Add an extra argument to the irq(domain) allocation functions, so we can hand
down affinity hints to the allocator. Thats necessary to implement proper
support for multiqueue devices.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-block@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-nvme@lists.infradead.org
Cc: axboe@fb.com
Cc: agordeev@redhat.com
Link: http://lkml.kernel.org/r/1467621574-8277-4-git-send-email-hch@lst.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Commit 7cec18a3 changed the return type of irq_destroy_ipi to int, but
missed adding a value to one return statement. Fix this to silence the
resulting compiler warning:

kernel/irq/ipi.c In function ‘irq_destroy_ipi’:
kernel/irq/ipi.c:128:3: warning: ‘return’ with no value, in function returning non-void [-Wreturn-type]

Fixes: 7cec18a3 "genirq: Add error code reporting to irq_{reserve,destroy}_ipi"
Signed-off-by: NMatt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/1464086550-24734-1-git-send-email-matt.redfearn@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Make these functions return appropriate error codes when something goes
wrong.

Previously irq_destroy_ipi returned void making it impossible to notify
the caller if the request could not be fulfilled. Patch 1 in the series
added another condition in which this could fail in addition to the
existing ones. irq_reserve_ipi returned an unsigned int meaning it could
only return 0 on failure and give the caller no indication as to why the
request failed.

As time goes on there are likely to be further conditions added in which
these functions can fail. These APIs and the IPI IRQ domain are new in
4.6 and the number of existing call sites are low, changing the API now
has little impact on the code, while making it easier for these
functions to grow over time.
Signed-off-by: NMatt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Cc: jiang.liu@linux.intel.com
Link: http://lkml.kernel.org/r/1461568464-31701-2-git-send-email-matt.redfearn@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Previously irq_destroy_ipi() would destroy IPIs to all CPUs that were
configured by irq_reserve_ipi(). This change makes it possible to
destroy just a subset of the IPIs. This may be useful to remove IPIs to
CPUs that have been hot removed so that the IRQ numbers allocated within
the IPI domain can be re-used.

The original behaviour is restored by passing the complete mask that the
IPI was created with.

There are currently no users of this function that would break from the
API change.
Signed-off-by: NMatt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Cc: jiang.liu@linux.intel.com
Link: http://lkml.kernel.org/r/1461568464-31701-1-git-send-email-matt.redfearn@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The IPI domain re-purposes the IRQ affinity to signify the mask of CPUs
that this IPI will deliver to. This must not be modified before the IPI
is destroyed again, so set the IRQ_NO_BALANCING flag to prevent the
affinity being overwritten by setup_affinity().

Without this, if an IPI is reserved for a single target CPU, then
allocated using __setup_irq(), the affinity is overwritten with
cpu_online_mask. When ipi_destroy() is subsequently called on a
multi-cpu system, it will attempt to free cpumask_weight() IRQs
that were never allocated, and crash.

Fixes: d17bf24e ("genirq: Add a new generic IPI reservation code to irq core")
Signed-off-by: NMatt Redfearn <matt.redfearn@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: jason@lakedaemon.net
Cc: marc.zyngier@arm.com
Cc: ralf@linux-mips.org
Cc: Qais Yousef <qsyousef@gmail.com>
Cc: lisa.parratt@imgtec.com
Link: http://lkml.kernel.org/r/1461229712-13057-1-git-send-email-matt.redfearn@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Add APIs to send IPIs from driver and arch code.

We have different functions because we allow architecture code to cache the
irq descriptor to avoid lookups. Driver code has to use the irq number and is
subject to more restrictive checks.

[ tglx: Polish the implementation ]
Signed-off-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: <jason@lakedaemon.net>
Cc: <marc.zyngier@arm.com>
Cc: <jiang.liu@linux.intel.com>
Cc: <ralf@linux-mips.org>
Cc: <linux-mips@linux-mips.org>
Cc: <lisa.parratt@imgtec.com>
Cc: Qais Yousef <qsyousef@gmail.com>
Link: http://lkml.kernel.org/r/1449580830-23652-12-git-send-email-qais.yousef@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When dealing with coprocessors we need to find out the actual hwirqs values to
pass on to the firmware so that it knows what it needs to use to receive IPIs
from and send IPIs to Linux cpus.

[ tglx: Fixed the single hwirq IPI case. The hardware irq number does not
  	change due to the cpu number ]
Signed-off-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: <jason@lakedaemon.net>
Cc: <marc.zyngier@arm.com>
Cc: <jiang.liu@linux.intel.com>
Cc: <ralf@linux-mips.org>
Cc: <linux-mips@linux-mips.org>
Cc: <lisa.parratt@imgtec.com>
Cc: Qais Yousef <qsyousef@gmail.com>
Link: http://lkml.kernel.org/r/1449580830-23652-10-git-send-email-qais.yousef@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Add a generic mechanism to dynamically allocate an IPI. Depending on the
underlying implementation this creates either a single Linux irq or a
consective range of Linux irqs. The Linux irq is used later to send IPIs to
other CPUs.

[ tglx: Massaged the code and removed the 'consecutive mask' restriction for
  	the single IRQ case ]
Signed-off-by: NQais Yousef <qais.yousef@imgtec.com>
Cc: <jason@lakedaemon.net>
Cc: <marc.zyngier@arm.com>
Cc: <jiang.liu@linux.intel.com>
Cc: <ralf@linux-mips.org>
Cc: <linux-mips@linux-mips.org>
Cc: <lisa.parratt@imgtec.com>
Cc: Qais Yousef <qsyousef@gmail.com>
Link: http://lkml.kernel.org/r/1449580830-23652-9-git-send-email-qais.yousef@imgtec.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>