From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Theodore Y. Ts'o" Subject: Re: [PATCH 0/3] SG_IO command filtering via sysfs Date: Fri, 16 Nov 2018 12:35:51 -0500 Message-ID: <20181116173551.GG20617@thunk.org> References: <1541867733-7836-1-git-send-email-pbonzini@redhat.com> <20181110190521.GA2627@thunk.org> <566bc821-f12a-f7c1-e7c7-99092807ee27@redhat.com> <20181111141426.GA7377@thunk.org> <98fe5cf7-722a-37d6-156d-842e8812e430@redhat.com> <1542328654.100259.18.camel@acm.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Paolo Bonzini Cc: Bart Van Assche , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Hannes Reinecke , "Martin K. Petersen" , James Bottomley , Christoph Hellwig List-Id: linux-scsi@vger.kernel.org On Fri, Nov 16, 2018 at 08:01:29AM +0100, Paolo Bonzini wrote: > On 16/11/18 01:37, Bart Van Assche wrote: > > All user space interfaces in the Linux kernel for storage that I'm familiar > > with not only allow configuration of parameters but also make it easy to > > query which parameters have been configured. The existing sysfs and configfs > > interfaces demonstrate this. Using BPF to configure SG/IO access has a > > significant disadvantage, namely that it is very hard to figure out what has > > been configured. Figuring out what has been configured namely requires > > disassembling BPF. I'm not sure anyone will be enthusiast about this. > > Well, that's a problem with BPF in general. With great power comes > great obscurability. You can also make the same complaint about kernel modules; that it's impossible to figure exactly what a kernel modules does without disassembling them. However, you can a one-line description of what it does using modinfo: % modinfo async_pq filename: /lib/modules/4.19.0-00022-g831156939ae8/kernel/crypto/async_tx/async_pq.ko license: GPL description: asynchronous raid6 syndrome generation/validation srcversion: 529102C736C4FED181C15A8 depends: raid6_pq,async_tx,async_xor retpoline: Y intree: Y name: async_pq vermagic: 4.19.0-00022-g831156939ae8 SMP mod_unload modversions - Ted