USB: don't use a fixed DMA mapping for hub status URBs

This patch (as1296) gets rid of the fixed DMA-buffer mapping used by
the hub driver for its status URB.  This URB doesn't get used much --
mainly when a device is plugged in or unplugged -- so the dynamic
mapping overhead is minimal.  And most systems have many fewer
external hubs than root hubs, which don't need a mapped buffer anyway.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 2 insertions, 7 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 2ac115015229..708c63826100 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -45,7 +45,6 @@ struct usb_hub {
 
         /* buffer for urb ... with extra space in case of babble */
         char                    (*buffer)[8];
-        dma_addr_t              buffer_dma;     /* DMA address for buffer */
         union {
                 struct usb_hub_status   hub;
                 struct usb_port_status  port;
@@ -869,8 +868,7 @@ static int hub_configure(struct usb_hub *hub,
         int maxp, ret;
         char *message = "out of memory";
 
-        hub->buffer = usb_buffer_alloc(hdev, sizeof(*hub->buffer), GFP_KERNEL,
-                        &hub->buffer_dma);
+        hub->buffer = kmalloc(sizeof(*hub->buffer), GFP_KERNEL);
         if (!hub->buffer) {
                 ret = -ENOMEM;
                 goto fail;
@@ -1111,8 +1109,6 @@ static int hub_configure(struct usb_hub *hub,
 
         usb_fill_int_urb(hub->urb, hdev, pipe, *hub->buffer, maxp, hub_irq,
                 hub, endpoint->bInterval);
-        hub->urb->transfer_dma = hub->buffer_dma;
-        hub->urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
 
         /* maybe cycle the hub leds */
         if (hub->has_indicators && blinkenlights)
@@ -1162,8 +1158,7 @@ static void hub_disconnect(struct usb_interface *intf)
         kfree(hub->port_owners);
         kfree(hub->descriptor);
         kfree(hub->status);
-        usb_buffer_free(hub->hdev, sizeof(*hub->buffer), hub->buffer,
-                        hub->buffer_dma);
+        kfree(hub->buffer);
 
         kref_put(&hub->kref, hub_release);
 }