| From | Andi Kleen <> | Subject | [PATCH] [157/275] xhci: Fix an error in count_sg_trbs_needed() | Date | Wed, 30 Mar 2011 14:06:38 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
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: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux-2.6.35.y/drivers/usb/host/xhci-ring.c =================================================================== --- linux-2.6.35.y.orig/drivers/usb/host/xhci-ring.c 2011-03-29 23:03:01.504261681 -0700 +++ linux-2.6.35.y/drivers/usb/host/xhci-ring.c 2011-03-29 23:54:12.392685328 -0700 @@ -1896,7 +1896,7 @@ 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; }
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