From owner-freebsd-arch@FreeBSD.ORG Sun May 11 11:58:24 2008 Return-Path: Delivered-To: arch@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 781F9106566C for ; Sun, 11 May 2008 11:58:24 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from relay03.kiev.sovam.com (relay03.kiev.sovam.com [62.64.120.201]) by mx1.freebsd.org (Postfix) with ESMTP id 147BB8FC16 for ; Sun, 11 May 2008 11:58:24 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from [212.82.216.226] (helo=skuns.kiev.zoral.com.ua) by relay03.kiev.sovam.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.67) (envelope-from ) id 1JvAC6-00024j-5d for arch@freebsd.org; Sun, 11 May 2008 14:58:22 +0300 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by skuns.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m4BBwIM3067849 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 11 May 2008 14:58:19 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m4BBwGno039119; Sun, 11 May 2008 14:58:16 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2/Submit) id m4BBwFeB039118; Sun, 11 May 2008 14:58:15 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Sun, 11 May 2008 14:58:15 +0300 From: Kostik Belousov To: Jeff Roberson Message-ID: <20080511115815.GW18958@deviant.kiev.zoral.com.ua> References: <20080504171002.GN18958@deviant.kiev.zoral.com.ua> <20080510214812.Y954@desktop> <20080511115030.GV18958@deviant.kiev.zoral.com.ua> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="/L9TK8VZ3nvnToYi" Content-Disposition: inline In-Reply-To: <20080511115030.GV18958@deviant.kiev.zoral.com.ua> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: ClamAV version 0.91.2, clamav-milter version 0.91.2 on skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.4 X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on skuns.kiev.zoral.com.ua X-Scanner-Signature: 021e97fb5facab6d3ae496d7b6c27559 X-DrWeb-checked: yes X-SpamTest-Envelope-From: kostikbel@gmail.com X-SpamTest-Group-ID: 00000000 X-SpamTest-Header: Not Detected X-SpamTest-Info: Profiles 2798 [May 08 2008] X-SpamTest-Info: helo_type=3 X-SpamTest-Method: none X-SpamTest-Rate: 0 X-SpamTest-Status: Not detected X-SpamTest-Status-Extended: not_detected X-SpamTest-Version: SMTP-Filter Version 3.0.0 [0278], KAS30/Release Cc: arch@freebsd.org Subject: Re: Per-open file private data for the cdevs X-BeenThere: freebsd-arch@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussion related to FreeBSD architecture List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 May 2008 11:58:24 -0000 --/L9TK8VZ3nvnToYi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, May 11, 2008 at 02:50:30PM +0300, Kostik Belousov wrote: > On Sat, May 10, 2008 at 09:53:12PM -1000, Jeff Roberson wrote: > > On Sun, 4 May 2008, Kostik Belousov wrote: > >=20 > > >Since the review for the clone-at-open patch (fdclone) posted some tim= e ago > > >mostly says that it would be better to implement per-file private data > > >instead, I produced the patch along this line, > > > > > >The patch does not change the cdevsw ABI, instead, three new functions > > >nt devfs_get_cdevpriv(void **datap); > > >int devfs_set_cdevpriv(void *priv, cdevpriv_dtr_t dtr); > > >void devfs_clear_cdevpriv(void); > > >are provided for manipulation of the per-file private data. > > > > > >devfs_set_cdevpriv assigns the priv as private data for the file descr= iptor > > >which is used to initiate currently performed driver operation. dtr > > >is the function that will be called when either the last refernce to > > >the file goes away or devfs_clear_cdevpriv is called. > > > > > >devfs_get_cdevpriv is the obvious accessor. > > > > > >devfs_clear_cdevpriv allows to clear the private data for the still > > >open file. > > > > > >The synchronization of the cdev data and file private data is left > > >to the driver code, I did not found any generic helper mechanism that > > >could be useful there. > > > > > >Patch: > > >http://people.freebsd.org/~kib/misc/fdpriv.1.patch > > > > > >Dumb driver that shows the basic usage of the proposed KPI: > > >http://people.freebsd.org/~kib/misc/fpclone.c > > > > > >Previous version of the patch was tested by Peter Holm. > > > > >=20 > > Hi Kostik, > >=20 > > Are these per-instances structures intended to be used by anything othe= r=20 > > than devices? If not can we make them a union with the DTYPE_VNODE=20 > > fields to save space? > >=20 > > Thanks, > > Jeff >=20 > The current version of the patch is at > http://people.freebsd.org/~kib/misc/fdpriv.3.patch >=20 > Per insistence of John Baldwin and request of Eric Anholt, the destructors > are called now when either file is last closed, or the device is destroye= d. > This versions adds only one pointer to the struct file. >=20 > Jeff, would you, please, explicitely specify what field you propose to > union with the f_cdevpriv ?=20 Of course, I forgot to answer the question. Yes, the KPI is supposed to be used by the drivers only. Please, note that device open files have DTYPE_VNODE. --/L9TK8VZ3nvnToYi Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkgm31cACgkQC3+MBN1Mb4hZFgCgg3EoqJOLVqCdzU20iDUZUbCl MfcAoJsv6jMtdtAt/wm6tFLviWIHRveR =qE5J -----END PGP SIGNATURE----- --/L9TK8VZ3nvnToYi--