Commit 46539383 authored Jun 16, 2008 by Isaku Yamahata Committed by Ingo Molnar Jun 20, 2008

xen: Use wmb instead of rmb in xen_evtchn_do_upcall().

This patch is ported one from 534:77db69c38249 of linux-2.6.18-xen.hg.
Use wmb instead of rmb to enforce ordering between
evtchn_upcall_pending and evtchn_pending_sel stores
in xen_evtchn_do_upcall().

Cc: Samuel Thibault <samuel.thibault@eu.citrix.com>
Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: the arch/x86 maintainers <x86@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent 54481cf8

drivers/xen/events.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -529,7 +529,7 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)

		#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
		/* Clear master flag /before/ clearing selector flag. */
		rmb();
		wmb();
		#endif
		pending_words = xchg(&vcpu_info->evtchn_pending_sel, 0);
		while (pending_words != 0) {

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