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[tip:irq/core] genirq: Use a common macro to go through the actions list

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  [tip:irq/core] genirq:   Use a common macro to go through the actions list tip-bot for Daniel Lezcano <tipbot@zytor.com> - 2016-02-08 11:50 +0100
    Re: [tip:irq/core] genirq: Use a common macro to go through the  actions list Daniel Lezcano <daniel.lezcano@linaro.org> - 2016-02-08 16:30 +0100

#1328913 — [tip:irq/core] genirq: Use a common macro to go through the actions list

Commit-ID:  aff62cf66ad6065ce04fc3454a11ec19714537fb
Gitweb:     http://git.kernel.org/tip/aff62cf66ad6065ce04fc3454a11ec19714537fb
Author:     Daniel Lezcano <daniel.lezcano@linaro.org>
AuthorDate: Thu, 14 Jan 2016 10:54:13 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Mon, 8 Feb 2016 11:45:21 +0100

genirq: Use a common macro to go through the actions list

The irq code browses the list of actions differently to inspect the element
one by one. Even if it is not a problem, for the sake of consistent code,
provide a macro similar to for_each_irq_desc in order to have the same loop to
go through the actions list and use it in the code.

[ tglx: Renamed the macro ]

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: http://lkml.kernel.org/r/1452765253-31148-1-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/irq/handle.c    | 5 ++---
 kernel/irq/internals.h | 3 +++
 kernel/irq/manage.c    | 8 +++-----
 kernel/irq/proc.c      | 2 +-
 kernel/irq/spurious.c  | 4 +---
 5 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 57bff78..67534d0 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -136,10 +136,9 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
 {
 	irqreturn_t retval = IRQ_NONE;
 	unsigned int flags = 0, irq = desc->irq_data.irq;
-	struct irqaction *action = desc->action;
+	struct irqaction *action;
 
-	/* action might have become NULL since we dropped the lock */
-	while (action) {
+	for_each_action_of_desc(desc, action) {
 		irqreturn_t res;
 
 		trace_irq_handler_entry(irq, action);
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index fcab63c..eab521f 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -131,6 +131,9 @@ static inline void chip_bus_sync_unlock(struct irq_desc *desc)
 #define IRQ_GET_DESC_CHECK_GLOBAL	(_IRQ_DESC_CHECK)
 #define IRQ_GET_DESC_CHECK_PERCPU	(_IRQ_DESC_CHECK | _IRQ_DESC_PERCPU)
 
+#define for_each_action_of_desc(desc, act)			\
+	for (act = desc->act; act; act = act->next)
+
 struct irq_desc *
 __irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
 		    unsigned int check);
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 8411872..3ddd229 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -144,13 +144,11 @@ int irq_can_set_affinity(unsigned int irq)
  */
 void irq_set_thread_affinity(struct irq_desc *desc)
 {
-	struct irqaction *action = desc->action;
+	struct irqaction *action;
 
-	while (action) {
+	for_each_action_of_desc(desc, action)
 		if (action->thread)
 			set_bit(IRQTF_AFFINITY, &action->thread_flags);
-		action = action->next;
-	}
 }
 
 #ifdef CONFIG_GENERIC_PENDING_IRQ
@@ -994,7 +992,7 @@ void irq_wake_thread(unsigned int irq, void *dev_id)
 		return;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	for (action = desc->action; action; action = action->next) {
+	for_each_action_of_desc(desc, action) {
 		if (action->dev_id == dev_id) {
 			if (action->thread)
 				__irq_wake_thread(desc, action);
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index a2c02fd..4e1b947 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -291,7 +291,7 @@ static int name_unique(unsigned int irq, struct irqaction *new_action)
 	int ret = 1;
 
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	for (action = desc->action ; action; action = action->next) {
+	for_each_action_of_desc(desc, action) {
 		if ((action != new_action) && action->name &&
 				!strcmp(new_action->name, action->name)) {
 			ret = 0;
diff --git a/kernel/irq/spurious.c b/kernel/irq/spurious.c
index 3214417..5707f97 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -211,14 +211,12 @@ static void __report_bad_irq(struct irq_desc *desc, irqreturn_t action_ret)
 	 * desc->lock here. See synchronize_irq().
 	 */
 	raw_spin_lock_irqsave(&desc->lock, flags);
-	action = desc->action;
-	while (action) {
+	for_each_action_of_desc(desc, action) {
 		printk(KERN_ERR "[<%p>] %pf", action->handler, action->handler);
 		if (action->thread_fn)
 			printk(KERN_CONT " threaded [<%p>] %pf",
 					action->thread_fn, action->thread_fn);
 		printk(KERN_CONT "\n");
-		action = action->next;
 	}
 	raw_spin_unlock_irqrestore(&desc->lock, flags);
 }

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#1329180 — Re: [tip:irq/core] genirq: Use a common macro to go through the actions list

On 02/08/2016 11:48 AM, tip-bot for Daniel Lezcano wrote:
> Commit-ID:  aff62cf66ad6065ce04fc3454a11ec19714537fb
> Gitweb:     http://git.kernel.org/tip/aff62cf66ad6065ce04fc3454a11ec19714537fb
> Author:     Daniel Lezcano <daniel.lezcano@linaro.org>
> AuthorDate: Thu, 14 Jan 2016 10:54:13 +0100
> Committer:  Thomas Gleixner <tglx@linutronix.de>
> CommitDate: Mon, 8 Feb 2016 11:45:21 +0100
>
> genirq: Use a common macro to go through the actions list
>
> The irq code browses the list of actions differently to inspect the element
> one by one. Even if it is not a problem, for the sake of consistent code,
> provide a macro similar to for_each_irq_desc in order to have the same loop to
> go through the actions list and use it in the code.
>
> [ tglx: Renamed the macro ]
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Link: http://lkml.kernel.org/r/1452765253-31148-1-git-send-email-daniel.lezcano@linaro.org
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---
>   kernel/irq/handle.c    | 5 ++---
>   kernel/irq/internals.h | 3 +++
>   kernel/irq/manage.c    | 8 +++-----
>   kernel/irq/proc.c      | 2 +-
>   kernel/irq/spurious.c  | 4 +---
>   5 files changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
> index 57bff78..67534d0 100644
> --- a/kernel/irq/handle.c
> +++ b/kernel/irq/handle.c
> @@ -136,10 +136,9 @@ irqreturn_t handle_irq_event_percpu(struct irq_desc *desc)
>   {
>   	irqreturn_t retval = IRQ_NONE;
>   	unsigned int flags = 0, irq = desc->irq_data.irq;
> -	struct irqaction *action = desc->action;
> +	struct irqaction *action;
>
> -	/* action might have become NULL since we dropped the lock */
> -	while (action) {
> +	for_each_action_of_desc(desc, action) {
>   		irqreturn_t res;
>
>   		trace_irq_handler_entry(irq, action);

The merge lost the removal of:

action = action->next;

resulting to the NULL pointer dereference bug spotted by 01.org.

Do you want me to resend a new patch ?

   -- Daniel


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