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[00/30] genirq: Treewide hunt for irq descriptor abuse and assorted fixes

Message ID 20201210192536.118432146@linutronix.de
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Series genirq: Treewide hunt for irq descriptor abuse and assorted fixes | expand

Message

Thomas Gleixner Dec. 10, 2020, 7:25 p.m. UTC 
A recent request to export kstat_irqs() pointed to a copy of the same in
the i915 code, which made me look for further usage of irq descriptors in
drivers.

The usage in drivers ranges from creative to broken in all colours.

irqdesc.h clearly says that this is core functionality and the fact C does
not allow full encapsulation is not a justification to fiddle with it just
because. It took us a lot of effort to make the core functionality provide
what drivers need.

If there is a shortcoming, it's not asked too much to talk to the relevant
maintainers instead of going off and fiddling with the guts of interrupt
descriptors and often enough without understanding lifetime and locking
rules.

As people insist on not respecting boundaries, this series cleans up the
(ab)use and at the end removes the export of irq_to_desc() to make it at
least harder. All legitimate users of this are built in.

While at it I stumbled over some other oddities related to interrupt
counting and cleaned them up as well.

The series applies on top of

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git irq/core

and is also available from git:

  git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git genirq

Thanks,

	tglx
---
 arch/alpha/kernel/sys_jensen.c                       |    2 
 arch/arm/kernel/smp.c                                |    2 
 arch/parisc/kernel/irq.c                             |    7 
 arch/s390/kernel/irq.c                               |    2 
 arch/x86/kernel/topology.c                           |    1 
 arch/arm64/kernel/smp.c                              |    2 
 drivers/gpu/drm/i915/display/intel_lpe_audio.c       |    4 
 drivers/gpu/drm/i915/i915_irq.c                      |   34 +++
 drivers/gpu/drm/i915/i915_pmu.c                      |   18 -
 drivers/gpu/drm/i915/i915_pmu.h                      |    8 
 drivers/mfd/ab8500-debugfs.c                         |   16 -
 drivers/net/ethernet/mellanox/mlx4/en_cq.c           |    8 
 drivers/net/ethernet/mellanox/mlx4/en_rx.c           |    6 
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h         |    3 
 drivers/net/ethernet/mellanox/mlx5/core/en.h         |    2 
 drivers/net/ethernet/mellanox/mlx5/core/en_main.c    |    2 
 drivers/net/ethernet/mellanox/mlx5/core/en_txrx.c    |    6 
 drivers/ntb/msi.c                                    |    4 
 drivers/pci/controller/mobiveil/pcie-mobiveil-host.c |    8 
 drivers/pci/controller/pcie-xilinx-nwl.c             |    8 
 drivers/pinctrl/nomadik/pinctrl-nomadik.c            |    3 
 drivers/xen/events/events_base.c                     |  172 +++++++++++--------
 drivers/xen/evtchn.c                                 |   34 ---
 include/linux/interrupt.h                            |    1 
 include/linux/irq.h                                  |    7 
 include/linux/irqdesc.h                              |   40 +---
 include/linux/kernel_stat.h                          |    1 
 kernel/irq/irqdesc.c                                 |   42 ++--
 kernel/irq/manage.c                                  |   37 ++++
 kernel/irq/proc.c                                    |    5 
 30 files changed, 263 insertions(+), 222 deletions(-)

Comments

Ville Syrjälä Dec. 10, 2020, 7:48 p.m. UTC | #1 
On Thu, Dec 10, 2020 at 08:25:49PM +0100, Thomas Gleixner wrote:
> Nothing uses the result and nothing should ever use it in driver code.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: David Airlie <airlied@linux.ie>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Pankaj Bharadiya <pankaj.laxminarayan.bharadiya@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Wambui Karuga <wambui.karugax@gmail.com>
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_lpe_audio.c |    4 ----
>  1 file changed, 4 deletions(-)
> 
> --- a/drivers/gpu/drm/i915/display/intel_lpe_audio.c
> +++ b/drivers/gpu/drm/i915/display/intel_lpe_audio.c
> @@ -297,13 +297,9 @@ int intel_lpe_audio_init(struct drm_i915
>   */
>  void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
>  {
> -	struct irq_desc *desc;
> -
>  	if (!HAS_LPE_AUDIO(dev_priv))
>  		return;
>  
> -	desc = irq_to_desc(dev_priv->lpe_audio.irq);
> -
>  	lpe_audio_platdev_destroy(dev_priv);
>  
>  	irq_free_desc(dev_priv->lpe_audio.irq);
> 
> _______________________________________________
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