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usb: hub: rename hub_events() to hub_event() and handle only one even…
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…t there

We would like to convert khubd kthread to a workqueue. As a result hub_events()
will handle only one event per call.

In fact, we could do this already now because there is another cycle in
hub_thread(). It calls hub_events() until hub_event_list is empty.

This patch renames the function to hub_event(), removes the while cycle, and
renames the goto targets from loop* to out*.

When touching the code, it fixes also formatting of dev_err() and dev_dbg()
calls to make checkpatch.pl happy :-)

Signed-off-by: Petr Mladek <[email protected]>
Acked-by: Alan Stern <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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@pmladek @gregkh
pmladek authored and gregkh committed Sep 24, 2014
1 parent 5d14f32 commit eb6e292
Showing 1 changed file with 111 additions and 125 deletions.
236 changes: 111 additions & 125 deletions drivers/usb/core/hub.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4996,8 +4996,7 @@ static void port_event(struct usb_hub *hub, int port1)
hub_port_connect_change(hub, port1, portstatus, portchange);
}


static void hub_events(void)
static void hub_event(void)
{
struct list_head *tmp;
struct usb_device *hdev;
Expand All @@ -5008,144 +5007,131 @@ static void hub_events(void)
u16 hubchange;
int i, ret;

/*
* We restart the list every time to avoid a deadlock with
* deleting hubs downstream from this one. This should be
* safe since we delete the hub from the event list.
* Not the most efficient, but avoids deadlocks.
*/
while (1) {
/* Grab the first entry at the beginning of the list */
spin_lock_irq(&hub_event_lock);
if (list_empty(&hub_event_list)) {
spin_unlock_irq(&hub_event_lock);
return;
}

/* Grab the first entry at the beginning of the list */
spin_lock_irq(&hub_event_lock);
if (list_empty(&hub_event_list)) {
spin_unlock_irq(&hub_event_lock);
break;
}
tmp = hub_event_list.next;
list_del_init(tmp);

tmp = hub_event_list.next;
list_del_init(tmp);
hub = list_entry(tmp, struct usb_hub, event_list);
kref_get(&hub->kref);
spin_unlock_irq(&hub_event_lock);

hub = list_entry(tmp, struct usb_hub, event_list);
kref_get(&hub->kref);
spin_unlock_irq(&hub_event_lock);
hdev = hub->hdev;
hub_dev = hub->intfdev;
intf = to_usb_interface(hub_dev);
dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
hdev->state, hdev->maxchild,
/* NOTE: expects max 15 ports... */
(u16) hub->change_bits[0],
(u16) hub->event_bits[0]);

/* Lock the device, then check to see if we were
* disconnected while waiting for the lock to succeed. */
usb_lock_device(hdev);
if (unlikely(hub->disconnected))
goto out_disconnected;

/* If the hub has died, clean up after it */
if (hdev->state == USB_STATE_NOTATTACHED) {
hub->error = -ENODEV;
hub_quiesce(hub, HUB_DISCONNECT);
goto out;
}

/* Autoresume */
ret = usb_autopm_get_interface(intf);
if (ret) {
dev_dbg(hub_dev, "Can't autoresume: %d\n", ret);
goto out;
}

hdev = hub->hdev;
hub_dev = hub->intfdev;
intf = to_usb_interface(hub_dev);
dev_dbg(hub_dev, "state %d ports %d chg %04x evt %04x\n",
hdev->state, hdev->maxchild,
/* NOTE: expects max 15 ports... */
(u16) hub->change_bits[0],
(u16) hub->event_bits[0]);

/* Lock the device, then check to see if we were
* disconnected while waiting for the lock to succeed. */
usb_lock_device(hdev);
if (unlikely(hub->disconnected))
goto loop_disconnected;

/* If the hub has died, clean up after it */
if (hdev->state == USB_STATE_NOTATTACHED) {
hub->error = -ENODEV;
hub_quiesce(hub, HUB_DISCONNECT);
goto loop;
}
/* If this is an inactive hub, do nothing */
if (hub->quiescing)
goto out_autopm;

if (hub->error) {
dev_dbg(hub_dev, "resetting for error %d\n", hub->error);

/* Autoresume */
ret = usb_autopm_get_interface(intf);
ret = usb_reset_device(hdev);
if (ret) {
dev_dbg(hub_dev, "Can't autoresume: %d\n", ret);
goto loop;
dev_dbg(hub_dev, "error resetting hub: %d\n", ret);
goto out_autopm;
}

