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/include/rdma/mr_pool.h

/*
 * Copyright (c) 2016 HGST, a Western Digital Company.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 */
#ifndef _RDMA_MR_POOL_H
#define _RDMA_MR_POOL_H 1

#include <rdma/ib_verbs.h>

struct ib_mr *ib_mr_pool_get(struct ib_qp *qp, struct list_head *list);
void ib_mr_pool_put(struct ib_qp *qp, struct list_head *list, struct ib_mr *mr);

int ib_mr_pool_init(struct ib_qp *qp, struct list_head *list, int nr,
		enum ib_mr_type type, u32 max_num_sg);
void ib_mr_pool_destroy(struct ib_qp *qp, struct list_head *list);

#endif /* _RDMA_MR_POOL_H */