This patch reduces number of event handling threads to one.
In existing implementation, event kernel threads are created for each
port. The functions of the threads are terminationg connection and
error handling. It's too expensive to have to each port.
With this patch, event handler is a single thread workqueue
[usbip_event].
Both application (vhci) and device (stub) side are replaced.
Signed-off-by: Nobuo Iwata <nobuo.iw...@fujixerox.co.jp>
---
drivers/usb/usbip/stub_dev.c | 3 +-
drivers/usb/usbip/usbip_common.c | 7 ++
drivers/usb/usbip/usbip_common.h | 4 +-
drivers/usb/usbip/usbip_event.c | 174 +++++++++++++++++++++++--------
4 files changed, 141 insertions(+), 47 deletions(-)
diff --git a/drivers/usb/usbip/stub_dev.c b/drivers/usb/usbip/stub_dev.c
index d8d3add..9ec002d 100644
--- a/drivers/usb/usbip/stub_dev.c
+++ b/drivers/usb/usbip/stub_dev.c
@@ -380,7 +380,6 @@ err_files:
err_port:
dev_set_drvdata(&udev->dev, NULL);
usb_put_dev(udev);
- kthread_stop_put(sdev->ud.eh);
busid_priv->sdev = NULL;
stub_device_free(sdev);
@@ -441,7 +440,7 @@ static void stub_disconnect(struct usb_device *udev)
}
/* If usb reset is called from event handler */
- if (busid_priv->sdev->ud.eh == current)
+ if (usbip_in_eh(current))
return;
/* shutdown the current connection */
diff --git a/drivers/usb/usbip/usbip_common.c b/drivers/usb/usbip/usbip_common.c
index 963d8db..8c9fb19 100644
--- a/drivers/usb/usbip/usbip_common.c
+++ b/drivers/usb/usbip/usbip_common.c
@@ -807,12 +807,19 @@ EXPORT_SYMBOL_GPL(usbip_trx_ops);
static int __init usbip_core_init(void)
{
+ int ret;
+
pr_info(DRIVER_DESC " v" USBIP_VERSION "\n");
+ ret = usbip_init_eh();
+ if (ret) {
+ return ret;
+ }
return 0;
}
static void __exit usbip_core_exit(void)
{
+ usbip_finish_eh();
return;
}
diff --git a/drivers/usb/usbip/usbip_common.h b/drivers/usb/usbip/usbip_common.h
index 33b470c..0c72ecb 100644
--- a/drivers/usb/usbip/usbip_common.h
+++ b/drivers/usb/usbip/usbip_common.h
@@ -275,7 +275,6 @@ struct usbip_device {
struct task_struct *tcp_tx;
unsigned long event;
- struct task_struct *eh;
wait_queue_head_t eh_waitq;
struct eh_ops {
@@ -321,10 +320,13 @@ void usbip_pad_iso(struct usbip_device *ud, struct urb
*urb);
int usbip_recv_xbuff(struct usbip_device *ud, struct urb *urb);
/* usbip_event.c */
+int usbip_init_eh(void);
+void usbip_finish_eh(void);
int usbip_start_eh(struct usbip_device *ud);
void usbip_stop_eh(struct usbip_device *ud);
void usbip_event_add(struct usbip_device *ud, unsigned long event);
int usbip_event_happened(struct usbip_device *ud);
+int usbip_in_eh(struct task_struct *task);
static inline int interface_to_busnum(struct usb_interface *interface)
{
diff --git a/drivers/usb/usbip/usbip_event.c b/drivers/usb/usbip/usbip_event.c
index 64933b9..22cb4d8 100644
--- a/drivers/usb/usbip/usbip_event.c
+++ b/drivers/usb/usbip/usbip_event.c
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2003-2008 Takahiro Hirofuchi
+ * Copyright (C) 2015 Nobuo Iwata
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -19,17 +20,68 @@
#include <linux/kthread.h>
#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
#include "usbip_common.h"
-static int event_handler(struct usbip_device *ud)
+struct usbip_event {
+ struct list_head node;
+ struct usbip_device *ud;
+};
+
+static DEFINE_SPINLOCK(event_lock);
+static LIST_HEAD(event_list);
+
+void set_event(struct usbip_device *ud, unsigned long event)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ud->lock, flags);
+ ud->event |= event;
+ spin_unlock_irqrestore(&ud->lock, flags);
+}
+
+void unset_event(struct usbip_device *ud, unsigned long event)
{
- usbip_dbg_eh("enter\n");
+ unsigned long flags;
+
+ spin_lock_irqsave(&ud->lock, flags);
+ ud->event &= ~event;
+ spin_unlock_irqrestore(&ud->lock, flags);
+}
+
+static struct usbip_device *get_event(void)
+{
+ struct usbip_event *ue = NULL;
+ struct usbip_device *ud = NULL;
+ unsigned long flags;
- /*
- * Events are handled by only this thread.
