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authorPete Zaitcev <zaitcev@redhat.com>2009-06-11 08:53:20 -0600
committerGreg Kroah-Hartman <gregkh@suse.de>2009-09-23 06:46:19 -0700
commit4e9e92003529e5c7bb11281f7c2c9b3fe8858403 (patch)
tree07169c9a996a119aebb5865a76ff1177afe90a22 /drivers/usb/mon/usb_mon.h
parentf4e2332cfcf900e0a926c4e0fc35f751bcbcaa1b (diff)
USB: usbmon: end ugly tricks with DMA peeking
This patch fixes crashes when usbmon attempts to access GART aperture. The old code attempted to take a bus address and convert it into a virtual address, which clearly was impossible on systems with actual IOMMUs. Let us not persist in this foolishness, and use transfer_buffer in all cases instead. I think downsides are negligible. The ones I see are: - A driver may pass an address of one buffer down as transfer_buffer, and entirely different entity mapped for DMA, resulting in misleading output of usbmon. Note, however, that PIO based controllers would do transfer the same data that usbmon sees here. - Out of tree drivers may crash usbmon if they store garbage in transfer_buffer. I inspected the in-tree drivers, and clarified the documentation in comments. - Drivers that use get_user_pages will not be possible to monitor. I only found one driver with this problem (drivers/staging/rspiusb). - Same happens with with usb_storage transferring from highmem, but it works fine on 64-bit systems, so I think it's not a concern. At least we don't crash anymore. Why didn't we do this in 2.6.10? That's because back in those days it was popular not to fill in transfer_buffer, so almost all traffic would be invisible (e.g. all of HID was like that). But now, the tree is almost 100% PIO friendly, so we can do the right thing at last. Signed-off-by: Pete Zaitcev <zaitcev@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/mon/usb_mon.h')
-rw-r--r--drivers/usb/mon/usb_mon.h14
1 files changed, 0 insertions, 14 deletions
diff --git a/drivers/usb/mon/usb_mon.h b/drivers/usb/mon/usb_mon.h
index f5d84ff8c10..df9a4df342c 100644
--- a/drivers/usb/mon/usb_mon.h
+++ b/drivers/usb/mon/usb_mon.h
@@ -65,20 +65,6 @@ int __init mon_bin_init(void);
void mon_bin_exit(void);
/*
- * DMA interface.
- *
- * XXX The vectored side needs a serious re-thinking. Abstracting vectors,
- * like in Paolo's original patch, produces a double pkmap. We need an idea.
-*/
-extern char mon_dmapeek(unsigned char *dst, dma_addr_t dma_addr, int len);
-
-struct mon_reader_bin;
-extern void mon_dmapeek_vec(const struct mon_reader_bin *rp,
- unsigned int offset, dma_addr_t dma_addr, unsigned int len);
-extern unsigned int mon_copy_to_buff(const struct mon_reader_bin *rp,
- unsigned int offset, const unsigned char *from, unsigned int len);
-
-/*
*/
extern struct mutex mon_lock;