usbmon: don't call mon_dmapeek if DMA isn't being used

This patch (as755b) fixes a bug in usbmon.  Rather than assuming all
USB host controllers use DMA, the code will check the usb_bus data
structure.  If DMA isn't used, we don't want to try peeking into a
non-existent DMA buffer!

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

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/usb/mon/mon_main.c b/drivers/usb/mon/mon_main.c
index e0ed36cdfd8b..394bbf2f68d4 100644
--- a/drivers/usb/mon/mon_main.c
+++ b/drivers/usb/mon/mon_main.c
@@ -301,6 +301,7 @@ static void mon_bus_init(struct dentry *mondir, struct usb_bus *ubus)
          */
         mbus->u_bus = ubus;
         ubus->mon_bus = mbus;
+        mbus->uses_dma = ubus->uses_dma;
 
         rc = snprintf(name, NAMESZ, "%dt", ubus->busnum);
         if (rc <= 0 || rc >= NAMESZ)