linux-kernel - Re: [PATCH v9 9/9] locking: Switch to _irq_{disable,enable}() variants in cleanup guards

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Message-ID: <tencent_D533AC8B48B52FF3359EE89ACC69D32FDA09@qq.com>
Date: Sat, 5 Apr 2025 16:55:06 +0800
From: Guangbo Cui <2407018371@...com>
To: lyude@...hat.com
Cc: boqun.feng@...il.com, linux-kernel@...r.kernel.org, longman@...hat.com,
	mingo@...hat.com, peterz@...radead.org,
	rust-for-linux@...r.kernel.org, tglx@...utronix.de, will@...nel.org
Subject: Re: [PATCH v9 9/9] locking: Switch to _irq_{disable,enable}()
 variants in cleanup guards

On Sat, Apr 05, 2025 at 04:25:11PM +0800, Guangbo Cui wrote:
> >  include/linux/spinlock.h | 26 ++++++++++++--------------
> >  1 file changed, 12 insertions(+), 14 deletions(-)
> > 
> > diff --git a/include/linux/spinlock.h b/include/linux/spinlock.h
> > index 897114d60cfd4..764c9fd797d0e 100644
> > --- a/include/linux/spinlock.h
> > +++ b/include/linux/spinlock.h
> > @@ -605,18 +605,17 @@ DEFINE_LOCK_GUARD_1(raw_spinlock_nested, raw_spinlock_t,
> >  		      raw_spin_unlock(_T->lock))
> >  
> >  DEFINE_LOCK_GUARD_1(raw_spinlock_irq, raw_spinlock_t,
> > -		      raw_spin_lock_irq(_T->lock),
> > -		      raw_spin_unlock_irq(_T->lock))
> > +		      raw_spin_lock_irq_disable(_T->lock),
> > +		      raw_spin_unlock_irq_enable(_T->lock))
> >  
> > -DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq(_T->lock))
> > +DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irq, _try, raw_spin_trylock_irq_disable(_T->lock))
> >  
> >  DEFINE_LOCK_GUARD_1(raw_spinlock_irqsave, raw_spinlock_t,
> > -		      raw_spin_lock_irqsave(_T->lock, _T->flags),
> > -		      raw_spin_unlock_irqrestore(_T->lock, _T->flags),
> > -		      unsigned long flags)
> > +		      raw_spin_lock_irq_disable(_T->lock),
> > +		      raw_spin_unlock_irq_enable(_T->lock))
> >  
> >  DEFINE_LOCK_GUARD_1_COND(raw_spinlock_irqsave, _try,
> > -			   raw_spin_trylock_irqsave(_T->lock, _T->flags))
> > +			   raw_spin_trylock_irq_disable(_T->lock))
> 
> It seems that the `raw_spin_trylock_irq_disable` function is missing from
> spinlock_rt.h, which will lead to a build failure when compiling with 
> PREEMPT_RT enabled.
>

Sorry, my fault, I mean the `spin_trylock_irq_disable` function.

> DEFINE_LOCK_GUARD_1_COND(spinlock_irq, _try,
> 			   spin_trylock_irq_disable(_T->lock))
> 
> DEFINE_LOCK_GUARD_1_COND(spinlock_irqsave, _try,
>			   spin_trylock_irq_disable(_T->lock))

Not sure if I wrote it correctly, but you know what I mean.

diff --git a/include/linux/spinlock_rt.h b/include/linux/spinlock_rt.h
index 6ea08fafa6d7..4a65da35b211 100644
--- a/include/linux/spinlock_rt.h
+++ b/include/linux/spinlock_rt.h
@@ -151,6 +151,11 @@ static __always_inline void spin_unlock_irqrestore(spinlock_t *lock,
 	__locked;					\
 })
 
+static __always_inline int spin_trylock_irq_disable(spinlock_t *lock)
+{
+	return rt_spin_trylock(lock);
+}
+
 #define spin_is_contended(lock)		(((void)(lock), 0))
 
 static inline int spin_is_locked(spinlock_t *lock)
-- 

Best regards,
Guangbo Cui