From nobody Sun Nov 24 08:41:41 2024 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 05795202625; Wed, 6 Nov 2024 14:59:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730905168; cv=none; b=QVktJGZZ4X9aNgXoCOCZuc5o7HsR1bvb/RWQgBEezd7N1TMncIRMzRkJEw4OEpkObz74HHnz54bTwD5gB1enD5CkzMlJOnV9hlX2b9w5sJSnfEGnWoFnqm822Q5gjCkUHVymHV56Ib4T7Mjv9+TKZa+hM1TC+KELJt50Vwof8SA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730905168; c=relaxed/simple; bh=qA/c0N3rIn1d+527roOwF7bl5h7TXeVRuH3DxgNRebw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=pf2sAHjoCUhREIK2chhTSiRqY6TcscfdTLw9vLhpW9JjvbsXteXLGUSqknPHUXQIffRh7JhMvwYxgySUY4Cyor/IeRYO57kOLWj8wGlYh4d/g2F7sxmO18woeI6g/EfbLV6wV6rU887WaVvDXu0OOGfvHqFTvF24YXUDryjbx8o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kiq8Et49; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kiq8Et49" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0C369C4CEC6; Wed, 6 Nov 2024 14:59:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1730905166; bh=qA/c0N3rIn1d+527roOwF7bl5h7TXeVRuH3DxgNRebw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kiq8Et49D6w50kLceRxq1pVCsNKk+lrWWZpW+ScNk4nVPEwlWESeMhuHe4c5dLEK4 RvXRaXOTbrPgOgN/lCXkF3kiPmjbWrOy6lv5BJeiMs+unBf6Z4ybnmPvFHa1NLrJ4B TQ/MN6SksZjvxa1f9jQhXGCtqBMmbhfllIROHvvrmGqWRuJiuDaPzFrqPhY6aKPT8+ WKJzYDngpAxPXmc3txEbpQIltaooKSIYjhpy+1wFH5Nk0WBXdJQd7XcJ6Fg7XBZ8dP G9MvZjix/EGr4vhrU4p/2Gr2LgECwlfN5+VDyacYmpa9FTkgXpijBoMz72z+tuT/uz WVhiUsVB6q86g== From: Frederic Weisbecker To: LKML Cc: "Paul E. McKenney" , Boqun Feng , Joel Fernandes , Josh Triplett , Lai Jiangshan , Mathieu Desnoyers , Neeraj Upadhyay , Steven Rostedt , Uladzislau Rezki , Zqiang , rcu , Kent Overstreet , Frederic Weisbecker Subject: [PATCH 3/8] rcu: Permit start_poll_synchronize_rcu*() with interrupts disabled Date: Wed, 6 Nov 2024 15:59:06 +0100 Message-ID: <20241106145911.35503-4-frederic@kernel.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20241106145911.35503-1-frederic@kernel.org> References: <20241106145911.35503-1-frederic@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Paul E. McKenney" The header comment for both start_poll_synchronize_rcu() and start_poll_synchronize_rcu_full() state that interrupts must be enabled when calling these two functions, and there is a lockdep assertion in start_poll_synchronize_rcu_common() enforcing this restriction. However, there is no need for this restrictions, as can be seen in call_rcu(), which does wakeups when interrupts are disabled. This commit therefore removes the lockdep assertion and the comments. Reported-by: Kent Overstreet Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker --- kernel/rcu/tree.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 38b121a77366..13829cf38f52 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4194,7 +4194,6 @@ static void start_poll_synchronize_rcu_common(void) struct rcu_data *rdp; struct rcu_node *rnp; =20 - lockdep_assert_irqs_enabled(); local_irq_save(flags); rdp =3D this_cpu_ptr(&rcu_data); rnp =3D rdp->mynode; @@ -4219,9 +4218,6 @@ static void start_poll_synchronize_rcu_common(void) * grace period has elapsed in the meantime. If the needed grace period * is not already slated to start, notifies RCU core of the need for that * grace period. - * - * Interrupts must be enabled for the case where it is necessary to awaken - * the grace-period kthread. */ unsigned long start_poll_synchronize_rcu(void) { @@ -4242,9 +4238,6 @@ EXPORT_SYMBOL_GPL(start_poll_synchronize_rcu); * grace period (whether normal or expedited) has elapsed in the meantime. * If the needed grace period is not already slated to start, notifies * RCU core of the need for that grace period. - * - * Interrupts must be enabled for the case where it is necessary to awaken - * the grace-period kthread. */ void start_poll_synchronize_rcu_full(struct rcu_gp_oldstate *rgosp) { --=20 2.46.0