[PATCH 0/2] genirq: Kill preflow handlers

[PATCH 0/2] genirq: Kill preflow handlers

[Valentin Schneider]

Hi,

while strolling around the different flow handlers, I tried to make sense of
what preflow_handler() was about. Turns out no one uses those anymore, but the
genirq support has remained in place.

Unless we can see another user of those in the near future, this seems like as
good a time as any for a little housecleaning.

- Patch 1 simply deselects the (unexploited) preflow Kconfig for sparc64
- Patch 2 is the actual cleanup

Cheers,
Valentin

Valentin Schneider (2):
  sparc64: Deselect IRQ_PREFLOW_FASTEOI
  genirq: Remove preflow handler support

 arch/sparc/Kconfig         |  1 -
 include/linux/irqdesc.h    | 15 ---------------
 include/linux/irqhandler.h |  1 -
 kernel/irq/Kconfig         |  4 ----
 kernel/irq/chip.c          | 13 -------------
 5 files changed, 34 deletions(-)

--
2.27.0

[PATCH 1/2] sparc64: Deselect IRQ_PREFLOW_FASTEOI

[Valentin Schneider]

sparc64 hasn't needed to select this since commit:

  ee6a9333fa58 ("sparc64: sparse irq")

which got rid of the calls to __irq_set_preflow_handler() first installed
by commit:

  fcd8d4f49869 ("sparc: Use the new genirq functionality")

Deselect this option.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
 arch/sparc/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index da515fdad83d..ed35760043e8 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -81,7 +81,6 @@ config SPARC64
 	select RTC_DRV_STARFIRE
 	select HAVE_PERF_EVENTS
 	select PERF_USE_VMALLOC
-	select IRQ_PREFLOW_FASTEOI
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_C_RECORDMCOUNT
 	select HAVE_ARCH_AUDITSYSCALL
-- 
2.27.0

[PATCH 2/2] genirq: Remove preflow handler support

[Valentin Schneider]

That was put in place for sparc64, and blackfin also used it for some time;
sparc64 no longer uses those, and blackfin is dead.

As there are no more users, remove preflow handlers.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
---
 include/linux/irqdesc.h    | 15 ---------------
 include/linux/irqhandler.h |  1 -
 kernel/irq/Kconfig         |  4 ----
 kernel/irq/chip.c          | 13 -------------
 4 files changed, 33 deletions(-)

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 8f2820c5e69e..5745491303e0 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -22,7 +22,6 @@ struct pt_regs;
  * @irq_common_data:	per irq and chip data passed down to chip functions
  * @kstat_irqs:		irq stats per cpu
  * @handle_irq:		highlevel irq-events handler
- * @preflow_handler:	handler called before the flow handler (currently used by sparc)
  * @action:		the irq action chain
  * @status_use_accessors: status information
  * @core_internal_state__do_not_mess_with_it: core internal status information
@@ -58,9 +57,6 @@ struct irq_desc {
 	struct irq_data		irq_data;
 	unsigned int __percpu	*kstat_irqs;
 	irq_flow_handler_t	handle_irq;
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-	irq_preflow_handler_t	preflow_handler;
-#endif
 	struct irqaction	*action;	/* IRQ action list */
 	unsigned int		status_use_accessors;
 	unsigned int		core_internal_state__do_not_mess_with_it;
@@ -268,15 +264,4 @@ irq_set_lockdep_class(unsigned int irq, struct lock_class_key *lock_class,
 	}
 }
 
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-static inline void
-__irq_set_preflow_handler(unsigned int irq, irq_preflow_handler_t handler)
-{
-	struct irq_desc *desc;
-
-	desc = irq_to_desc(irq);
-	desc->preflow_handler = handler;
-}
-#endif
-
 #endif
diff --git a/include/linux/irqhandler.h b/include/linux/irqhandler.h
index 1e6f4e7123d6..c30f454a9518 100644
--- a/include/linux/irqhandler.h
+++ b/include/linux/irqhandler.h
@@ -10,6 +10,5 @@
 struct irq_desc;
 struct irq_data;
 typedef	void (*irq_flow_handler_t)(struct irq_desc *desc);
-typedef	void (*irq_preflow_handler_t)(struct irq_data *data);
 
