From patchwork Fri May 3 18:25:06 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 13653314 X-Patchwork-Delegate: kuba@kernel.org Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 49802158864; Fri, 3 May 2024 18:30:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714761010; cv=none; b=P0H0UbZjfxvwt3DjIz/Y4I3JOr/JTHRncMPhk7Eat4yGXiuR8flMSPNlAQD8TrBVG53QoXimI4rToNiswQhKKTMR+iISLDeuyBlMi8k37hEim5+5inAzt1bxMrKr+FgczFEJyHAwoKungbr93JU4oJ+jt2c5JPP74d/8HSJ/nNw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714761010; c=relaxed/simple; bh=MZehckFQCZ1u/y7PloNAo3YtUp4b7HlyP3SBCD07p70=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gApDYJ29j3jGWaZVbG/5cYmMUhTvM92s9SDwNXh68+odupimxvkEe4L9bcRphguhH4siLc2ZeOmXCOKSdp+P0ujhnsjBuiMEqWQZvnFE+syP2IK5g6EgKL7/JoMC8c+CSJqwJIgYdrFw8NzdotJCIMemINGPHlxHFXQ8o//eksE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=vtZGc5L9; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=P10KOxGy; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="vtZGc5L9"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="P10KOxGy" From: Sebastian Andrzej Siewior DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1714761006; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2wq7pOwmFszJxpMJEiSdFQognKwP7zLDfT8VaO1TStI=; b=vtZGc5L98qmbPquh7Z+gsbsv5TolCzpKxbdmLaMh3VhY0YbUx3eyfeEMFay3ULMEvZDqKV rHnEpc8Xv2w0g62ncWJ2rfmsx3o7Vy+u9kwANTLENb2nsGp65bDPU3LXoXGWkhdf8nDhqs cBL5ygaTaCCtIVNjnw5UwYzHygxwnKvVkZTCKPrwQqYd7JAa0o198++8/5u//7E1W2zMZw FXjApyID1JMQkiEggkd/B6M+TbcmFAzMLkvOy2X0gAdTDj2KsBvSWWMvZGnuslDmeIs5lD FA3VuMEmCntPt1Zuvfn92qntKOnDt0JFYCS+li/26/FMLkUtDmJg9xy1ejJwWA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1714761006; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2wq7pOwmFszJxpMJEiSdFQognKwP7zLDfT8VaO1TStI=; b=P10KOxGyLneL8XFy/dt/maTprc9Rkl2YrgbmoGMDTLPvOtP+Cp6zhB21eDvxgs2cEWcieo frvQWDKpetzzJPBg== To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: "David S. Miller" , Boqun Feng , Daniel Borkmann , Eric Dumazet , Frederic Weisbecker , Ingo Molnar , Jakub Kicinski , Paolo Abeni , Peter Zijlstra , Thomas Gleixner , Waiman Long , Will Deacon , Sebastian Andrzej Siewior Subject: [PATCH net-next 02/15] locking/local_lock: Add local nested BH locking infrastructure. Date: Fri, 3 May 2024 20:25:06 +0200 Message-ID: <20240503182957.1042122-3-bigeasy@linutronix.de> In-Reply-To: <20240503182957.1042122-1-bigeasy@linutronix.de> References: <20240503182957.1042122-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Add local_lock_nested_bh() locking. It is based on local_lock_t and the naming follows the preempt_disable_nested() example. For !PREEMPT_RT + !LOCKDEP it is a per-CPU annotation for locking assumptions based on local_bh_disable(). The macro is optimized away during compilation. For !PREEMPT_RT + LOCKDEP the local_lock_nested_bh() is reduced to the usual lock-acquire plus lockdep_assert_in_softirq() - ensuring that BH is disabled. For PREEMPT_RT local_lock_nested_bh() acquires the specified per-CPU lock. It does not disable CPU migration because it relies on local_bh_disable() disabling CPU migration. With LOCKDEP it performans the usual lockdep checks as with !PREEMPT_RT. Due to include hell the softirq check has been moved spinlock.c. The intention is to use this locking in places where locking of a per-CPU variable relies on BH being disabled. Instead of treating disabled bottom halves as a big per-CPU lock, PREEMPT_RT can use this to reduce the locking scope to what actually needs protecting. A side effect is