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 791BC1E5201 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=1744300282; cv=none; b=j8fUEywFOIbgCg5ZHaCxBUDR/T/RxbQO9GFHr8XXHyFB7mugaYRwUjvYJgSrP9hQkgwT7rg6FPAMx1tyKarEpknivigwNEh3LzURJUHgBtLSxV5W/f7Ld5i169IU3+emgOWBYQbvAD9FVJKgi6zzDohDULOvCMqIQ9cdR3frvqY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744300282; c=relaxed/simple; bh=I1HL4EhttE881MicAtF32b66FddNBn0rz1b+bJ5vSpI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=ihXIq+mnf5XHXpsuohSku5tUK8KqUPlzpJcTdObEyBKbzJPaLMQG1rRS2xQxsnlVeRrclLjTHSNLB50pcwny56AjXwGsXZPXPF19xiWnDihbxuZj8Xt9xVk+iy7dslru2S5Hppv8vwaNI63oIXzC6mF7e59+MEGXz5fQs26IJsE= 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=IkZFaSgD; 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="IkZFaSgD" Received: by mail-pl1-f201.google.com with SMTP id d9443c01a7336-22403329f9eso8455005ad.3 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=vger.kernel.org; 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=IkZFaSgDMxVLDJYiztqhLWeJ9BKaBmCbT7F4CFXTzXGHk78dhVZw31jouCnNDop6qG LyvJ2AGGW9B/NjGJES68OuKAKaLBwFvD2KGUWdvUlsG1f0aD8K6C+rGbK5ysE6vJ1dDv +K+JpZcy29v0dUf1sfGwTYaAYrUFfG7GrYAzIQi7CH+jkldW1WG3aBanwL1UNOUAXBRV bHMPWtECNA0qzJQhzQzy4ceyGFHvF2uUxZwwYnkpxqCNMe6h/tq8OFE5STxYBiSEa0NU lfHoRRzZvrm0R3beELu0HF0TwdJm5QdJx8sDTJg7rPPsfd5OuFieaYBGI8NvdpPXr494 9s4g== 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=O5EUaq0xP51CYQOno/603tw8Nf9UbA9FLRx1RUqJiolwLHJoVtaS3dANKVijeeGP/s Z5DIVg0F1Y7wYgnuiEa69eT90gEPn/mGAy8jYhCsz2BfJn45+wpe/tHcJkOuqhh+Znba eSCQio6g6FZuKtQ6UTCFsdYNqLLgiV26hCT2Quio5SWKEvTOwBtVs4gW1mJPXz9LQjq3 y5D62Mwf+mWczE1vXnUmI8Ur5a6AHsWmDkjRuK2lHbRk0RxOtdjOy9qQ+nV8+ulVPuLG zwq65Nkv2R/GRwNHva0OM7+dg4uCtqQvqAQAXsqPY9fkdvPlyivkqW+IIWRuZlbcQeQK U/LA== X-Forwarded-Encrypted: i=1; AJvYcCUe/wva8iRfOCcZ2SqaO9mTkE2mOhN72WUveEUkJwSXUZlErjZT0CTcGJznkgowmU7WwkVw1h8vGcJ8i84=@vger.kernel.org X-Gm-Message-State: AOJu0Yz8w2RcrGJSy7JBzWetb5PggyBxsrcsad0e0WwPNJQHIcQevWPj BGuoJ3D2vn3PJADe/G/GDa9FrfqBvtV6VsaIiPg2sOSdGVB1jF8s79Mo5EWC2VJ3LUEKj0lMFoK CMw== 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: linux-kernel@vger.kernel.org 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.