From bcd2fde05341cef0052e49566ec88b406a521cf3 Mon Sep 17 00:00:00 2001 From: Paul Zimmerman Date: Sat, 12 Feb 2011 14:07:57 -0800 Subject: [PATCH] xhci: Fix an error in count_sg_trbs_needed() 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 Signed-off-by: Sarah Sharp Cc: stable@kernel.org --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index dbbeec96ce1d..3289bf4832c9 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2374,7 +2374,7 @@ 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; }