that it also documents the protection scope of the per-CPU variables. Signed-off-by: Sebastian Andrzej Siewior --- include/linux/local_lock.h | 10 ++++++++++ include/linux/local_lock_internal.h | 31 +++++++++++++++++++++++++++++ include/linux/lockdep.h | 3 +++ kernel/locking/spinlock.c | 8 ++++++++ 4 files changed, 52 insertions(+) diff --git a/include/linux/local_lock.h b/include/linux/local_lock.h index 82366a37f4474..091dc0b6bdfb9 100644 --- a/include/linux/local_lock.h +++ b/include/linux/local_lock.h @@ -62,4 +62,14 @@ DEFINE_LOCK_GUARD_1(local_lock_irqsave, local_lock_t __percpu, local_unlock_irqrestore(_T->lock, _T->flags), unsigned long flags) +#define local_lock_nested_bh(_lock) \ + __local_lock_nested_bh(_lock) + +#define local_unlock_nested_bh(_lock) \ + __local_unlock_nested_bh(_lock) + +DEFINE_GUARD(local_lock_nested_bh, local_lock_t __percpu*, + local_lock_nested_bh(_T), + local_unlock_nested_bh(_T)) + #endif diff --git a/include/linux/local_lock_internal.h b/include/linux/local_lock_internal.h index 975e33b793a77..8dd71fbbb6d2b 100644 --- a/include/linux/local_lock_internal.h +++ b/include/linux/local_lock_internal.h @@ -62,6 +62,17 @@ do { \ local_lock_debug_init(lock); \ } while (0) +#define __spinlock_nested_bh_init(lock) \ +do { \ + static struct lock_class_key __key; \ + \ + debug_check_no_locks_freed((void *)lock, sizeof(*lock));\ + lockdep_init_map_type(&(lock)->dep_map, #lock, &__key, \ + 0, LD_WAIT_CONFIG, LD_WAIT_INV, \ + LD_LOCK_NORMAL); \ + local_lock_debug_init(lock); \ +} while (0) + #define __local_lock(lock) \ do { \ preempt_disable(); \ @@ -98,6 +109,15 @@ do { \ local_irq_restore(flags); \ } while (0) +#define __local_lock_nested_bh(lock) \ + do { \ + lockdep_assert_in_softirq(); \ + local_lock_acquire(this_cpu_ptr(lock)); \ + } while (0) + +#define __local_unlock_nested_bh(lock) \ + local_lock_release(this_cpu_ptr(lock)) + #else /* !CONFIG_PREEMPT_RT */ /* @@ -138,4 +158,15 @@ typedef spinlock_t local_lock_t; #define __local_unlock_irqrestore(lock, flags) __local_unlock(lock) +#define __local_lock_nested_bh(lock) \ +do { \ + lockdep_assert_in_softirq_func(); \ + spin_lock(this_cpu_ptr(lock)); \ +} while (0) + +#define __local_unlock_nested_bh(lock) \ +do { \ + spin_unlock(this_cpu_ptr((lock))); \ +} while (0) + #endif /* CONFIG_PREEMPT_RT */ diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 08b0d1d9d78b7..3f5a551579cc9 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -600,6 +600,8 @@ do { \ (!in_softirq() || in_irq() || in_nmi())); \ } while (0) +extern void lockdep_assert_in_softirq_func(void); + #else # define might_lock(lock) do { } while (0) # define might_lock_read(lock) do { } while (0) @@ -613,6 +615,7 @@ do { \ # define lockdep_assert_preemption_enabled() do { } while (0) # define lockdep_assert_preemption_disabled() do { } while (0) # define lockdep_assert_in_softirq() do { } while (0) +# define lockdep_assert_in_softirq_func() do { } while (0) #endif #ifdef CONFIG_PROVE_RAW_LOCK_NESTING diff --git a/kernel/locking/spinlock.c b/kernel/locking/spinlock.c index 8475a0794f8c5..438c6086d540e 100644 --- a/kernel/locking/spinlock.c +++ b/kernel/locking/spinlock.c @@ -413,3 +413,11 @@ notrace int in_lock_functions(unsigned long addr) && addr < (unsigned long)__lock_text_end; } EXPORT_SYMBOL(in_lock_functions); + +#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_PREEMPT_RT) +void notrace lockdep_assert_in_softirq_func(void) +{ + lockdep_assert_in_softirq(); +} +EXPORT_SYMBOL(lockdep_assert_in_softirq_func); +#endif