- */
- while (usbip_event_happened(ud)) {
+ spin_lock_irqsave(&event_lock, flags);
+ if (!list_empty(&event_list)) {
+ ue = list_first_entry(&event_list, struct usbip_event, node);
+ list_del(&ue->node);
+ }
+ spin_unlock_irqrestore(&event_lock, flags);
+
+ if (ue) {
+ ud = ue->ud;
+ kfree(ue);
+ }
+ return ud;
+}
+
+struct task_struct *worker_context = NULL;
+
+static void event_handler(struct work_struct *work)
+{
+ struct usbip_device *ud;
+
+ if (worker_context == NULL) {
+ worker_context = current;
+ }
+
+ while ((ud = get_event()) != NULL) {
usbip_dbg_eh("pending event %lx\n", ud->event);
/*
@@ -38,79 +90,104 @@ static int event_handler(struct usbip_device *ud)
*/
if (ud->event & USBIP_EH_SHUTDOWN) {
ud->eh_ops.shutdown(ud);
- ud->event &= ~USBIP_EH_SHUTDOWN;
+ unset_event(ud, USBIP_EH_SHUTDOWN);
}
/* Reset the device. */
if (ud->event & USBIP_EH_RESET) {
ud->eh_ops.reset(ud);
- ud->event &= ~USBIP_EH_RESET;
+ unset_event(ud, USBIP_EH_RESET);
}
/* Mark the device as unusable. */
if (ud->event & USBIP_EH_UNUSABLE) {
ud->eh_ops.unusable(ud);
- ud->event &= ~USBIP_EH_UNUSABLE;
+ unset_event(ud, USBIP_EH_UNUSABLE);
}
/* Stop the error handler. */
- if (ud->event & USBIP_EH_BYE)
- return -1;
- }
-
- return 0;
-}
-
-static int event_handler_loop(void *data)
-{
- struct usbip_device *ud = data;
-
- while (!kthread_should_stop()) {
- wait_event_interruptible(ud->eh_waitq,
- usbip_event_happened(ud) ||
- kthread_should_stop());
- usbip_dbg_eh("wakeup\n");
+ if (ud->event & USBIP_EH_BYE) {
+ usbip_dbg_eh("removed %p\n", ud);
+ }
- if (event_handler(ud) < 0)
- break;
+ wake_up(&ud->eh_waitq);
}
-
- return 0;
}
int usbip_start_eh(struct usbip_device *ud)
{
init_waitqueue_head(&ud->eh_waitq);
ud->event = 0;
-
- ud->eh = kthread_run(event_handler_loop, ud, "usbip_eh");
- if (IS_ERR(ud->eh)) {
- pr_warn("Unable to start control thread\n");
- return PTR_ERR(ud->eh);
- }
-
return 0;
}
EXPORT_SYMBOL_GPL(usbip_start_eh);
void usbip_stop_eh(struct usbip_device *ud)
{
- if (ud->eh == current)
- return; /* do not wait for myself */
+ unsigned long pending = ud->event & ~USBIP_EH_BYE;
- kthread_stop(ud->eh);
- usbip_dbg_eh("usbip_eh has finished\n");
+ if (!(ud->event & USBIP_EH_BYE)) {
+ usbip_dbg_eh("usbip_eh stopping but not removed\n");
+ }
+ if (pending) {
+ usbip_dbg_eh("usbip_eh waiting completion %lx\n", pending);
+ }
+ wait_event_interruptible(ud->eh_waitq, !(ud->event & ~USBIP_EH_BYE));
+ usbip_dbg_eh("usbip_eh has stopped\n");
}
EXPORT_SYMBOL_GPL(usbip_stop_eh);
+#define WORK_QUEUE_NAME "usbip_event"
+struct workqueue_struct *usbip_queue = NULL;
+static DECLARE_WORK(usbip_work, event_handler);
+
+int usbip_init_eh(void)
+{
+ usbip_queue = create_singlethread_workqueue(WORK_QUEUE_NAME);
+ if (usbip_queue == NULL) {
+ pr_err("failed to create usbip_event\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+void usbip_finish_eh(void)
+{
+ flush_workqueue(usbip_queue);
+ destroy_workqueue(usbip_queue);
+ usbip_queue = NULL;
+}
+
void usbip_event_add(struct usbip_device *ud, unsigned long event)
{
+ struct usbip_event *ue;
unsigned long flags;
- spin_lock_irqsave(&ud->lock, flags);
- ud->event |= event;
- wake_up(&ud->eh_waitq);
- spin_unlock_irqrestore(&ud->lock, flags);
+ if (ud->event & USBIP_EH_BYE) {
+ return;
+ }
+ set_event(ud, event);
+
+ spin_lock_irqsave(&event_lock, flags);
+
+ list_for_each_entry_reverse(ue, &event_list, node) {
+ if (ue->ud == ud) {
+ goto out;
+ }
+ }
+
+ ue = kmalloc(sizeof(struct usbip_event), GFP_ATOMIC);
+ if (ue == NULL) {
+ pr_err("failed to alloc event\n");
+ goto out;
+ }
+ ue->ud = ud;
+
+ list_add_tail(&ue->node, &event_list);
+ queue_work(usbip_queue, &usbip_work);
+
+out:
+ spin_unlock_irqrestore(&event_lock, flags);
}
EXPORT_SYMBOL_GPL(usbip_event_add);
@@ -126,3 +203,12 @@ int usbip_event_happened(struct usbip_device *ud)
return happened;
}
EXPORT_SYMBOL_GPL(usbip_event_happened);
+
+int usbip_in_eh(struct task_struct *task)
+{
+ if (task == worker_context) {
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usbip_in_eh);
--
2.1.0
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