From e5fbab51b4219fbd1dab28666affe38a920b5f7e Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 6 Aug 2008 18:46:10 -0700 Subject: usb: cdc-acm: drain writes on close Add a mechanism to let the write queue drain naturally before closing the TTY, rather than always losing that data. There is a timeout, so it can't wait too long. Provide missing locking inside acm_wb_is_avail(); it matters more now. Note, this presumes an earlier patch was applied, removing a call to this routine where the lock was held. Slightly improved diagnostics on write URB completion, so we can tell when a write URB gets killed and, if so, how much data it wrote first ... and so that I/O path is normally silent (and can't much change timings). Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/usb/class/cdc-acm.h') diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h index 94266362ca68..1f95e7aa1b66 100644 --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -113,6 +113,7 @@ struct acm { struct usb_cdc_line_coding line; /* bits, stop, parity */ struct work_struct work; /* work queue entry for line discipline waking up */ struct work_struct waker; + wait_queue_head_t drain_wait; /* close processing */ struct tasklet_struct urb_task; /* rx processing */ spinlock_t throttle_lock; /* synchronize throtteling and read callback */ unsigned int ctrlin; /* input control lines (DCD, DSR, RI, break, overruns) */ -- cgit v1.2.1