reporting an error"); +/* + * we have a clumsy combination of RCU and a rwsem protecting this list + * because it is used both in the get_mr fast path and while blocking in + * the FMR flushing path. + */ +DECLARE_RWSEM(rds_ib_devices_lock); struct list_head rds_ib_devices; /* NOTE: if also grabbing ibdev lock, grab this first */ @@ -171,7 +177,10 @@ void rds_ib_add_one(struct ib_device *device) INIT_LIST_HEAD(&rds_ibdev->ipaddr_list); INIT_LIST_HEAD(&rds_ibdev->conn_list); - list_add_tail(&rds_ibdev->list, &rds_ib_devices); + + down_write(&rds_ib_devices_lock); + list_add_tail_rcu(&rds_ibdev->list, &rds_ib_devices); + up_write(&rds_ib_devices_lock); atomic_inc(&rds_ibdev->refcount); ib_set_client_data(device, &rds_ib_client, rds_ibdev); @@ -230,16 +239,20 @@ void rds_ib_remove_one(struct ib_device *device) rds_ib_dev_shutdown(rds_ibdev); + /* stop connection attempts from getting a reference to this device. */ + ib_set_client_data(device, &rds_ib_client, NULL); + + down_write(&rds_ib_devices_lock); + list_del_rcu(&rds_ibdev->list); + up_write(&rds_ib_devices_lock); + /* - * prevent future connection attempts from getting a reference to this - * device and wait for currently racing connection attempts to finish - * getting their reference + * This synchronize rcu is waiting for readers of both the ib + * client data and the devices list to finish before we drop + * both of those references. */ - ib_set_client_data(device, &rds_ib_client, NULL); synchronize_rcu(); rds_ib_dev_put(rds_ibdev); - - list_del(&rds_ibdev->list); rds_ib_dev_put(rds_ibdev); } diff --git a/net/rds/ib.h b/net/rds/ib.h index a13ced50414..2189fd47a73 100644 --- a/net/rds/ib.h +++ b/net/rds/ib.h @@ -23,6 +23,7 @@ #define RDS_IB_RECYCLE_BATCH_COUNT 32 +extern struct rw_semaphore rds_ib_devices_lock; extern struct list_head rds_ib_devices; /* diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c index 0017964f2fc..8f6e221c9f7 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, |