USB: serial: re-implement multi-urb writes in generic driver
Use dynamic transfer buffer sizes since it is more efficient to let the host controller do the partitioning to fit endpoint size. This way we also do not use more than one urb per write request. Replace max_in_flight_urbs with multi_urb_write flag in struct usb_serial_driver to enable multi-urb writes. Use MAX_TX_URBS=40 and a max buffer size of PAGE_SIZE to prevent DoS attacks. Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Johan Hovold
Greg Kroah-Hartman
Родитель
40f92f0dcd
Коммит
25d514ca22
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@ -25,6 +25,8 @@
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static int debug;
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#define MAX_TX_URBS 40
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#ifdef CONFIG_USB_SERIAL_GENERIC
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static int generic_probe(struct usb_interface *interface,
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@ -172,78 +174,63 @@ static int usb_serial_multi_urb_write(struct tty_struct *tty,
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struct urb *urb;
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unsigned char *buffer;
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int status;
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int towrite;
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int bwrite = 0;
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dbg("%s - port %d", __func__, port->number);
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if (count == 0)
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dbg("%s - write request of 0 bytes", __func__);
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while (count > 0) {
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towrite = (count > port->bulk_out_size) ?
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port->bulk_out_size : count;
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spin_lock_irqsave(&port->lock, flags);
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if (port->urbs_in_flight >
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port->serial->type->max_in_flight_urbs) {
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if (port->tx_urbs == MAX_TX_URBS) {
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - write limit hit", __func__);
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return bwrite;
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return 0;
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}
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port->tx_bytes_flight += towrite;
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port->urbs_in_flight++;
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port->tx_urbs++;
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spin_unlock_irqrestore(&port->lock, flags);
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buffer = kmalloc(towrite, GFP_ATOMIC);
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if (!buffer) {
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dev_err(&port->dev,
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"%s ran out of kernel memory for urb ...\n", __func__);
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goto error_no_buffer;
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}
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urb = usb_alloc_urb(0, GFP_ATOMIC);
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if (!urb) {
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dev_err(&port->dev, "%s - no more free urbs\n",
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__func__);
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goto error_no_urb;
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dev_err(&port->dev, "%s - no free urbs available\n", __func__);
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status = -ENOMEM;
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goto err_urb;
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}
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/* Copy data */
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memcpy(buffer, buf + bwrite, towrite);
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usb_serial_debug_data(debug, &port->dev, __func__,
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towrite, buffer);
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/* fill the buffer and send it */
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count = min_t(int, count, PAGE_SIZE);
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buffer = kmalloc(count, GFP_ATOMIC);
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if (!buffer) {
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dev_err(&port->dev, "%s - could not allocate buffer\n",
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__func__);
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status = -ENOMEM;
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goto err_buf;
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}
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memcpy(buffer, buf, count);
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usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
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usb_fill_bulk_urb(urb, port->serial->dev,
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usb_sndbulkpipe(port->serial->dev,
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port->bulk_out_endpointAddress),
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buffer, towrite,
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buffer, count,
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port->serial->type->write_bulk_callback, port);
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status = usb_submit_urb(urb, GFP_ATOMIC);
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if (status) {
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dev_err(&port->dev, "%s - error submitting urb: %d\n",
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__func__, status);
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goto error;
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goto err;
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}
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/* This urb is the responsibility of the host driver now */
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usb_free_urb(urb);
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dbg("%s write: %d", __func__, towrite);
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count -= towrite;
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bwrite += towrite;
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}
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return bwrite;
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error:
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usb_free_urb(urb);
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error_no_urb:
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kfree(buffer);
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error_no_buffer:
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spin_lock_irqsave(&port->lock, flags);
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port->urbs_in_flight--;
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port->tx_bytes_flight -= towrite;
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port->tx_bytes += urb->transfer_buffer_length;
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spin_unlock_irqrestore(&port->lock, flags);
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return bwrite;
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usb_free_urb(urb);
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return count;
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err:
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kfree(buffer);
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err_buf:
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usb_free_urb(urb);
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err_urb:
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spin_lock_irqsave(&port->lock, flags);
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port->tx_urbs--;
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spin_unlock_irqrestore(&port->lock, flags);
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return status;
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}
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/**
