linux-toradex.git/kernel/irq/irqdesc.c, branch v4.9.120

genirq: Make sparse_irq_lock protect what it should protect

2017-10-05T07:43:58+00:00

commit 12ac1d0f6c3e95732d144ffa65c8b20fbd9aa462 upstream.

for_each_active_irq() iterates the sparse irq allocation bitmap. The caller
must hold sparse_irq_lock. Several code pathes expect that an active bit in
the sparse bitmap also has a valid interrupt descriptor.

Unfortunately that's not true. The (de)allocation is a two step process,
which holds the sparse_irq_lock only across the queue/remove from the radix
tree and the set/clear in the allocation bitmap.

If a iteration locks sparse_irq_lock between the two steps, then it might
see an active bit but the corresponding irq descriptor is NULL. If that is
dereferenced unconditionally, then the kernel oopses. Of course, all
iterator sites could be audited and fixed, but....

There is no reason why the sparse_irq_lock needs to be dropped between the
two steps, in fact the code becomes simpler when the mutex is held across
both and the semantics become more straight forward, so future problems of
missing NULL pointer checks in the iteration are avoided and all existing
sites are fixed in one go.

Expand the lock held sections so both operations are covered and the bitmap
and the radixtree are in sync.

Fixes: a05a900a51c7 ("genirq: Make sparse_lock a mutex")
Reported-and-tested-by: Huang Ying 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'irq/for-block' into irq/core

2016-09-15T18:54:40+00:00

Add the new irq spreading infrastructure.

genirq/msi: Switch to new irq spreading infrastructure

2016-09-14T20:11:09+00:00

Switch MSI over to the new spreading code. If a pci device contains a valid
pointer to a cpumask, then this mask is used for spreading otherwise the
online cpu mask is used. This allows a driver to restrict the spread to a
subset of CPUs, e.g. cpus on a particular node.

Signed-off-by: Thomas Gleixner 
Cc: Christoph Hellwig 
Cc: axboe@fb.com
Cc: keith.busch@intel.com
Cc: agordeev@redhat.com
Cc: linux-block@vger.kernel.org
Link: http://lkml.kernel.org/r/1473862739-15032-4-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner

genirq: Expose interrupt information through sysfs

2016-09-14T13:28:15+00:00

Information about interrupts is exposed via /proc/interrupts, but the
format of that file has changed over kernel versions and differs across
architectures. It also has varying column numbers depending on hardware.

That all makes it hard for tools to parse.

To solve this, expose the information through sysfs so each irq attribute
is in a separate file in a consistent, machine parsable way.

This feature is only available when both CONFIG_SPARSE_IRQ and
CONFIG_SYSFS are enabled.

Examples:
  /sys/kernel/irq/18/actions:	i801_smbus,ehci_hcd:usb1,uhci_hcd:usb7
  /sys/kernel/irq/18/chip_name:	IR-IO-APIC
  /sys/kernel/irq/18/hwirq:		18
  /sys/kernel/irq/18/name:		fasteoi
  /sys/kernel/irq/18/per_cpu_count:	0,0
  /sys/kernel/irq/18/type:		level

  /sys/kernel/irq/25/actions:	ahci0
  /sys/kernel/irq/25/chip_name:	IR-PCI-MSI
  /sys/kernel/irq/25/hwirq:		512000
  /sys/kernel/irq/25/name:		edge
  /sys/kernel/irq/25/per_cpu_count:	29036,0
  /sys/kernel/irq/25/type:		edge

[ tglx: Moved kobject_del() under sparse_irq_lock, massaged code comments
  	and changelog ]

Signed-off-by: Craig Gallek 
Cc: David Decotigny 
Link: http://lkml.kernel.org/r/1473783291-122873-1-git-send-email-kraigatgoog@gmail.com
Signed-off-by: Thomas Gleixner

genirq: Use affinity hint in irqdesc allocation

2016-07-04T10:25:13+00:00

Use the affinity hint in the irqdesc allocator. The hint is used to determine
the node for the allocation and to set the affinity of the interrupt.

If multiple interrupts are allocated (multi-MSI) then the allocator iterates
over the cpumask and for each set cpu it allocates on their node and sets the
initial affinity to that cpu.

If a single interrupt is allocated (MSI-X) then the allocator uses the first
cpu in the mask to compute the allocation node and uses the mask for the
initial affinity setting.

Interrupts set up this way are marked with the AFFINITY_MANAGED flag to
prevent userspace from messing with their affinity settings.

Signed-off-by: Thomas Gleixner 
Cc: Christoph Hellwig 
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/1467621574-8277-5-git-send-email-hch@lst.de
Signed-off-by: Thomas Gleixner

genirq: Add affinity hint to irq allocation

2016-07-04T10:25:13+00:00

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: Thomas Gleixner 
Cc: Christoph Hellwig 
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.de
Signed-off-by: Thomas Gleixner

genirq: Allow the affinity of a percpu interrupt to be set/retrieved

2016-05-02T11:42:51+00:00

In order to prepare the genirq layer for the concept of partitionned
percpu interrupts, let's allow an affinity to be associated with
such an interrupt. We introduce:

- irq_set_percpu_devid_partition: flag an interrupt as a percpu-devid
  interrupt, and associate it with an affinity
- irq_get_percpu_devid_partition: allow the affinity of that interrupt
  to be retrieved.

This will allow a driver to discover which CPUs the per-cpu interrupt
can actually fire on.

Signed-off-by: Marc Zyngier 
Cc: Mark Rutland 
Cc: devicetree@vger.kernel.org
Cc: Jason Cooper 
Cc: Will Deacon 
Cc: Rob Herring 
Link: http://lkml.kernel.org/r/1460365075-7316-3-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner

genirq: Add default affinity mask command line option

2016-02-08T14:03:42+00:00

If we isolate CPUs, then we don't want random device interrupts on them. Even
w/o the user space irq balancer enabled we can end up with irqs on non boot
cpus and chasing newly requested interrupts is a tedious task.

Allow to restrict the default irq affinity mask.

Signed-off-by: Thomas Gleixner 
Cc: Rik van Riel 
Cc: Peter Zijlstra 
Cc: Frederic Weisbecker 
Cc: Chris Metcalf 
Cc: Christoph Lameter 
Cc: Sebastian Siewior 
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1602031948190.25254@nanos
Signed-off-by: Thomas Gleixner

genirq: Free irq_desc with rcu

2015-12-14T09:03:46+00:00

The new VMD device driver needs to iterate over a list of
"demultiplexing" interrupts. Protecting that list with a lock is not
possible because the list is also required in code pathes which hold
irq descriptor lock. Therefor the demultiplexing interrupt handler
would create a lock inversion scenario if it calls a demux handler
with the list protection lock held.

A solution for this is to free the irq descriptor via RCU, so the
list can be walked with rcu read lock held.

Signed-off-by: Thomas Gleixner 
Cc: Keith Busch

genirq: Remove irq argument from irq flow handlers

2015-09-16T13:47:51+00:00

Most interrupt flow handlers do not use the irq argument. Those few
which use it can retrieve the irq number from the irq descriptor.

Remove the argument.

Search and replace was done with coccinelle and some extra helper
scripts around it. Thanks to Julia for her help!

Signed-off-by: Thomas Gleixner 
Cc: Julia Lawall 
Cc: Jiang Liu