USB: increase cdc-acm write throughput

the following patch uses 16 write urbs and a writsize of wMaxPacketSize
* 20.  With this patch I get the maximum througput from my linux system
with 20MB/sec read and 15 MB/sec write (full speed 1 MB/sec both)

I also deleted the flag URB_NO_FSBR for the writeurbs, because this
makes my full speed devices significant slower.

Signed-off-by: David Engraf <david.engraf@netcom.eu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 45 insertions, 43 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 1ded83b66af0..d9b408113921 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -31,6 +31,7 @@
  *      v0.23 - use softirq for rx processing, as needed by tty layer
  *      v0.24 - change probe method to evaluate CDC union descriptor
  *      v0.25 - downstream tasks paralelized to maximize throughput
+ *      v0.26 - multiple write urbs, writesize increased
  */
 
 /*
@@ -72,7 +73,7 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "v0.25"
+#define DRIVER_VERSION "v0.26"
 #define DRIVER_AUTHOR "Armin Fuerst, Pavel Machek, Johannes Erdfelt, Vojtech Pavlik, David Kubicek"
 #define DRIVER_DESC "USB Abstract Control Model driver for USB modems and ISDN adapters"
 
@@ -118,7 +119,7 @@ static int acm_wb_alloc(struct acm *acm)
         int i, wbn;
         struct acm_wb *wb;
 
-        wbn = acm->write_current;
+        wbn = 0;
         i = 0;
         for (;;) {
                 wb = &acm->wb[wbn];
@@ -132,11 +133,6 @@ static int acm_wb_alloc(struct acm *acm)
         }
 }
 
-static void acm_wb_free(struct acm *acm, int wbn)
-{
-        acm->wb[wbn].use = 0;
-}
-
 static int acm_wb_is_avail(struct acm *acm)
 {
         int i, n;
@@ -156,26 +152,22 @@ static inline int acm_wb_is_used(struct acm *acm, int wbn)
 /*
  * Finish write.
  */
-static void acm_write_done(struct acm *acm)
+static void acm_write_done(struct acm *acm, struct acm_wb *wb)
 {
         unsigned long flags;
-        int wbn;
 
         spin_lock_irqsave(&acm->write_lock, flags);
         acm->write_ready = 1;
-        wbn = acm->write_current;
-        acm_wb_free(acm, wbn);
-        acm->write_current = (wbn + 1) % ACM_NW;
+        wb->use = 0;
         spin_unlock_irqrestore(&acm->write_lock, flags);
 }
 
 /*
  * Poke write.
  */
-static int acm_write_start(struct acm *acm)
+static int acm_write_start(struct acm *acm, int wbn)
 {
         unsigned long flags;
-        int wbn;
         struct acm_wb *wb;
         int rc;
 
@@ -190,24 +182,24 @@ static int acm_write_start(struct acm *acm)
                 return 0;       /* A white lie */
         }
 
-        wbn = acm->write_current;
         if (!acm_wb_is_used(acm, wbn)) {
                 spin_unlock_irqrestore(&acm->write_lock, flags);
                 return 0;
         }
         wb = &acm->wb[wbn];
 
-        acm->write_ready = 0;
+        if(acm_wb_is_avail(acm) <= 1)
+                acm->write_ready = 0;
         spin_unlock_irqrestore(&acm->write_lock, flags);
 
-        acm->writeurb->transfer_buffer = wb->buf;
-        acm->writeurb->transfer_dma = wb->dmah;
-        acm->writeurb->transfer_buffer_length = wb->len;
-        acm->writeurb->dev = acm->dev;
+        wb->urb->transfer_buffer = wb->buf;
+        wb->urb->transfer_dma = wb->dmah;
+        wb->urb->transfer_buffer_length = wb->len;
+        wb->urb->dev = acm->dev;
 
-        if ((rc = usb_submit_urb(acm->writeurb, GFP_ATOMIC)) < 0) {
+        if ((rc = usb_submit_urb(wb->urb, GFP_ATOMIC)) < 0) {
                 dbg("usb_submit_urb(write bulk) failed: %d", rc);
-                acm_write_done(acm);
+                acm_write_done(acm, wb);
         }
         return rc;
 }
@@ -450,12 +442,13 @@ urbs:
 /* data interface wrote those outgoing bytes */
 static void acm_write_bulk(struct urb *urb)
 {
-        struct acm *acm = (struct acm *)urb->context;
+        struct acm *acm;
+        struct acm_wb *wb = (struct acm_wb *)urb->context;
 
         dbg("Entering acm_write_bulk with status %d", urb->status);
 
