[PATCH] usbmon in 2.6.13: peeking into DMA areas

This code looks at urb->transfer_dma, maps the page and takes the data.
I am looking for volunteers to contribute architectures other than i386
or to develop an architecure-neutral API for it (or point me that it
was done already).

Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 18 deletions

diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index 26266b30028e..417464dea9f6 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -91,25 +91,11 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
     int len, char ev_type)
 {
         int pipe = urb->pipe;
-        unsigned char *data;
-
-        /*
-         * The check to see if it's safe to poke at data has an enormous
-         * number of corner cases, but it seems that the following is
-         * more or less safe.
-         *
-         * We do not even try to look transfer_buffer, because it can
-         * contain non-NULL garbage in case the upper level promised to
-         * set DMA for the HCD.
-         */
-        if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
-                return 'D';
 
         if (len <= 0)
                 return 'L';
-
-        if ((data = urb->transfer_buffer) == NULL)
-                return 'Z';     /* '0' would be not as pretty. */
+        if (len >= DATA_MAX)
+                len = DATA_MAX;
 
         /*
          * Bulk is easy to shortcut reliably. 
@@ -126,8 +112,21 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
                 }
         }
 
-        if (len >= DATA_MAX)
-                len = DATA_MAX;
+        /*
+         * The check to see if it's safe to poke at data has an enormous
+         * number of corner cases, but it seems that the following is
+         * more or less safe.
+         *
+         * We do not even try to look transfer_buffer, because it can
+         * contain non-NULL garbage in case the upper level promised to
+         * set DMA for the HCD.
+         */
+        if (urb->transfer_flags & URB_NO_TRANSFER_DMA_MAP)
+                return mon_dmapeek(ep->data, urb->transfer_dma, len);
+
+        if (urb->transfer_buffer == NULL)
+                return 'Z';     /* '0' would be not as pretty. */
+
         memcpy(ep->data, urb->transfer_buffer, len);
         return 0;
 }