Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760844AbcDFAac (ORCPT ); Tue, 5 Apr 2016 20:30:32 -0400 Received: from mail-pa0-f67.google.com ([209.85.220.67]:35023 "EHLO mail-pa0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760815AbcDFAaa (ORCPT ); Tue, 5 Apr 2016 20:30:30 -0400 Date: Tue, 5 Apr 2016 16:30:25 -0800 From: Kent Overstreet To: Ming Lei Cc: Jens Axboe , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, Christoph Hellwig , Eric Wheeler , Sebastian Roesner , "4.2+" , Shaohua Li Subject: Re: [PATCH] block: make sure big bio is splitted into at most 256 bvecs Message-ID: <20160406003025.GC31161@kmo-pixel> References: <1459878246-9249-1-git-send-email-ming.lei@canonical.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1459878246-9249-1-git-send-email-ming.lei@canonical.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 477 Lines: 10 On Wed, Apr 06, 2016 at 01:44:06AM +0800, Ming Lei wrote: > After arbitrary bio size is supported, the incoming bio may > be very big. We have to split the bio into small bios so that > each holds at most BIO_MAX_PAGES bvecs for safety reason, such > as bio_clone(). > > This patch fixes the following kernel crash: Ming, let's not do it this way; drivers that don't clone biovecs are the norm - instead, md has its own queue limits that it ought to be setting up correctly.