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authorSarah Sharp <sarah.a.sharp@linux.intel.com>2009-05-14 11:44:14 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2009-06-15 21:44:51 -0700
commit6071d8363b7b284038069f1795a98372fbc1a48e (patch)
treee5b56ace01d240c49b1acbdc02f17cf6a2102fdc /drivers/usb/host
parent7dd19e69d131ea34f74397559b422511e54d2911 (diff)
usb; xhci: Fix TRB offset calculations.
Greg KH introduced a bug into xhci_trb_virt_to_dma() when he changed the type of offset to dma_addr_t from unsigned int and dropped the casts to unsigned int around the virtual address pointer subtraction. trb and seg->trbs are both valid pointers to virtual addresses, so the compiler will mod the subtraction by the size of union trb (16 bytes). segment_offset is an unsigned long, which is guaranteed to be at least as big as a void *. Drop the void * casts in the first if statement because trb and seg->trbs are both pointers of the same type (pointers to union trb). Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host')
-rw-r--r--drivers/usb/host/xhci-ring.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d42a738cdaa..02d81985c45 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -74,16 +74,15 @@
dma_addr_t xhci_trb_virt_to_dma(struct xhci_segment *seg,
union xhci_trb *trb)
{
- dma_addr_t offset;
+ unsigned long segment_offset;
- if (!seg || !trb || (void *) trb < (void *) seg->trbs)
+ if (!seg || !trb || trb < seg->trbs)
return 0;
- /* offset in bytes, since these are byte-addressable */
- offset = trb - seg->trbs;
- /* SEGMENT_SIZE in bytes, trbs are 16-byte aligned */
- if (offset > SEGMENT_SIZE || (offset % sizeof(*trb)) != 0)
+ /* offset in TRBs */
+ segment_offset = trb - seg->trbs;
+ if (segment_offset > TRBS_PER_SEGMENT)
return 0;
- return seg->dma + offset;
+ return seg->dma + (segment_offset * sizeof(*trb));
}
/* Does this link TRB point to the first segment in a ring,