From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <1c57005277ac723ebb670a1dc847a205f0529d53.camel@opteya.com> From: Yann Droneaud To: David Howells , linux-api@vger.kernel.org, linux-kbuild@vger.kernel.org Cc: Jan Harkes , coda@cs.cmu.edu, codalist@coda.cs.cmu.edu, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 05 Sep 2018 19:12:37 +0200 In-Reply-To: <153616291029.23468.16421004714304578585.stgit@warthog.procyon.org.uk> References: <153616286704.23468.584491117180383924.stgit@warthog.procyon.org.uk> <153616291029.23468.16421004714304578585.stgit@warthog.procyon.org.uk> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH 05/11] UAPI: coda: Don't use internal kernel structs in UAPI Sender: linux-kernel-owner@vger.kernel.org List-ID: Le mercredi 05 septembre 2018 à 16:55 +0100, David Howells a écrit : > The size and layout of internal kernel structures may not be relied > upon outside of the kernel and may even change in a containerised > environment if a container image is frozen and shifted to another > machine. > > Excise these from Coda's upc_req struct. > > Signed-off-by: David Howells > cc: Jan Harkes > cc: coda@cs.cmu.edu > cc: codalist@coda.cs.cmu.edu > cc: linux-fsdevel@vger.kernel.org > --- > > include/uapi/linux/coda_psdev.h | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/include/uapi/linux/coda_psdev.h b/include/uapi/linux/coda_psdev.h > index aa6623efd2dd..9c3acde393cd 100644 > --- a/include/uapi/linux/coda_psdev.h > +++ b/include/uapi/linux/coda_psdev.h > @@ -10,14 +10,18 @@ > > /* messages between coda filesystem in kernel and Venus */ > struct upc_req { > +#ifdef __KERNEL__ > struct list_head uc_chain; > +#endif > caddr_t uc_data; > u_short uc_flags; > u_short uc_inSize; /* Size is at most 5000 bytes */ > u_short uc_outSize; > u_short uc_opcode; /* copied from data to save lookup */ > int uc_unique; > +#ifdef __KERNEL__ > wait_queue_head_t uc_sleep; /* process' wait queue */ > +#endif > }; > This structure should not have been exposed to userspace in the first place: it's unusable by userspace as it is. It was incorrect to have it outside of #ifdef __KERNEL__ before commit 607ca46e97a1b ... ... and it's not exchanged between kernel and userspace, see coda_psdev_write(): struct upc_req *req = NULL; ... if (copy_from_user(req->uc_data, buf, nbytes)) { req->uc_flags |= CODA_REQ_ABORT; wake_up(&req->uc_sleep); retval = -EFAULT; goto out; } Only data, a caddr_t, is read from userspace. So the structure can be moved back to . > #define CODA_REQ_ASYNC 0x1 > All CODA_REQ_* defines internals to kernel side and not exchanged with userspace. Please move them back to Regards. -- Yann Droneaud OPTEYA