| From | Paul Gortmaker <> | Subject | [34-longterm 136/247] xhci: Fix an error in count_sg_trbs_needed() | Date | Thu, 23 Jun 2011 13:33:24 -0400 |
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From: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. -------------------
commit bcd2fde05341cef0052e49566ec88b406a521cf3 upstream.
The expression
while (running_total < sg_dma_len(sg))
does not take into account that the remaining data length can be less than sg_dma_len(sg). In that case, running_total can end up being greater than the total data length, so an extra TRB is counted. Changing the expression to
while (running_total < sg_dma_len(sg) && running_total < temp)
fixes that.
This patch should be queued for stable kernels back to 2.6.31.
Signed-off-by: Paul Zimmerman <paulz@synopsys.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- drivers/usb/host/xhci-ring.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index e4afa99..34ce5d4 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -1716,7 +1716,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb) num_trbs++; /* How many more 64KB chunks to transfer, how many more TRBs? */ - while (running_total < sg_dma_len(sg)) { + while (running_total < sg_dma_len(sg) && running_total < temp) { num_trbs++; running_total += TRB_MAX_BUFF_SIZE; } -- 1.7.4.4
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