 #endif
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index d63c324895ea..58f0e996a2c3 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -51,10 +51,6 @@ config GENERIC_IRQ_INJECTION
 config HARDIRQS_SW_RESEND
        bool
 
-# Preflow handler support for fasteoi (sparc64)
-config IRQ_PREFLOW_FASTEOI
-       bool
-
 # Edge style eoi based handler (cell)
 config IRQ_EDGE_EOI_HANDLER
        bool
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 41e7e37a0928..75bbaa8b38f1 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -656,16 +656,6 @@ void handle_level_irq(struct irq_desc *desc)
 }
 EXPORT_SYMBOL_GPL(handle_level_irq);
 
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-static inline void preflow_handler(struct irq_desc *desc)
-{
-	if (desc->preflow_handler)
-		desc->preflow_handler(&desc->irq_data);
-}
-#else
-static inline void preflow_handler(struct irq_desc *desc) { }
-#endif
-
 static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
 {
 	if (!(desc->istate & IRQS_ONESHOT)) {
@@ -721,7 +711,6 @@ void handle_fasteoi_irq(struct irq_desc *desc)
 	if (desc->istate & IRQS_ONESHOT)
 		mask_irq(desc);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);
@@ -1231,7 +1220,6 @@ void handle_fasteoi_ack_irq(struct irq_desc *desc)
 	/* Start handling the irq */
 	desc->irq_data.chip->irq_ack(&desc->irq_data);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);
@@ -1281,7 +1269,6 @@ void handle_fasteoi_mask_irq(struct irq_desc *desc)
 	if (desc->istate & IRQS_ONESHOT)
 		mask_irq(desc);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);
-- 
2.27.0

Re: [PATCH 1/2] sparc64: Deselect IRQ_PREFLOW_FASTEOI

[Anatoly Pugachev]

On Fri, Jul 3, 2020 at 6:58 PM Valentin Schneider
<valentin.schneider@arm.com> wrote:
>
> sparc64 hasn't needed to select this since commit:
>
>   ee6a9333fa58 ("sparc64: sparse irq")
>
> which got rid of the calls to __irq_set_preflow_handler() first installed
> by commit:
>
>   fcd8d4f49869 ("sparc: Use the new genirq functionality")
>
> Deselect this option.
>
> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
> ---
>  arch/sparc/Kconfig | 1 -
>  1 file changed, 1 deletion(-)
>
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index da515fdad83d..ed35760043e8 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -81,7 +81,6 @@ config SPARC64
>         select RTC_DRV_STARFIRE
>         select HAVE_PERF_EVENTS
>         select PERF_USE_VMALLOC
> -       select IRQ_PREFLOW_FASTEOI
>         select ARCH_HAVE_NMI_SAFE_CMPXCHG
>         select HAVE_C_RECORDMCOUNT
>         select HAVE_ARCH_AUDITSYSCALL


tried/tested this patch on my test sparc64 ldom , boots ok

[tip: irq/core] sparc64: Deselect IRQ_PREFLOW_FASTEOI

[tip-bot2 for Valentin Schneider]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     959f53bd90c3ac70e5481199c6159f6314f9f910
Gitweb:        https://git.kernel.org/tip/959f53bd90c3ac70e5481199c6159f6314f9f910
Author:        Valentin Schneider <valentin.schneider@arm.com>
AuthorDate:    Fri, 03 Jul 2020 16:56:44 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 04 Jul 2020 10:02:06 +02:00

sparc64: Deselect IRQ_PREFLOW_FASTEOI

sparc64 hasn't needed to select this since commit:

  ee6a9333fa58 ("sparc64: sparse irq")

which got rid of the calls to __irq_set_preflow_handler() first installed
by commit:

  fcd8d4f49869 ("sparc: Use the new genirq functionality")

Deselect this option.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Anatoly Pugachev <matorola@gmail.com> 
Link: https://lkml.kernel.org/r/20200703155645.29703-2-valentin.schneider@arm.com

---
 arch/sparc/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 5bf2dc1..76f4078 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -80,7 +80,6 @@ config SPARC64
 	select RTC_DRV_STARFIRE
 	select HAVE_PERF_EVENTS
 	select PERF_USE_VMALLOC
-	select IRQ_PREFLOW_FASTEOI
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
 	select HAVE_C_RECORDMCOUNT
 	select HAVE_ARCH_AUDITSYSCALL

