From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 2C6963B3C05 for ; Wed, 26 Aug 2026 19:49:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787773762; cv=none; b=OUmN3AuqgxOR0Ku9GKxFD57O7KbHSfJELjJ2O/HL9IH/uzg38S9y07G3mQ+djfede2Q86mzqi0pzG9C7Jl9f09udQLEqCPOtNoDhaEv62Cu4Chb1kru0kKW/oqebaKZLk9zN7bwQ2bqwGD0VSmRHZfKy18yPLztRBRf8Tdu1B9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787773762; c=relaxed/simple; bh=y9g2ualI/bK6M+PISVPgksBz/q7GbK0yHm3ggAbxYGc=; h=From:In-Reply-To:References:To:Cc:Subject:MIME-Version: Content-Type:Date:Message-ID; b=fAFjCZD045HZoPQdepnhotiOoeY8EJTvEtPfAkHS433byVmQno0dcySdzTXENSfDA+ODzoWSwCmsx02abuWM9OUaImj6W6K8aL51ROyO6GELVGowKqIdFBTztJU9F7LPJDwDU/n7De2OJG/Hsjvsz5lnvO4CnBHiabCuKhY2AaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=avUJyrpM; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="avUJyrpM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787773751; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=tuNSEaT3GKGdOWYWz+Vtzv8wtmbE7GwqDneMzbaR/Ys=; b=avUJyrpMZ+HYcv+v7DiW6C9LvEbRJBR1LnkT/71/WiUPQF2P/7MzIUl6X373oCyZGJvYcn 91Zrqpi6tHTn9k59jWg3WTBSJvqX4FsPkv/tR7Mo3mTr/K/ybNMfck4zMHItKYpwmoUfEy XRCnSG5RvOR1kdLhSHXewl/G4K3ZyZk= Received: from mx-prod-mc-05.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-518-NVaS2IIWMbGp8zxC6NffEg-1; Wed, 26 Aug 2026 15:49:08 -0400 X-MC-Unique: NVaS2IIWMbGp8zxC6NffEg-1 X-Mimecast-MFC-AGG-ID: NVaS2IIWMbGp8zxC6NffEg_1787773745 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1840B1954B13; Wed, 26 Aug 2026 19:49:05 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.22.88.47]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id E75D11955F43; Wed, 26 Aug 2026 19:49:01 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <1819786.1787768317@warthog.procyon.org.uk> To: Keith Busch Cc: dhowells@redhat.com, Jens Axboe , Hannes Reinecke , Christoph Hellwig , Alexander Viro , Paulo Alcantara , netfs@lists.linux.dev, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] block: Fix start and length check added to iov_iter_extract_bvecs() Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1864927.1787773740.1@warthog.procyon.org.uk> Date: Wed, 26 Aug 2026 20:49:00 +0100 Message-ID: <1864928.1787773740@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Keith Busch wrote: > iov_iter_alignment loops over all the vectors when we only need to > examine the current one here. Actually, I don't think that's true. iov_iter_extract_pages() is allowed to pull from multiple bio_vecs in an ITER_BVEC, for example - and if, say, the page in the second bio_vec is contiguous with the first, then iov_iter_extract_bvecs() will use it - so you still need to check bv_len on it. David