Upon receipt of the NETDEV_REGISTER event from the netdev notifier chain, the IB stack registration is spawned off to a workqueue since that also requires an rtnl lock. There could be 2 kinds of races between the NETDEV_REGISTER and the NETDEV_UNREGISTER event handling. a)The NETDEV_UNREGISTER event is received in rapid succession after the NETDEV_REGISTER event even before the work queue got a chance to run. b)The NETDEV_UNREGISTER event is received while the workqueue that handles registration with the IB stack is still in progress. Handle both the races with a bit flag that is set just before the work item is queued and cleared in the workqueue after the event is handled just before the workqueue item is freed. Signed-off-by: Somnath Kotur <somnath.kotur@xxxxxxxxxxxx> --- drivers/infiniband/hw/bnxt_re/bnxt_re.h | 12 +++++++----- drivers/infiniband/hw/bnxt_re/main.c | 8 ++++++++ 2 files changed, 15 insertions(+), 5 deletions(-) diff --git a/drivers/infiniband/hw/bnxt_re/bnxt_re.h b/drivers/infiniband/hw/bnxt_re/bnxt_re.h index b3ad37f..a25f9d2 100644 --- a/drivers/infiniband/hw/bnxt_re/bnxt_re.h +++ b/drivers/infiniband/hw/bnxt_re/bnxt_re.h @@ -93,11 +93,13 @@ struct bnxt_re_dev { struct ib_device ibdev; struct list_head list; unsigned long flags; -#define BNXT_RE_FLAG_NETDEV_REGISTERED 0 -#define BNXT_RE_FLAG_IBDEV_REGISTERED 1 -#define BNXT_RE_FLAG_GOT_MSIX 2 -#define BNXT_RE_FLAG_RCFW_CHANNEL_EN 8 -#define BNXT_RE_FLAG_QOS_WORK_REG 16 +#define BNXT_RE_FLAG_NETDEV_REGISTERED 0 +#define BNXT_RE_FLAG_IBDEV_REGISTERED 1 +#define BNXT_RE_FLAG_GOT_MSIX 2 +#define BNXT_RE_FLAG_HAVE_L2_REF 3 +#define BNXT_RE_FLAG_RCFW_CHANNEL_EN 4 +#define BNXT_RE_FLAG_QOS_WORK_REG 5 +#define BNXT_RE_FLAG_TASK_IN_PROG 6 struct net_device *netdev; unsigned int version, major, minor; struct bnxt_en_dev *en_dev; diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c index 00a3b74..29c3d7e 100644 --- a/drivers/infiniband/hw/bnxt_re/main.c +++ b/drivers/infiniband/hw/bnxt_re/main.c @@ -1259,6 +1259,8 @@ static void bnxt_re_task(struct work_struct *work) default: break; } + smp_mb__before_atomic(); + clear_bit(BNXT_RE_FLAG_TASK_IN_PROG, &rdev->flags); kfree(re_work); } @@ -1317,6 +1319,11 @@ static int bnxt_re_netdev_event(struct notifier_block *notifier, break; case NETDEV_UNREGISTER: + /* netdev notifier will call NETDEV_UNREGISTER again later since + * we are still holding the reference to the netdev + */ + if (test_bit(BNXT_RE_FLAG_TASK_IN_PROG, &rdev->flags)) + goto exit; bnxt_re_ib_unreg(rdev, false); bnxt_re_remove_one(rdev); bnxt_re_dev_unreg(rdev); @@ -1335,6 +1342,7 @@ static int bnxt_re_netdev_event(struct notifier_block *notifier, re_work->vlan_dev = (real_dev == netdev ? NULL : netdev); INIT_WORK(&re_work->work, bnxt_re_task); + set_bit(BNXT_RE_FLAG_TASK_IN_PROG, &rdev->flags); queue_work(bnxt_re_wq, &re_work->work); } } -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html