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@ -286,7 +273,7 @@ static int usb_serial_generic_write_start(struct usb_serial_port *port)
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}
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spin_lock_irqsave(&port->lock, flags);
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port->tx_bytes_flight += count;
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port->tx_bytes += count;
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spin_unlock_irqrestore(&port->lock, flags);
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return count;
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@ -318,9 +305,8 @@ int usb_serial_generic_write(struct tty_struct *tty,
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if (!count)
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return 0;
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if (serial->type->max_in_flight_urbs)
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return usb_serial_multi_urb_write(tty, port,
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buf, count);
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if (serial->type->multi_urb_write)
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return usb_serial_multi_urb_write(tty, port, buf, count);
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count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
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result = usb_serial_generic_write_start(port);
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@ -337,7 +323,7 @@ int usb_serial_generic_write_room(struct tty_struct *tty)
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struct usb_serial_port *port = tty->driver_data;
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struct usb_serial *serial = port->serial;
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unsigned long flags;
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int room = 0;
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int room;
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dbg("%s - port %d", __func__, port->number);
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@ -345,14 +331,10 @@ int usb_serial_generic_write_room(struct tty_struct *tty)
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return 0;
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spin_lock_irqsave(&port->lock, flags);
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if (serial->type->max_in_flight_urbs) {
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if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
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room = port->bulk_out_size *
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(serial->type->max_in_flight_urbs -
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port->urbs_in_flight);
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} else {
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if (serial->type->multi_urb_write)
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room = (MAX_TX_URBS - port->tx_urbs) * PAGE_SIZE;
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else
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room = kfifo_avail(&port->write_fifo);
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}
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - returns %d", __func__, room);
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@ -372,10 +354,10 @@ int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
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return 0;
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spin_lock_irqsave(&port->lock, flags);
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if (serial->type->max_in_flight_urbs)
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chars = port->tx_bytes_flight;
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if (serial->type->multi_urb_write)
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chars = port->tx_bytes;
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else
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chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
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chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
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spin_unlock_irqrestore(&port->lock, flags);
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dbg("%s - returns %d", __func__, chars);
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@ -461,18 +443,16 @@ void usb_serial_generic_write_bulk_callback(struct urb *urb)
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dbg("%s - port %d", __func__, port->number);
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if (port->serial->type->max_in_flight_urbs) {
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if (port->serial->type->multi_urb_write) {
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kfree(urb->transfer_buffer);
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spin_lock_irqsave(&port->lock, flags);
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--port->urbs_in_flight;
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port->tx_bytes_flight -= urb->transfer_buffer_length;
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if (port->urbs_in_flight < 0)
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port->urbs_in_flight = 0;
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port->tx_bytes -= urb->transfer_buffer_length;
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port->tx_urbs--;
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spin_unlock_irqrestore(&port->lock, flags);
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} else {
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spin_lock_irqsave(&port->lock, flags);
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port->tx_bytes_flight -= urb->transfer_buffer_length;
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port->tx_bytes -= urb->transfer_buffer_length;
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port->write_urb_busy = 0;
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spin_unlock_irqrestore(&port->lock, flags);
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@ -60,6 +60,8 @@ enum port_dev_state {
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* @write_urb: pointer to the bulk out struct urb for this port.
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* @write_fifo: kfifo used to buffer outgoing data
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* @write_urb_busy: port`s writing status
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* @tx_bytes: number of bytes currently in host stack queues
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* @tx_urbs: number of urbs currently in host stack queues
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* @bulk_out_endpointAddress: endpoint address for the bulk out pipe for this
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* port.
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* @write_wait: a wait_queue_head_t used by the port.
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@ -98,8 +100,8 @@ struct usb_serial_port {
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int write_urb_busy;
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__u8 bulk_out_endpointAddress;
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int tx_bytes_flight;
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int urbs_in_flight;
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int tx_bytes;
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int tx_urbs;
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wait_queue_head_t write_wait;
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struct work_struct work;
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@ -223,7 +225,8 @@ struct usb_serial_driver {
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struct device_driver driver;
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struct usb_driver *usb_driver;
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struct usb_dynids dynids;
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int max_in_flight_urbs;
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unsigned char multi_urb_write:1;
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size_t bulk_in_size;
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size_t bulk_out_size;
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