David Miller [davem@xxxxxxxxxxxxx] > This is racey. > If another thread of control sets the bit between the test and the > clear, you will lose an event. It is fine. The flag is used to schedule a tasklet, so if the tasklet is starting running, all the other plans for scheduling a tasklet could be cleared. Besides, the flag is only set when a transmission occurs and the device is in autosuspend mode. Then the workqueue could wake up the device and schedule the tasklet to make sure the tasklet wouldn't be run when the device is in suspend mode. Therefore, if the tasklet is running, it means something happens and the device is waked up. And the queue for scheduling the tasklet is unnecessary. We don't need the tasklet runs again after current one except that the relative tx/rx flows schedule it. > It really never makes sense to work with atomic bitops in a non-atomic > test-and-whatever manner like this, it's always a red flag and > indicates you're doing something very wrong. I use atomic because I don't wish the different threads which set the different flags would chang the other bits which they don't interesting in. Best Regards, Hayes -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
