Comment 0 for bug 1764982

Hi
Machine stuck after unregistering bonding interface when the nvmet_rdma module is loading.

scenario:

 # modprobe nvmet_rdma
 # modprobe -r bonding
 # modprobe bonding -v mode=1 miimon=100 fail_over_mac=0
 # ifdown eth4
 # ifdown eth5
 # ip addr add 15.209.12.173/8 dev bond0
 # ip link set bond0 up
 # echo +eth5 > /sys/class/net/bond0/bonding/slaves
 # echo +eth4 > /sys/class/net/bond0/bonding/slaves
 # echo -eth4 > /sys/class/net/bond0/bonding/slaves
 # echo -eth5 > /sys/class/net/bond0/bonding/slaves
 # echo -bond0 > /sys/class/net/bonding_masters

dmesg:

kernel: [78348.225556] bond0 (unregistering): Released all slaves
kernel: [78358.339631] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78368.419621] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78378.499615] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78388.579625] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78398.659613] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78408.739655] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78418.819634] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78428.899642] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78438.979614] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78449.059619] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78459.139626] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78469.219623] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78479.299619] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78489.379620] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78499.459623] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78509.539631] unregister_netdevice: waiting for bond0 to become free. Usage count = 2
kernel: [78519.619629] unregister_netdevice: waiting for bond0 to become free. Usage count = 2

The following upstream commits that fix this issue

commit a3dd7d0022c347207ae931c753a6dc3e6e8fcbc1
Author: Max Gurtovoy <email address hidden>
Date: Wed Feb 28 13:12:38 2018 +0200

    nvmet-rdma: Don't flush system_wq by default during remove_one

    The .remove_one function is called for any ib_device removal.
    In case the removed device has no reference in our driver, there
    is no need to flush the system work queue.

    Reviewed-by: Israel Rukshin <email address hidden>
    Signed-off-by: Max Gurtovoy <email address hidden>
    Reviewed-by: Sagi Grimberg <email address hidden>
    Signed-off-by: Keith Busch <email address hidden>
    Signed-off-by: Jens Axboe <email address hidden>

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index aa8068f..a59263d 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -1469,8 +1469,25 @@ static struct nvmet_fabrics_ops nvmet_rdma_ops = {
 static void nvmet_rdma_remove_one(struct ib_device *ib_device, void *client_data)
 {
        struct nvmet_rdma_queue *queue, *tmp;
+ struct nvmet_rdma_device *ndev;
+ bool found = false;
+
+ mutex_lock(&device_list_mutex);
+ list_for_each_entry(ndev, &device_list, entry) {
+ if (ndev->device == ib_device) {
+ found = true;
+ break;
+ }
+ }
+ mutex_unlock(&device_list_mutex);
+
+ if (!found)
+ return;

- /* Device is being removed, delete all queues using this device */
+ /*
+ * IB Device that is used by nvmet controllers is being removed,
+ * delete all queues using this device.
+ */
        mutex_lock(&nvmet_rdma_queue_mutex);
        list_for_each_entry_safe(queue, tmp, &nvmet_rdma_queue_list,
                                 queue_list) {

commit 9bad0404ecd7594265cef04e176adeaa4ffbca4a
Author: Max Gurtovoy <email address hidden>
Date: Wed Feb 28 13:12:39 2018 +0200

    nvme-rdma: Don't flush delete_wq by default during remove_one

    The .remove_one function is called for any ib_device removal.
    In case the removed device has no reference in our driver, there
    is no need to flush the work queue.

    Reviewed-by: Israel Rukshin <email address hidden>
    Signed-off-by: Max Gurtovoy <email address hidden>
    Reviewed-by: Sagi Grimberg <email address hidden>
    Signed-off-by: Keith Busch <email address hidden>
    Signed-off-by: Jens Axboe <email address hidden>

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index f5f460b..250b277 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -2024,6 +2024,20 @@ static struct nvmf_transport_ops nvme_rdma_transport = {
 static void nvme_rdma_remove_one(struct ib_device *ib_device, void *client_data)
 {
        struct nvme_rdma_ctrl *ctrl;
+ struct nvme_rdma_device *ndev;
+ bool found = false;
+
+ mutex_lock(&device_list_mutex);
+ list_for_each_entry(ndev, &device_list, entry) {
+ if (ndev->dev == ib_device) {
+ found = true;
+ break;
+ }
+ }
+ mutex_unlock(&device_list_mutex);
+
+ if (!found)
+ return;

        /* Delete all controllers using this device */
        mutex_lock(&nvme_rdma_ctrl_mutex);