Calculations like running_total = TRB_MAX_BUFF_SIZE - (sg_dma_address(sg) & (TRB_MAX_BUFF_SIZE - 1)); if (running_total != 0) num_trbs++; are incorrect, because running_total can never be zero, so the if() expression will never be true. I think the intention was that running_total be in the range of 0 to TRB_MAX_BUFF_SIZE-1, not 1 to TRB_MAX_BUFF_SIZE. So adding a running_total &= TRB_MAX_BUFF_SIZE - 1; fixes the problem. Signed-off-by: Paul Zimmerman <paulz@xxxxxxxxxxxx> --- drivers/usb/host/xhci-ring.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index fe6dd81..8939086 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2375,6 +2375,7 @@ static unsigned int count_sg_trbs_needed(struct xhci_hcd *xhci, struct urb *urb) /* Scatter gather list entries may cross 64KB boundaries */ running_total = TRB_MAX_BUFF_SIZE - (sg_dma_address(sg) & (TRB_MAX_BUFF_SIZE - 1)); + running_total &= TRB_MAX_BUFF_SIZE - 1; if (running_total != 0) num_trbs++; @@ -2661,6 +2662,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, /* How much data is (potentially) left before the 64KB boundary? */ running_total = TRB_MAX_BUFF_SIZE - (urb->transfer_dma & (TRB_MAX_BUFF_SIZE - 1)); + running_total &= TRB_MAX_BUFF_SIZE - 1; /* If there's some data on this 64KB chunk, or we have to send a * zero-length transfer, we need at least one TRB @@ -2877,6 +2879,7 @@ static int count_isoc_trbs_needed(struct xhci_hcd *xhci, td_len = urb->iso_frame_desc[i].length; running_total = TRB_MAX_BUFF_SIZE - (addr & (TRB_MAX_BUFF_SIZE - 1)); + running_total &= TRB_MAX_BUFF_SIZE - 1; if (running_total != 0) num_trbs++; -- 1.6.5.1.69.g36942 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
