irqdomain: Avoid activating interrupts more than once

Since commit f3b0946d629c ("genirq/msi: Make sure PCI MSIs are
activated early"), we can end-up activating a PCI/MSI twice (once
at allocation time, and once at startup time).

This is normally of no consequences, except that there is some
HW out there that may misbehave if activate is used more than once
(the GICv3 ITS, for example, uses the activate callback
to issue the MAPVI command, and the architecture spec says that
"If there is an existing mapping for the EventID-DeviceID
combination, behavior is UNPREDICTABLE").

While this could be worked around in each individual driver, it may
make more sense to tackle the issue at the core level. In order to
avoid getting in that situation, let's have a per-interrupt flag
to remember if we have already activated that interrupt or not.

Fixes: f3b0946d629c ("genirq/msi: Make sure PCI MSIs are activated early")
Reported-and-tested-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1484668848-24361-1-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

path: root/ipv6.h

#ifndef IPV6_H
#define IPV6_H

#include <asm/byteorder.h>

#include "built_in.h"

/*
 * IPv6 fixed header
 *
 * BEWARE, it is incorrect. The first 4 bits of flow_lbl
 * are glued to priority now, forming "class".
 */
struct ipv6hdr {
#if defined(__LITTLE_ENDIAN_BITFIELD)
	__extension__ uint8_t priority:4,
			      version:4;
#elif defined(__BIG_ENDIAN_BITFIELD)
	__extension__ uint8_t version:4,
			      priority:4;
#else
# error "Please fix <asm/byteorder.h>"
#endif
	uint8_t flow_lbl[3];
	uint16_t payload_len;
	uint8_t nexthdr;
	uint8_t hop_limit;
	struct in6_addr saddr;
	struct in6_addr daddr;
} __packed;

#endif /* IPV6_H */