From bcd2fde05341cef0052e49566ec88b406a521cf3 Mon Sep 17 00:00:00 2001
From: Paul Zimmerman <Paul.Zimmerman@synopsys.com>
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 <paulz@synopsys.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
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;
}