[tip: irq/core] genirq: Remove preflow handler support

[tip-bot2 for Valentin Schneider]

The following commit has been merged into the irq/core branch of tip:

Commit-ID:     8fa88a88d573093868565a1afba43b5ae5b3a316
Gitweb:        https://git.kernel.org/tip/8fa88a88d573093868565a1afba43b5ae5b3a316
Author:        Valentin Schneider <valentin.schneider@arm.com>
AuthorDate:    Fri, 03 Jul 2020 16:56:45 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 04 Jul 2020 10:02:06 +02:00

genirq: Remove preflow handler support

That was put in place for sparc64, and blackfin also used it for some time;
sparc64 no longer uses those, and blackfin is dead.

As there are no more users, remove preflow handlers.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200703155645.29703-3-valentin.schneider@arm.com

---
 include/linux/irqdesc.h    | 15 ---------------
 include/linux/irqhandler.h |  1 -
 kernel/irq/Kconfig         |  4 ----
 kernel/irq/chip.c          | 13 -------------
 4 files changed, 33 deletions(-)

diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 8f2820c..5745491 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -22,7 +22,6 @@ struct pt_regs;
  * @irq_common_data:	per irq and chip data passed down to chip functions
  * @kstat_irqs:		irq stats per cpu
  * @handle_irq:		highlevel irq-events handler
- * @preflow_handler:	handler called before the flow handler (currently used by sparc)
  * @action:		the irq action chain
  * @status_use_accessors: status information
  * @core_internal_state__do_not_mess_with_it: core internal status information
@@ -58,9 +57,6 @@ struct irq_desc {
 	struct irq_data		irq_data;
 	unsigned int __percpu	*kstat_irqs;
 	irq_flow_handler_t	handle_irq;
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-	irq_preflow_handler_t	preflow_handler;
-#endif
 	struct irqaction	*action;	/* IRQ action list */
 	unsigned int		status_use_accessors;
 	unsigned int		core_internal_state__do_not_mess_with_it;
@@ -268,15 +264,4 @@ irq_set_lockdep_class(unsigned int irq, struct lock_class_key *lock_class,
 	}
 }
 
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-static inline void
-__irq_set_preflow_handler(unsigned int irq, irq_preflow_handler_t handler)
-{
-	struct irq_desc *desc;
-
-	desc = irq_to_desc(irq);
-	desc->preflow_handler = handler;
-}
-#endif
-
 #endif
diff --git a/include/linux/irqhandler.h b/include/linux/irqhandler.h
index 1e6f4e7..c30f454 100644
--- a/include/linux/irqhandler.h
+++ b/include/linux/irqhandler.h
@@ -10,6 +10,5 @@
 struct irq_desc;
 struct irq_data;
 typedef	void (*irq_flow_handler_t)(struct irq_desc *desc);
-typedef	void (*irq_preflow_handler_t)(struct irq_data *data);
 
 #endif
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 2051225..10a5aff 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -51,10 +51,6 @@ config GENERIC_IRQ_INJECTION
 config HARDIRQS_SW_RESEND
        bool
 
-# Preflow handler support for fasteoi (sparc64)
-config IRQ_PREFLOW_FASTEOI
-       bool
-
 # Edge style eoi based handler (cell)
 config IRQ_EDGE_EOI_HANDLER
        bool
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 41e7e37..75bbaa8 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -656,16 +656,6 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(handle_level_irq);
 
-#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
-static inline void preflow_handler(struct irq_desc *desc)
-{
-	if (desc->preflow_handler)
-		desc->preflow_handler(&desc->irq_data);
-}
-#else
-static inline void preflow_handler(struct irq_desc *desc) { }
-#endif
-
 static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
 {
 	if (!(desc->istate & IRQS_ONESHOT)) {
@@ -721,7 +711,6 @@ void handle_fasteoi_irq(struct irq_desc *desc)
 	if (desc->istate & IRQS_ONESHOT)
 		mask_irq(desc);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);
@@ -1231,7 +1220,6 @@ void handle_fasteoi_ack_irq(struct irq_desc *desc)
 	/* Start handling the irq */
 	desc->irq_data.chip->irq_ack(&desc->irq_data);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);
@@ -1281,7 +1269,6 @@ void handle_fasteoi_mask_irq(struct irq_desc *desc)
 	if (desc->istate & IRQS_ONESHOT)
 		mask_irq(desc);
 
