From: Matt Evans Date: Tue, 29 Mar 2011 02:40:51 +0000 (+1100) Subject: xhci: Add rmb() between reading event validity & event data access. X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=92a3da410aac6e14daaefe13c60368ca28e85830;p=linux-beck.git xhci: Add rmb() between reading event validity & event data access. On weakly-ordered systems, the reading of an event's content must occur after reading the event's validity. Signed-off-by: Matt Evans Signed-off-by: Sarah Sharp --- diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 9b1eeb04ce69..e0f05f5abe10 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -2193,6 +2193,11 @@ static void xhci_handle_event(struct xhci_hcd *xhci) } xhci_dbg(xhci, "%s - OS owns TRB\n", __func__); + /* + * Barrier between reading the TRB_CYCLE (valid) flag above and any + * speculative reads of the event's flags/data below. + */ + rmb(); /* FIXME: Handle more event types. */ switch ((le32_to_cpu(event->event_cmd.flags) & TRB_TYPE_BITMASK)) { case TRB_TYPE(TRB_COMPLETION):