USB: serial: add support for multiple read urbs
Add support for multiple read urbs to generic read implementation.
Use a static array of two read urbs for now which is enough to get a
50% throughput increase in one test setup.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index e4db5ad..f740357 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -1,7 +1,7 @@
/*
* USB Serial Converter Generic functions
*
- * Copyright (C) 2010 Johan Hovold (jhovold@gmail.com)
+ * Copyright (C) 2010 - 2011 Johan Hovold (jhovold@gmail.com)
* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
*
* This program is free software; you can redistribute it and/or
@@ -132,7 +132,7 @@
/* if we have a bulk endpoint, start reading from it */
if (port->bulk_in_size)
- result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
+ result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
return result;
}
@@ -157,8 +157,10 @@
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
}
- if (port->bulk_in_size)
- usb_kill_urb(port->read_urb);
+ if (port->bulk_in_size) {
+ for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
+ usb_kill_urb(port->read_urbs[i]);
+ }
}
}
@@ -308,19 +310,52 @@
return chars;
}
-int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
+static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
+ int index, gfp_t mem_flags)
+{
+ int res;
+
+ if (!test_and_clear_bit(index, &port->read_urbs_free))
+ return 0;
+
+ dbg("%s - port %d, urb %d\n", __func__, port->number, index);
+
+ res = usb_submit_urb(port->read_urbs[index], mem_flags);
+ if (res) {
+ if (res != -EPERM) {
+ dev_err(&port->dev,
+ "%s - usb_submit_urb failed: %d\n",
+ __func__, res);
+ }
+ set_bit(index, &port->read_urbs_free);
+ return res;
+ }
+
+ return 0;
+}
+
+int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
gfp_t mem_flags)
{
- int result;
+ int res;
+ int i;
- result = usb_submit_urb(port->read_urb, mem_flags);
- if (result && result != -EPERM) {
- dev_err(&port->dev, "%s - error submitting urb: %d\n",
- __func__, result);
+ dbg("%s - port %d", __func__, port->number);
+
+ for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
+ res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
+ if (res)
+ goto err;
}
- return result;
+
+ return 0;
+err:
+ for (; i >= 0; --i)
+ usb_kill_urb(port->read_urbs[i]);
+
+ return res;
}
-EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
+EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
void usb_serial_generic_process_read_urb(struct urb *urb)
{
@@ -356,14 +391,19 @@
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
- int status = urb->status;
unsigned long flags;
+ int i;
- dbg("%s - port %d", __func__, port->number);
+ for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
+ if (urb == port->read_urbs[i])
+ break;
+ }
+ set_bit(i, &port->read_urbs_free);
- if (unlikely(status != 0)) {
- dbg("%s - nonzero read bulk status received: %d",
- __func__, status);
+ dbg("%s - port %d, urb %d, len %d\n", __func__, port->number, i,
+ urb->actual_length);
+ if (urb->status) {
+ dbg("%s - non-zero urb status: %d\n", __func__, urb->status);
return;
}
@@ -376,7 +416,7 @@
port->throttled = port->throttle_req;
if (!port->throttled) {
spin_unlock_irqrestore(&port->lock, flags);
- usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
+ usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
} else
spin_unlock_irqrestore(&port->lock, flags);
}
@@ -443,7 +483,7 @@
spin_unlock_irq(&port->lock);
if (was_throttled)
- usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
+ usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
@@ -509,8 +549,9 @@
if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
continue;
- if (port->read_urb) {
- r = usb_submit_urb(port->read_urb, GFP_NOIO);
+ if (port->bulk_in_size) {
+ r = usb_serial_generic_submit_read_urbs(port,
+ GFP_NOIO);
if (r < 0)
c++;
}