/* If this is an inactive hub, do nothing */
if (hub->quiescing)
goto loop_autopm;
hub->nerrors = 0;
hub->error = 0;
}

if (hub->error) {
dev_dbg (hub_dev, "resetting for error %d\n",
hub->error);
/* deal with port status changes */
for (i = 1; i <= hdev->maxchild; i++) {
struct usb_port *port_dev = hub->ports[i - 1];

ret = usb_reset_device(hdev);
if (ret) {
dev_dbg (hub_dev,
"error resetting hub: %d\n", ret);
goto loop_autopm;
}

hub->nerrors = 0;
hub->error = 0;
if (test_bit(i, hub->event_bits)
|| test_bit(i, hub->change_bits)
|| test_bit(i, hub->wakeup_bits)) {
/*
* The get_noresume and barrier ensure that if
* the port was in the process of resuming, we
* flush that work and keep the port active for
* the duration of the port_event(). However,
* if the port is runtime pm suspended
* (powered-off), we leave it in that state, run
* an abbreviated port_event(), and move on.
*/
pm_runtime_get_noresume(&port_dev->dev);
pm_runtime_barrier(&port_dev->dev);
usb_lock_port(port_dev);
port_event(hub, i);
usb_unlock_port(port_dev);
pm_runtime_put_sync(&port_dev->dev);
}
}

/* deal with port status changes */
for (i = 1; i <= hdev->maxchild; i++) {
struct usb_port *port_dev = hub->ports[i - 1];

if (test_bit(i, hub->event_bits)
|| test_bit(i, hub->change_bits)
|| test_bit(i, hub->wakeup_bits)) {
/*
* The get_noresume and barrier ensure that if
* the port was in the process of resuming, we
* flush that work and keep the port active for
* the duration of the port_event(). However,
* if the port is runtime pm suspended
* (powered-off), we leave it in that state, run
* an abbreviated port_event(), and move on.
*/
pm_runtime_get_noresume(&port_dev->dev);
pm_runtime_barrier(&port_dev->dev);
usb_lock_port(port_dev);
port_event(hub, i);
usb_unlock_port(port_dev);
pm_runtime_put_sync(&port_dev->dev);
}
/* deal with hub status changes */
if (test_and_clear_bit(0, hub->event_bits) == 0)
; /* do nothing */
else if (hub_hub_status(hub, &hubstatus, &hubchange) < 0)
dev_err(hub_dev, "get_hub_status failed\n");
else {
if (hubchange & HUB_CHANGE_LOCAL_POWER) {
dev_dbg(hub_dev, "power change\n");
clear_hub_feature(hdev, C_HUB_LOCAL_POWER);
if (hubstatus & HUB_STATUS_LOCAL_POWER)
/* FIXME: Is this always true? */
hub->limited_power = 1;
else
hub->limited_power = 0;
}
if (hubchange & HUB_CHANGE_OVERCURRENT) {
u16 status = 0;
u16 unused;

/* deal with hub status changes */
if (test_and_clear_bit(0, hub->event_bits) == 0)
; /* do nothing */
else if (hub_hub_status(hub, &hubstatus, &hubchange) < 0)
dev_err (hub_dev, "get_hub_status failed\n");
else {
if (hubchange & HUB_CHANGE_LOCAL_POWER) {
dev_dbg (hub_dev, "power change\n");
clear_hub_feature(hdev, C_HUB_LOCAL_POWER);
if (hubstatus & HUB_STATUS_LOCAL_POWER)
/* FIXME: Is this always true? */
hub->limited_power = 1;
else
hub->limited_power = 0;
}
if (hubchange & HUB_CHANGE_OVERCURRENT) {
u16 status = 0;
u16 unused;

dev_dbg(hub_dev, "over-current change\n");
clear_hub_feature(hdev, C_HUB_OVER_CURRENT);
msleep(500); /* Cool down */
hub_power_on(hub, true);
hub_hub_status(hub, &status, &unused);
if (status & HUB_STATUS_OVERCURRENT)
dev_err(hub_dev, "over-current "
"condition\n");
}
dev_dbg(hub_dev, "over-current change\n");
clear_hub_feature(hdev, C_HUB_OVER_CURRENT);
msleep(500); /* Cool down */
hub_power_on(hub, true);
hub_hub_status(hub, &status, &unused);
if (status & HUB_STATUS_OVERCURRENT)
dev_err(hub_dev, "over-current condition\n");
}
}

loop_autopm:
/* Balance the usb_autopm_get_interface() above */
usb_autopm_put_interface_no_suspend(intf);
loop:
/* Balance the usb_autopm_get_interface_no_resume() in
* kick_khubd() and allow autosuspend.
*/
usb_autopm_put_interface(intf);
loop_disconnected:
usb_unlock_device(hdev);
kref_put(&hub->kref, hub_release);

} /* end while (1) */
out_autopm:
/* Balance the usb_autopm_get_interface() above */
usb_autopm_put_interface_no_suspend(intf);
out:
/* Balance the usb_autopm_get_interface_no_resume() in
* kick_khubd() and allow autosuspend.
*/
usb_autopm_put_interface(intf);
out_disconnected:
usb_unlock_device(hdev);
kref_put(&hub->kref, hub_release);
}

static int hub_thread(void *__unused)
Expand All @@ -5158,7 +5144,7 @@ static int hub_thread(void *__unused)
set_freezable();

do {
hub_events();
hub_event();
wait_event_freezable(khubd_wait,
!list_empty(&hub_event_list) ||
kthread_should_stop());
Expand Down

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