From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f201.google.com (mail-pl1-f201.google.com [209.85.214.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 791591CAA90 for ; Thu, 10 Apr 2025 15:51:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744300281; cv=none; b=DtXrabzyyS6gtqZWrAcPAEsuHLdQcZRJKPEP/Z7wwQDsbvBLjYYNqEULl0dKOGuc0IyI1G8Ja3V/Ac1q2nUlKH8ihaVwydNJxxa03cB8097HlswsdYuf/XaWJSlTTI8lSdJF3/JiHZ2R74h1g+zFl6GwjtgwEChGbdVVPjWaMEY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744300281; c=relaxed/simple; bh=I1HL4EhttE881MicAtF32b66FddNBn0rz1b+bJ5vSpI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=q9D/lVgd5G0rbkxcKvUSzgTxvjY0+y2DmvoMmD7BuRdisCToW3rEC32qsCpeIgkzpsXWg2wHcpSjiaRMbduSuH+KJdh3wsqRtflvLIqHun2DwfXO1kTR8Mg/mqFjeuGNHak8NR5ppIfNd/u5Gm7wzLcuXdAt6opyv3Y4HZTGuoI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=f4Q1eHLj; arc=none smtp.client-ip=209.85.214.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--seanjc.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="f4Q1eHLj" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-22aa75e6653so7870515ad.0 for ; Thu, 10 Apr 2025 08:51:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1744300280; x=1744905080; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=WI+w75MsGfdj1Z+7uV4Y8gvQFBHXDpFpnvwgAEL/2AQ=; b=f4Q1eHLjh06cqU5LbO2nDLH4y0Nqn2CxPLF9B7KXvr3Oah+uv5JxMlfwnd06rHn0RF v4tfeUyir/NIhFOFF/8TE3eYn0sRmf/DVG7q8CepzReFXmZQo9/XKenVGQsi+0HNQxKl 8+le6Q02vjqRC86c59+NjkjGruwYEJKsmij41kkea1veoMr16f7fApLd1ecglfugocaU NSYKUhKdGvI2BZJXBLlwNuuS6adRbcInX0IOfWyFx+QhJwUsop3boOHbK8PlOy202Ssx M5EfAFqTzBnc/E6ElNIRtfLKRA2ftflhh4Xel6BaBmQE/ckwtlNX5rb/G2UdjYhOIXAd SXag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1744300280; x=1744905080; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=WI+w75MsGfdj1Z+7uV4Y8gvQFBHXDpFpnvwgAEL/2AQ=; b=C18CNOWLIJ7y2kSQhShNuQG+dp9JUtz4C65CXEnwSu0hztSH7QT0AWHxZPNu8cPcE8 AMSQAMiq8sWCuiryOPOPS/QKWs5cj39959SczY+n4euQl5O8lT3xtpZ0NWXZLiY+4Jgl t83vCekY7upPr/iFIK3fUGCtx11uugzzyA3DPZWMrcaX0gUvYDkGvMy7Wun2PcgrOfC5 OG2ZKKZij9en4RCnkkPqBoJ9FOauHteIk/5UT/ZII7PV4or4e9LaJV6Fgy6EBMEhleU7 deD49eOY68p7yJ1fJTbqA2/TP98oJ/bM/0HYugvt3N6LRRlTSRNl5w+VDxFCfQRah+du OR1A== X-Forwarded-Encrypted: i=1; AJvYcCUHM88Ncl7DKUK2aEmHkbhIBxLXUDNS+xgVaLeY5Z1aCICpjw73x1Wjo/n0izyIsl/hJZ6ZzX/bzE2Cc+PDAg==@lists.linux.dev X-Gm-Message-State: AOJu0YypH8ILOITK1UDyBoT0CQ03a1BBv0j8YraFbqbbsW8NoFgHAgyD 7PhoWB/R/NdTJBf50huMmodh0ldK6QW4Sefpvdjexy5L5jO6zcLX2PPLiQBApbkpeW/xRWeT71v QJg== X-Google-Smtp-Source: AGHT+IHHdPvjX46b6rya58AVmth99Sr4qyG2wQ8QULk3PUwKRfJK74c4z91IfDSthvFsL0y+9dnZ4azBoYg= X-Received: from plsb7.prod.google.com ([2002:a17:902:b607:b0:229:2f8a:d4ba]) (user=seanjc job=prod-delivery.src-stubby-dispatcher) by 2002:a17:902:d4cf:b0:220:d601:a704 with SMTP id d9443c01a7336-22be0302063mr29493945ad.18.1744300279479; Thu, 10 Apr 2025 08:51:19 -0700 (PDT) Date: Thu, 10 Apr 2025 08:51:18 -0700 In-Reply-To: Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250404211449.1443336-1-seanjc@google.com> <20250404211449.1443336-4-seanjc@google.com> Message-ID: Subject: Re: [PATCH 3/7] irqbypass: Take ownership of producer/consumer token tracking From: Sean Christopherson To: Kevin Tian Cc: "Michael S. Tsirkin" , Jason Wang , Paolo Bonzini , Alex Williamson , "kvm@vger.kernel.org" , "virtualization@lists.linux.dev" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Oliver Upton , David Matlack , Like Xu , Yong He Content-Type: text/plain; charset="us-ascii" On Thu, Apr 10, 2025, Kevin Tian wrote: > > From: Sean Christopherson > > +int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer, > > + struct eventfd_ctx *eventfd) > > { > > struct irq_bypass_consumer *tmp; > > struct irq_bypass_producer *producer; > > int ret; > > > > - if (!consumer->token || > > - !consumer->add_producer || !consumer->del_producer) > > + if (WARN_ON_ONCE(consumer->token)) > > + return -EINVAL; > > + > > + if (!consumer->add_producer || !consumer->del_producer) > > return -EINVAL; > > > > mutex_lock(&lock); > > > > list_for_each_entry(tmp, &consumers, node) { > > - if (tmp->token == consumer->token || tmp == consumer) { > > + if (tmp->token == eventfd || tmp == consumer) { > > ret = -EBUSY; > > goto out_err; > > } > > } > > the 2nd check 'tmp == consumer' is redundant. If they are equal > consumer->token is not NULL then the earlier WARN_ON will be > triggered already. Oh, nice. Good catch! That check subtly gets dropped on the conversion to xarray, so it definitely makes sense to remove it in this patch.