[PATCH -next v6 4/8] arm64: entry: Rework arm64_preempt_schedule_irq()

[Jinjie Ruan <ruanjinjie@xxxxxxxxxx>]

The generic entry code has the form:

| raw_irqentry_exit_cond_resched()
| {
|       if (!preempt_count()) {
|               ...
|               if (need_resched())
|                       preempt_schedule_irq();
|       }
| }

In preparation for moving arm64 over to the generic entry code, align
the structure of the arm64 code with raw_irqentry_exit_cond_resched() from
the generic entry code.

Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
---
v6:
- Update the commit message.
---
 arch/arm64/kernel/entry-common.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/entry-common.c b/arch/arm64/kernel/entry-common.c
index 8e597d32433d..94e4132213ce 100644
--- a/arch/arm64/kernel/entry-common.c
+++ b/arch/arm64/kernel/entry-common.c
@@ -289,10 +289,10 @@ 
DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
 #define need_irq_preemption()  (IS_ENABLED(CONFIG_PREEMPTION))
 #endif
 
-static void __sched arm64_preempt_schedule_irq(void)
+static inline bool arm64_preempt_schedule_irq(void)
 {
        if (!need_irq_preemption())
-               return;
+               return false;
 
        /*
         * Note: thread_info::preempt_count includes both thread_info::count
@@ -300,7 +300,7 @@ static void __sched arm64_preempt_schedule_irq(void)
         * preempt_count().
         */
        if (READ_ONCE(current_thread_info()->preempt_count) != 0)
-               return;
+               return false;
 
        /*
         * DAIF.DA are cleared at the start of IRQ/FIQ handling, and when GIC
@@ -309,7 +309,7 @@ static void __sched arm64_preempt_schedule_irq(void)
         * DAIF we must have handled an NMI, so skip preemption.
         */
        if (system_uses_irq_prio_masking() && read_sysreg(daif))
-               return;
+               return false;
 
        /*
         * Preempting a task from an IRQ means we leave copies of PSTATE
@@ -319,8 +319,10 @@ static void __sched arm64_preempt_schedule_irq(void)
         * Only allow a task to be preempted once cpufeatures have been
         * enabled.
         */
-       if (system_capabilities_finalized())
-               preempt_schedule_irq();
+       if (!system_capabilities_finalized())
+               return false;
+
+       return true;
 }
 
 static void do_interrupt_handler(struct pt_regs *regs,
@@ -591,7 +593,8 @@ static __always_inline void __el1_irq(struct pt_regs *regs,
        do_interrupt_handler(regs, handler);
        irq_exit_rcu();
 
-       arm64_preempt_schedule_irq();
+       if (arm64_preempt_schedule_irq())
+               preempt_schedule_irq();
 
        exit_to_kernel_mode(regs, state);
 }
-- 
2.34.1