-        acm_write_done(acm);
-        acm_write_start(acm);
+        acm = wb->instance;
+        acm_write_done(acm, wb);
         if (ACM_READY(acm))
                 schedule_work(&acm->work);
 }
@@ -557,7 +550,8 @@ static void acm_tty_unregister(struct acm *acm)
         usb_put_intf(acm->control);
         acm_table[acm->minor] = NULL;
         usb_free_urb(acm->ctrlurb);
-        usb_free_urb(acm->writeurb);
+        for (i = 0; i < ACM_NW; i++)
+                usb_free_urb(acm->wb[i].urb);
         for (i = 0; i < nr; i++)
                 usb_free_urb(acm->ru[i].urb);
         kfree(acm->country_codes);
@@ -578,7 +572,8 @@ static void acm_tty_close(struct tty_struct *tty, struct file *filp)
                 if (acm->dev) {
                         acm_set_control(acm, acm->ctrlout = 0);
                         usb_kill_urb(acm->ctrlurb);
-                        usb_kill_urb(acm->writeurb);
+                        for (i = 0; i < ACM_NW; i++)
+                                usb_kill_urb(acm->wb[i].urb);
                         for (i = 0; i < nr; i++)
                                 usb_kill_urb(acm->ru[i].urb);
                         usb_autopm_put_interface(acm->control);
@@ -606,7 +601,6 @@ static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int c
         spin_lock_irqsave(&acm->write_lock, flags);
         if ((wbn = acm_wb_alloc(acm)) < 0) {
                 spin_unlock_irqrestore(&acm->write_lock, flags);
-                acm_write_start(acm);
                 return 0;
         }
         wb = &acm->wb[wbn];
@@ -617,7 +611,7 @@ static int acm_tty_write(struct tty_struct *tty, const unsigned char *buf, int c
         wb->len = count;
         spin_unlock_irqrestore(&acm->write_lock, flags);
 
-        if ((stat = acm_write_start(acm)) < 0)
+        if ((stat = acm_write_start(acm, wbn)) < 0)
                 return stat;
         return count;
 }
@@ -977,7 +971,7 @@ skip_normal_probe:
 
         ctrlsize = le16_to_cpu(epctrl->wMaxPacketSize);
         readsize = le16_to_cpu(epread->wMaxPacketSize)* ( quirks == SINGLE_RX_URB ? 1 : 2);
-        acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize);
+        acm->writesize = le16_to_cpu(epwrite->wMaxPacketSize) * 20;
         acm->control = control_interface;
         acm->data = data_interface;
         acm->minor = minor;
@@ -1032,10 +1026,19 @@ skip_normal_probe:
                         goto alloc_fail7;
                 }
         }
-        acm->writeurb = usb_alloc_urb(0, GFP_KERNEL);
-        if (!acm->writeurb) {
-                dev_dbg(&intf->dev, "out of memory (writeurb kmalloc)\n");
-                goto alloc_fail7;
+        for(i = 0; i < ACM_NW; i++)
+        {
+                struct acm_wb *snd = &(acm->wb[i]);
+
+                if (!(snd->urb = usb_alloc_urb(0, GFP_KERNEL))) {
+                        dev_dbg(&intf->dev, "out of memory (write urbs usb_alloc_urb)");
+                        goto alloc_fail7;
+                }
+
+                usb_fill_bulk_urb(snd->urb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
+                                NULL, acm->writesize, acm_write_bulk, snd);
+                snd->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
+                snd->instance = acm;
         }
 
         usb_set_intfdata (intf, acm);
@@ -1071,10 +1074,6 @@ skip_countries:
         acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
         acm->ctrlurb->transfer_dma = acm->ctrl_dma;
 
-        usb_fill_bulk_urb(acm->writeurb, usb_dev, usb_sndbulkpipe(usb_dev, epwrite->bEndpointAddress),
-                          NULL, acm->writesize, acm_write_bulk, acm);
-        acm->writeurb->transfer_flags |= URB_NO_FSBR | URB_NO_TRANSFER_DMA_MAP;
-
         dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
 
         acm_set_control(acm, acm->ctrlout);
@@ -1092,7 +1091,8 @@ skip_countries:
 
         return 0;
 alloc_fail8:
-        usb_free_urb(acm->writeurb);
+        for (i = 0; i < ACM_NW; i++)
+                usb_free_urb(acm->wb[i].urb);
 alloc_fail7:
         for (i = 0; i < num_rx_buf; i++)
                 usb_buffer_free(usb_dev, acm->readsize, acm->rb[i].base, acm->rb[i].dma);
@@ -1116,7 +1116,8 @@ static void stop_data_traffic(struct acm *acm)
         tasklet_disable(&acm->urb_task);
 
         usb_kill_urb(acm->ctrlurb);
-        usb_kill_urb(acm->writeurb);
+        for(i = 0; i < ACM_NW; i++)
+                usb_kill_urb(acm->wb[i].urb);
         for (i = 0; i < acm->rx_buflimit; i++)
                 usb_kill_urb(acm->ru[i].urb);
 
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index 8df6a57dcf9e..046e064b033a 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -59,7 +59,7 @@
  * when processing onlcr, so we only need 2 buffers. These values must be
  * powers of 2.
  */
-#define ACM_NW  2
+#define ACM_NW  16
 #define ACM_NR  16
 
 struct acm_wb {
@@ -67,6 +67,8 @@ struct acm_wb {
         dma_addr_t dmah;
         int len;
         int use;
+        struct urb              *urb;
+        struct acm              *instance;
 };
 
 struct acm_rb {
@@ -88,7 +90,7 @@ struct acm {
         struct usb_interface *control;                  /* control interface */
         struct usb_interface *data;                     /* data interface */
         struct tty_struct *tty;                         /* the corresponding tty */
-        struct urb *ctrlurb, *writeurb;                 /* urbs */
+        struct urb *ctrlurb;                    /* urbs */
         u8 *ctrl_buffer;                                /* buffers of urbs */
         dma_addr_t ctrl_dma;                            /* dma handles of buffers */
         u8 *country_codes;                              /* country codes from device */
@@ -103,7 +105,6 @@ struct acm {
         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;