Add a flag to tell wdm_read/wdm_write that a reset is in progress,
and wake any blocking read/write before taking the mutexes. This
allows the device to reset without waiting for blocking IO to
finish.
Signed-off-by: Bjørn Mork <bjorn@xxxxxxx>
---
Thought I might as well take another shot at this. Still not sure
about which error code to return from read/write.
v2: use a new dedicated flag
v3: protect reset agaings wdm_open as well
v4: back to using read/write mutexes as well as the new flag
drivers/usb/class/cdc-wdm.c | 21 +++++++++++++++++----
1 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index f63601a..b27bbb9 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -70,6 +70,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids);
#define WDM_POLL_RUNNING 6
#define WDM_RESPONDING 7
#define WDM_SUSPENDING 8
+#define WDM_RESETTING 9
#define WDM_MAX 16
@@ -340,6 +341,10 @@ static ssize_t wdm_write
else
if (test_bit(WDM_IN_USE, &desc->flags))
r = -EAGAIN;
+
+ if (test_bit(WDM_RESETTING, &desc->flags))
+ r = -EIO;
+
if (r < 0) {
kfree(buf);
goto out;
@@ -419,6 +424,10 @@ retry:
rv = -ENODEV;
goto err;
}
+ if (test_bit(WDM_RESETTING, &desc->flags)) {
+ rv = -EIO;
+ goto err;
+ }
usb_mark_last_busy(interface_to_usbdev(desc->intf));
if (rv < 0) {
rv = -ERESTARTSYS;
@@ -859,10 +868,6 @@ static int wdm_pre_reset(struct usb_interface *intf)
{
struct wdm_device *desc = usb_get_intfdata(intf);
- mutex_lock(&desc->rlock);
- mutex_lock(&desc->wlock);
- kill_urbs(desc);
-
/*
* we notify everybody using poll of
* an exceptional situation
@@ -870,9 +875,16 @@ static int wdm_pre_reset(struct usb_interface *intf)
* message from the device is lost
*/
spin_lock_irq(&desc->iuspin);
+ set_bit(WDM_RESETTING, &desc->flags); /* inform read/write */
+ set_bit(WDM_READ, &desc->flags); /* unblock read */
+ clear_bit(WDM_IN_USE, &desc->flags); /* unblock write */
desc->rerr = -EINTR;
spin_unlock_irq(&desc->iuspin);
wake_up_all(&desc->wait);
+ mutex_lock(&desc->rlock);
+ mutex_lock(&desc->wlock);
+ kill_urbs(desc);
+ cancel_work_sync(&desc->rxwork);
return 0;
}
@@ -881,6 +893,7 @@ static int wdm_post_reset(struct usb_interface *intf)
struct wdm_device *desc = usb_get_intfdata(intf);
int rv;
+ clear_bit(WDM_RESETTING, &desc->flags);
rv = recover_from_urb_loss(desc);
mutex_unlock(&desc->wlock);
mutex_unlock(&desc->rlock);
--
1.7.8.3
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