-	preflow_handler(desc);
 	handle_irq_event(desc);
 
 	cond_unmask_eoi_irq(desc, chip);

Re: [PATCH 0/2] genirq: Kill preflow handlers

[Marc Zyngier]

Hi Valentin,

On 2020-07-03 16:56, Valentin Schneider wrote:
> Hi,
> 
> while strolling around the different flow handlers, I tried to make 
> sense of
> what preflow_handler() was about. Turns out no one uses those anymore, 
> but the
> genirq support has remained in place.

If we needed to reintroduce some form of preflow handler, we'd try and
do it using hierarchical irqchips, if at all possible.

> 
> Unless we can see another user of those in the near future, this seems 
> like as
> good a time as any for a little housecleaning.
> 
> - Patch 1 simply deselects the (unexploited) preflow Kconfig for 
> sparc64
> - Patch 2 is the actual cleanup
> 
> Cheers,
> Valentin
> 
> Valentin Schneider (2):
>   sparc64: Deselect IRQ_PREFLOW_FASTEOI
>   genirq: Remove preflow handler support
> 
>  arch/sparc/Kconfig         |  1 -
>  include/linux/irqdesc.h    | 15 ---------------
>  include/linux/irqhandler.h |  1 -
>  kernel/irq/Kconfig         |  4 ----
>  kernel/irq/chip.c          | 13 -------------
>  5 files changed, 34 deletions(-)

For the whole series, and assuming that there is no regression
(can't imagine any for unused code):

Reviewed-by: Marc Zyngier <maz@kernel.org>

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH 0/2] genirq: Kill preflow handlers

[Valentin Schneider]

Hi Marc,

On 04/07/20 10:48, Marc Zyngier wrote:
> Hi Valentin,
>
> On 2020-07-03 16:56, Valentin Schneider wrote:
>> Hi,
>>
>> while strolling around the different flow handlers, I tried to make
>> sense of
>> what preflow_handler() was about. Turns out no one uses those anymore,
>> but the
>> genirq support has remained in place.
>
> If we needed to reintroduce some form of preflow handler, we'd try and
> do it using hierarchical irqchips, if at all possible.

Right, that does sound like the most sensible approach. If I got my history
right, the preflow handlers saw the light of day before hierarchical
domains did, which I suppose is a reason why it wasn't done that way back
then.

>
>>
>> Unless we can see another user of those in the near future, this seems
>> like as
>> good a time as any for a little housecleaning.
>>
>> - Patch 1 simply deselects the (unexploited) preflow Kconfig for
>> sparc64
>> - Patch 2 is the actual cleanup
>>
>> Cheers,
>> Valentin
>>
>> Valentin Schneider (2):
>>   sparc64: Deselect IRQ_PREFLOW_FASTEOI
>>   genirq: Remove preflow handler support
>>
>>  arch/sparc/Kconfig         |  1 -
>>  include/linux/irqdesc.h    | 15 ---------------
>>  include/linux/irqhandler.h |  1 -
>>  kernel/irq/Kconfig         |  4 ----
>>  kernel/irq/chip.c          | 13 -------------
>>  5 files changed, 34 deletions(-)
>
> For the whole series, and assuming that there is no regression
> (can't imagine any for unused code):
>
> Reviewed-by: Marc Zyngier <maz@kernel.org>
>

Thanks!

> Thanks,
>
>          M.

Re: [PATCH 1/2] sparc64: Deselect IRQ_PREFLOW_FASTEOI

[David Miller]

From: Valentin Schneider <valentin.schneider@arm.com>
Date: Fri,  3 Jul 2020 16:56:44 +0100

> sparc64 hasn't needed to select this since commit:
> 
>   ee6a9333fa58 ("sparc64: sparse irq")
> 
> which got rid of the calls to __irq_set_preflow_handler() first installed
> by commit:
> 
>   fcd8d4f49869 ("sparc: Use the new genirq functionality")
> 
> Deselect this option.
> 
> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>

Acked-by: David S. Miller <davem@davemloft.net>