From patchwork Mon Oct 7 10:14:15 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Schmidt X-Patchwork-Id: 13824416 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 813751B3F1F for ; Mon, 7 Oct 2024 10:14:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728296084; cv=none; b=ad/EiAc01qQ/6HRlulRJ4hsMrSfTrsBSV2prtArnKbYi0z57YlwVPYF29qVo/yC1mreFk0R2rkfAmsM9NlhL3jxk6cPkzfgPTox9/S4VYiZXnBO6RGfuylLRg2KZTis4muixm4iURHtGVlKI0bZj/Ba8SKFyJYhEO6mBpU86FQM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1728296084; c=relaxed/simple; bh=/e87TIRhMNaoB0p1RReT7keK7xxF1cuUqXVWKLEd0oY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RUU+fj7IhEDf4dkT1/tB89MCXaLSIGmmA/JTiPRIxye2fsFjYBO81ItIUvHAfr2kNzJ+OLPhL/UpCzrbCBt2po4wUvH779cdPTCSuEOhiey9jS4voYSlLU74M5EgTaYkEwkt6FWfvDF+JTKmAqvIC/6uaFqgbnSRQijRJVKM9eA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aNzXnKlk; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aNzXnKlk" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728296080; 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; bh=3IjXN8FnwsXp6zfExtH8ltC2YeZMQ8iJiIBUY0fo+fE=; b=aNzXnKlklUweou6WEExbvuaZiLj5ri83HjVGPsdjeTDlq4RfGvZcJpvLS7UwHGC1OwcRh4 BZuL4N9Vh0Gz8KCyTmff5cMPF6/aBRcmbMCFh66ReTBRPA/br41RMZfqudEkFF2fx3LdR4 yJG9SJABEE5RH0ThXuyDAbToJQcvidk= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-49-oC1ZLCL6NUOrNr405DA1fA-1; Mon, 07 Oct 2024 06:14:37 -0400 X-MC-Unique: oC1ZLCL6NUOrNr405DA1fA-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 13C1F19560B7; Mon, 7 Oct 2024 10:14:35 +0000 (UTC) Received: from localhost.localdomain (unknown [10.45.225.47]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8AF31300018D; Mon, 7 Oct 2024 10:14:31 +0000 (UTC) From: Michal Schmidt To: Lai Jiangshan , "Paul E. McKenney" , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , "Uladzislau Rezki (Sony)" Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] rcu/srcutiny: don't return before reenabling preemption Date: Mon, 7 Oct 2024 12:14:15 +0200 Message-ID: <20241007101415.466155-1-mschmidt@redhat.com> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Code after the return statement is dead. Enable preemption before returning from srcu_drive_gp(). This will be important when/if PREEMPT_AUTO (lazy resched) gets merged. Fixes: 65b4a59557f6 ("srcu: Make Tiny SRCU explicitly disable preemption") Signed-off-by: Michal Schmidt Reviewed-by: Paul E. McKenney --- kernel/rcu/srcutiny.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 549c03336ee9..4dcbf8aa80ff 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -122,8 +122,8 @@ void srcu_drive_gp(struct work_struct *wp) ssp = container_of(wp, struct srcu_struct, srcu_work); preempt_disable(); // Needed for PREEMPT_AUTO if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max))) { - return; /* Already running or nothing to do. */ preempt_enable(); + return; /* Already running or nothing to do. */ } /* Remove recently arrived callbacks and wait for readers. */