[PATCH] USB: Converting cdc acm to a ring queue

this patch by David converts the sending queue of the CDC ACM driver
to a queue of URBs. This is needed for quicker devices. Please apply.

Signed-Off-By: Oliver Neukum <oliver@neukum.name>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

 drivers/usb/class/cdc-acm.c |  229 ++++++++++++++++++++++++++++++--------------
 drivers/usb/class/cdc-acm.h |   33 +++++-
 2 files changed, 185 insertions(+), 77 deletions(-)

1 files changed, 28 insertions, 5 deletions

diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 963a5dfd2096..fd2aaccdcbac 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -59,6 +59,9 @@
  * when processing onlcr, so we only need 2 buffers.
  */
 #define ACM_NWB  2
+#define ACM_NRU  16
+#define ACM_NRB  16
+
 struct acm_wb {
         unsigned char *buf;
         dma_addr_t dmah;
@@ -66,22 +69,43 @@ struct acm_wb {
         int use;
 };
 
+struct acm_rb {
+        struct list_head        list;
+        int                     size;
+        unsigned char           *base;
+        dma_addr_t              dma;
+};
+
+struct acm_ru {
+        struct list_head        list;
+        struct acm_rb           *buffer;
+        struct urb              *urb;
+        struct acm              *instance;
+};
+
 struct acm {
         struct usb_device *dev;                         /* the corresponding usb device */
         struct usb_interface *control;                  /* control interface */
         struct usb_interface *data;                     /* data interface */
         struct tty_struct *tty;                         /* the corresponding tty */
-        struct urb *ctrlurb, *readurb, *writeurb;       /* urbs */
-        u8 *ctrl_buffer, *read_buffer;                  /* buffers of urbs */
-        dma_addr_t ctrl_dma, read_dma;                  /* dma handles of buffers */
+        struct urb *ctrlurb, *writeurb;                 /* urbs */
+        u8 *ctrl_buffer;                                /* buffers of urbs */
+        dma_addr_t ctrl_dma;                            /* dma handles of buffers */
         struct acm_wb wb[ACM_NWB];
+        struct acm_ru ru[ACM_NRU];
+        struct acm_rb rb[ACM_NRB];
+        int rx_endpoint;
+        spinlock_t read_lock;
+        struct list_head spare_read_urbs;
+        struct list_head spare_read_bufs;
+        struct list_head filled_read_bufs;
         int write_current;                              /* current write buffer */
         int write_used;                                 /* number of non-empty write buffers */
         int write_ready;                                /* write urb is not running */
         spinlock_t write_lock;
         struct usb_cdc_line_coding line;                /* bits, stop, parity */
         struct work_struct work;                        /* work queue entry for line discipline waking up */
-        struct tasklet_struct bh;                       /* rx 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) */
         unsigned int ctrlout;                           /* output control lines (DTR, RTS) */
@@ -91,7 +115,6 @@ struct acm {
         unsigned int minor;                             /* acm minor number */
         unsigned char throttle;                         /* throttled by tty layer */
         unsigned char clocal;                           /* termios CLOCAL */
-        unsigned char resubmit_to_unthrottle;           /* throtteling has disabled the read urb */
         unsigned int ctrl_caps;                         /* control capabilities from the class specific header */
 };