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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf@vger.kernel.org, andrii@kernel.org, memxor@gmail.com,
	akpm@linux-foundation.org, peterz@infradead.org, vbabka@suse.cz,
	rostedt@goodmis.org, houtao1@huawei.com, hannes@cmpxchg.org,
	shakeel.butt@linux.dev, mhocko@suse.com, willy@infradead.org,
	tglx@linutronix.de, tj@kernel.org, linux-mm@kvack.org,
	kernel-team@fb.com
Subject: Re: [PATCH bpf-next v2 3/6] locking/local_lock: Introduce
 local_trylock_irqsave()
Message-ID: <20241212151529.oPNxM6JC@linutronix.de>
References: <20241210023936.46871-1-alexei.starovoitov@gmail.com>
 <20241210023936.46871-4-alexei.starovoitov@gmail.com>
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In-Reply-To: <20241210023936.46871-4-alexei.starovoitov@gmail.com>

> diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h
> index 8dd71fbbb6d2..2c0f8a49c2d0 100644
> --- a/include/linux/local_lock_internal.h
> +++ b/include/linux/local_lock_internal.h
> @@ -148,6 +163,14 @@ typedef spinlock_t local_lock_t;
>  		__local_lock(lock);				\
>  	} while (0)
>  
> +#define __local_trylock_irqsave(lock, flags)			\
> +	({							\
> +		typecheck(unsigned long, flags);		\
> +		flags = 0;					\
> +		migrate_disable();				\
> +		spin_trylock(this_cpu_ptr((__lock)));		\

You should probably do a migrate_enable() here if the trylock fails.

> +	})
> +
>  #define __local_unlock(__lock)					\
>  	do {							\
>  		spin_unlock(this_cpu_ptr((__lock)));		\

Sebastian