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| author | Sarah Sharp <sarah.a.sharp@linux.intel.com> | 2009-05-14 20:44:14 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-06-16 06:44:51 +0200 |
| commit | 6071d8363b7b284038069f1795a98372fbc1a48e (patch) | |
| tree | e5b56ace01d240c49b1acbdc02f17cf6a2102fdc /drivers/usb | |
| parent | USB: xhci: replace if-elseif-else with switch-case (diff) | |
| download | linux-6071d8363b7b284038069f1795a98372fbc1a48e.tar.xz linux-6071d8363b7b284038069f1795a98372fbc1a48e.zip | |
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')
| -rw-r--r-- | drivers/usb/host/xhci-ring.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index d42a738cdaa7..02d81985c454 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, |