redonkable/remarkable-linux
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HID: remove setup mutex, fix possible deadlock

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It causes recursive locking warning and is unneeded after
introduction of STARTED flag.

* Resume vs. stop is effectively solved by DISCONNECT flag.
* No problem in suspend vs. start -- urb is submitted even after open
  which is possible after connect which is called after start.
* Resume vs. start solved by STARTED flag.
* Suspend vs. stop -- no problem in killing urb and timer twice.

Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Jiri Slaby 2008-11-23 12:03:20 +01:00 committed by Jiri Kosina
parent 578f3a35fe
commit fde5be353e
2 changed files with 2 additions and 17 deletions
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18
drivers/hid/usbhid/hid-core.c
View file

@ -796,7 +796,6 @@ static int usbhid_start(struct hid_device *hid)
if (insize > HID_MAX_BUFFER_SIZE)
insize = HID_MAX_BUFFER_SIZE;
mutex_lock(&usbhid->setup);
if (hid_alloc_buffers(dev, hid)) {
ret = -ENOMEM;
goto fail;
@ -876,7 +875,6 @@ static int usbhid_start(struct hid_device *hid)
hid_dump_device(hid);
set_bit(HID_STARTED, &usbhid->iofl);
mutex_unlock(&usbhid->setup);
return 0;
@ -888,7 +886,6 @@ fail:
usbhid->urbout = NULL;
usbhid->urbctrl = NULL;
hid_free_buffers(dev, hid);
mutex_unlock(&usbhid->setup);
return ret;
}
@ -899,7 +896,6 @@ static void usbhid_stop(struct hid_device *hid)
if (WARN_ON(!usbhid))
return;
mutex_lock(&usbhid->setup);
clear_bit(HID_STARTED, &usbhid->iofl);
spin_lock_irq(&usbhid->inlock); /* Sync with error handler */
set_bit(HID_DISCONNECTED, &usbhid->iofl);
@ -928,7 +924,6 @@ static void usbhid_stop(struct hid_device *hid)
usbhid->urbout = NULL;
hid_free_buffers(hid_to_usb_dev(hid), hid);
mutex_unlock(&usbhid->setup);
}
static struct hid_ll_driver usb_hid_driver = {
@ -1016,7 +1011,6 @@ static int hid_probe(struct usb_interface *intf, const struct usb_device_id *id)
hid->driver_data = usbhid;
usbhid->hid = hid;
mutex_init(&usbhid->setup); /* needed on suspend/resume */
ret = hid_add_device(hid);
if (ret) {
@ -1051,18 +1045,14 @@ static int hid_suspend(struct usb_interface *intf, pm_message_t message)
struct hid_device *hid = usb_get_intfdata (intf);
struct usbhid_device *usbhid = hid->driver_data;
mutex_lock(&usbhid->setup);
if (!test_bit(HID_STARTED, &usbhid->iofl)) {
mutex_unlock(&usbhid->setup);
if (!test_bit(HID_STARTED, &usbhid->iofl))
return 0;
}
spin_lock_irq(&usbhid->inlock); /* Sync with error handler */
set_bit(HID_SUSPENDED, &usbhid->iofl);
spin_unlock_irq(&usbhid->inlock);
del_timer_sync(&usbhid->io_retry);
usb_kill_urb(usbhid->urbin);
mutex_unlock(&usbhid->setup);
dev_dbg(&intf->dev, "suspend\n");
return 0;
}
@ -1073,16 +1063,12 @@ static int hid_resume(struct usb_interface *intf)
struct usbhid_device *usbhid = hid->driver_data;
int status;
mutex_lock(&usbhid->setup);
if (!test_bit(HID_STARTED, &usbhid->iofl)) {
mutex_unlock(&usbhid->setup);
if (!test_bit(HID_STARTED, &usbhid->iofl))
return 0;
}
clear_bit(HID_SUSPENDED, &usbhid->iofl);
usbhid->retry_delay = 0;
status = hid_start_in(hid);
mutex_unlock(&usbhid->setup);
dev_dbg(&intf->dev, "resume status %d\n", status);
return status;
}

1
drivers/hid/usbhid/usbhid.h
View file

@ -74,7 +74,6 @@ struct usbhid_device {
dma_addr_t outbuf_dma; /* Output buffer dma */
spinlock_t outlock; /* Output fifo spinlock */
struct mutex setup;
unsigned long iofl; /* I/O flags (CTRL_RUNNING, OUT_RUNNING) */
struct timer_list io_retry; /* Retry timer */
unsigned long stop_retry; /* Time to give up, in jiffies */