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 <dbrownell@users.sourceforge.net>
Cc:  David Engraf <david.engraf@netcom.eu>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 0 insertions, 2 deletions

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;