From c936f45fc25fd53c1517571aa379e07bca1f28ed Mon Sep 17 00:00:00 2001 From: Bhaktipriya Shridhar Date: Tue, 26 Jul 2016 10:47:20 +0530 Subject: [PATCH] usb: ftdi-elan: Remove deprecated create_singlethread_workqueue The status workqueue is involved in initializing the Uxxx and polling the Uxxx until a supported PCMCIA CardBus device is detected. It then starts the command and respond workqueues and then loads the module that handles the device, after which it just polls the Uxxx looking for card ejects. The command and respond workqueues are involved in implementing a command sequencer for communicating with the firmware on the other side of the FTDI chip in the Uxxx. These workqueues have only a single work item each and hence they do not require ordering. Also, none of the above workqueues are being used on a memory recliam path. Hence, the singlethreaded workqueues have been replaced with the use of system_wq. System workqueues have been able to handle high level of concurrency for a long time now and hence it's not required to have a singlethreaded workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue created with create_singlethread_workqueue(), system_wq allows multiple work items to overlap executions even on the same CPU; however, a per-cpu workqueue doesn't have any CPU locality or global ordering guarantee unless the target CPU is explicitly specified and thus the increase of local concurrency shouldn't make any difference. The work items have been sync cancelled because they are self-requeueing and need to wait for the in-flight work item to finish before proceeding with destruction. Hence, they have been sync cancelled in ftdi_status_cancel_work(), ftdi_command_cancel_work() and ftdi_response_cancel_work(). These functions are called in ftdi_elan_exit() to ensure that there are no pending work items while disconnecting the driver. Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- drivers/usb/misc/ftdi-elan.c | 53 +++++++----------------------------- 1 file changed, 10 insertions(+), 43 deletions(-) diff --git a/drivers/usb/misc/ftdi-elan.c b/drivers/usb/misc/ftdi-elan.c index 52c27cab78c3..59031dc21eab 100644 --- a/drivers/usb/misc/ftdi-elan.c +++ b/drivers/usb/misc/ftdi-elan.c @@ -61,9 +61,6 @@ module_param(distrust_firmware, bool, 0); MODULE_PARM_DESC(distrust_firmware, "true to distrust firmware power/overcurrent setup"); extern struct platform_driver u132_platform_driver; -static struct workqueue_struct *status_queue; -static struct workqueue_struct *command_queue; -static struct workqueue_struct *respond_queue; /* * ftdi_module_lock exists to protect access to global variables * @@ -228,56 +225,56 @@ static void ftdi_elan_init_kref(struct usb_ftdi *ftdi) static void ftdi_status_requeue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (!queue_delayed_work(status_queue, &ftdi->status_work, delta)) + if (!schedule_delayed_work(&ftdi->status_work, delta)) kref_put(&ftdi->kref, ftdi_elan_delete); } static void ftdi_status_queue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (queue_delayed_work(status_queue, &ftdi->status_work, delta)) + if (schedule_delayed_work(&ftdi->status_work, delta)) kref_get(&ftdi->kref); } static void ftdi_status_cancel_work(struct usb_ftdi *ftdi) { - if (cancel_delayed_work(&ftdi->status_work)) + if (cancel_delayed_work_sync(&ftdi->status_work)) kref_put(&ftdi->kref, ftdi_elan_delete); } static void ftdi_command_requeue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (!queue_delayed_work(command_queue, &ftdi->command_work, delta)) + if (!schedule_delayed_work(&ftdi->command_work, delta)) kref_put(&ftdi->kref, ftdi_elan_delete); } static void ftdi_command_queue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (queue_delayed_work(command_queue, &ftdi->command_work, delta)) + if (schedule_delayed_work(&ftdi->command_work, delta)) kref_get(&ftdi->kref); } static void ftdi_command_cancel_work(struct usb_ftdi *ftdi) { - if (cancel_delayed_work(&ftdi->command_work)) + if (cancel_delayed_work_sync(&ftdi->command_work)) kref_put(&ftdi->kref, ftdi_elan_delete); } static void ftdi_response_requeue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (!queue_delayed_work(respond_queue, &ftdi->respond_work, delta)) + if (!schedule_delayed_work(&ftdi->respond_work, delta)) kref_put(&ftdi->kref, ftdi_elan_delete); } static void ftdi_respond_queue_work(struct usb_ftdi *ftdi, unsigned int delta) { - if (queue_delayed_work(respond_queue, &ftdi->respond_work, delta)) + if (schedule_delayed_work(&ftdi->respond_work, delta)) kref_get(&ftdi->kref); } static void ftdi_response_cancel_work(struct usb_ftdi *ftdi) { - if (cancel_delayed_work(&ftdi->respond_work)) + if (cancel_delayed_work_sync(&ftdi->respond_work)) kref_put(&ftdi->kref, ftdi_elan_delete); } @@ -2823,9 +2820,6 @@ static void ftdi_elan_disconnect(struct usb_interface *interface) ftdi->initialized = 0; ftdi->registered = 0; } - flush_workqueue(status_queue); - flush_workqueue(command_queue); - flush_workqueue(respond_queue); ftdi->disconnected += 1; usb_set_intfdata(interface, NULL); dev_info(&ftdi->udev->dev, "USB FTDI U132 host controller interface now disconnected\n"); @@ -2845,31 +2839,12 @@ static int __init ftdi_elan_init(void) pr_info("driver %s\n", ftdi_elan_driver.name); mutex_init(&ftdi_module_lock); INIT_LIST_HEAD(&ftdi_static_list); - status_queue = create_singlethread_workqueue("ftdi-status-control"); - if (!status_queue) - goto err_status_queue; - command_queue = create_singlethread_workqueue("ftdi-command-engine"); - if (!command_queue) - goto err_command_queue; - respond_queue = create_singlethread_workqueue("ftdi-respond-engine"); - if (!respond_queue) - goto err_respond_queue; result = usb_register(&ftdi_elan_driver); if (result) { - destroy_workqueue(status_queue); - destroy_workqueue(command_queue); - destroy_workqueue(respond_queue); pr_err("usb_register failed. Error number %d\n", result); } return result; -err_respond_queue: - destroy_workqueue(command_queue); -err_command_queue: - destroy_workqueue(status_queue); -err_status_queue: - pr_err("%s couldn't create workqueue\n", ftdi_elan_driver.name); - return -ENOMEM; } static void __exit ftdi_elan_exit(void) @@ -2882,15 +2857,7 @@ static void __exit ftdi_elan_exit(void) ftdi_status_cancel_work(ftdi); ftdi_command_cancel_work(ftdi); ftdi_response_cancel_work(ftdi); - } flush_workqueue(status_queue); - destroy_workqueue(status_queue); - status_queue = NULL; - flush_workqueue(command_queue); - destroy_workqueue(command_queue); - command_queue = NULL; - flush_workqueue(respond_queue); - destroy_workqueue(respond_queue); - respond_queue = NULL; + } }