From 934da4635c2d05cef474e5243ef05df95b2ad264 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Wed, 6 Aug 2008 18:44:12 -0700 Subject: usb: cdc-acm: stop dropping tx buffers The "increase cdc-acm write throughput" patch left in place two now-obsolete mechanisms, either of which can make the cdc-acm driver drop TX data (nasty!). This patch removes them: - The write_ready flag ... if an URB and buffer were found, they can (and should!) always be used. - TX path acm_wb_is_used() ... used when the buffer was just allocated, so that check is pointless. Also fix a won't-yet-matter leak of a write buffer on a disconnect path. Signed-off-by: David Brownell Cc: David Engraf Acked-by: Oliver Neukum Signed-off-by: Greg Kroah-Hartman --- drivers/usb/class/cdc-acm.h | 2 -- 1 file changed, 2 deletions(-) (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 85c3aaaab7c5..94266362ca68 100644 --- a/drivers/usb/class/cdc-acm.h +++ b/drivers/usb/class/cdc-acm.h @@ -106,8 +106,6 @@ struct acm { struct list_head spare_read_bufs; struct list_head filled_read_bufs; int write_used; /* number of non-empty write buffers */ - int write_ready; /* write urb is not running */ - int old_ready; int processing; int transmitting; spinlock_t write_lock; -- cgit v1.2.3 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 v1.2.3