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Diffstat (limited to 'drivers/usb/mon/mon_text.c')
-rw-r--r--drivers/usb/mon/mon_text.c23
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/usb/mon/mon_text.c b/drivers/usb/mon/mon_text.c
index 9f1a9227ebe6..047568ff223d 100644
--- a/drivers/usb/mon/mon_text.c
+++ b/drivers/usb/mon/mon_text.c
@@ -10,6 +10,7 @@
#include <linux/time.h>
#include <linux/mutex.h>
#include <linux/debugfs.h>
+#include <linux/scatterlist.h>
#include <asm/uaccess.h>
#include "usb_mon.h"
@@ -137,6 +138,8 @@ static inline char mon_text_get_setup(struct mon_event_text *ep,
static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
int len, char ev_type, struct mon_bus *mbus)
{
+ void *src;
+
if (len <= 0)
return 'L';
if (len >= DATA_MAX)
@@ -150,10 +153,24 @@ static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb,
return '>';
}
- if (urb->transfer_buffer == NULL)
- return 'Z'; /* '0' would be not as pretty. */
+ if (urb->num_sgs == 0) {
+ src = urb->transfer_buffer;
+ if (src == NULL)
+ return 'Z'; /* '0' would be not as pretty. */
+ } else {
+ struct scatterlist *sg = urb->sg->sg;
+
+ /* If IOMMU coalescing occurred, we cannot trust sg_page */
+ if (urb->sg->nents != urb->num_sgs ||
+ PageHighMem(sg_page(sg)))
+ return 'D';
+
+ /* For the text interface we copy only the first sg buffer */
+ len = min_t(int, sg->length, len);
+ src = sg_virt(sg);
+ }
- memcpy(ep->data, urb->transfer_buffer, len);
+ memcpy(ep->data, src, len);
return 0;
}