From owner-svn-src-head@FreeBSD.ORG Thu May 21 19:42:52 2009 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 529611065676; Thu, 21 May 2009 19:42:52 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.terabit.net.ua (mail.terabit.net.ua [195.137.202.147]) by mx1.freebsd.org (Postfix) with ESMTP id D666A8FC18; Thu, 21 May 2009 19:42:51 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from skuns.zoral.com.ua ([91.193.166.194] helo=mail.zoral.com.ua) by mail.terabit.net.ua with esmtps (TLSv1:AES256-SHA:256) (Exim 4.63 (FreeBSD)) (envelope-from ) id 1M7EAB-0009MI-DB; Thu, 21 May 2009 22:42:48 +0300 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id n4LJgiaU045029 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 21 May 2009 22:42:44 +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 (8.14.3/8.14.3) with ESMTP id n4LJgiuG061683; Thu, 21 May 2009 22:42:44 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3/Submit) id n4LJgh9f061682; Thu, 21 May 2009 22:42:43 +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: Thu, 21 May 2009 22:42:43 +0300 From: Kostik Belousov To: Attilio Rao Message-ID: <20090521194243.GW1927@deviant.kiev.zoral.com.ua> References: <3bbf2fe10905210629p46c7a204v6863aaba77354462@mail.gmail.com> <20090521.094100.70797067.imp@bsdimp.com> <4A157919.7040103@samsco.org> <200905211211.00168.jhb@freebsd.org> <20090521161535.GQ1927@deviant.kiev.zoral.com.ua> <4A157FF3.8020408@samsco.org> <20090521163846.GT1927@deviant.kiev.zoral.com.ua> <3bbf2fe10905211005m350dc4d1yed6dc1b79f1603d9@mail.gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UefMXxAhg/xpzpuf" Content-Disposition: inline In-Reply-To: <3bbf2fe10905211005m350dc4d1yed6dc1b79f1603d9@mail.gmail.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.1 at 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=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua X-Virus-Scanned: mail.terabit.net.ua 1M7EAB-0009MI-DB 621a5f5a0d089d2a0b0bd82a0fe97ae9 X-Terabit: YES Cc: Scott Long , src-committers@freebsd.org, John Baldwin , svn-src-all@freebsd.org, rwatson@freebsd.org, svn-src-head@freebsd.org, "M. Warner Losh" Subject: Re: svn commit: r192535 - head/sys/kern X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 May 2009 19:42:52 -0000 --UefMXxAhg/xpzpuf Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, May 21, 2009 at 07:05:17PM +0200, Attilio Rao wrote: > 2009/5/21 Kostik Belousov : > > On Thu, May 21, 2009 at 09:23:15AM -0700, Scott Long wrote: > >> Kostik Belousov wrote: > >> >We do have the KPI for the callers that cannot drop the locks and need > >> >to do destroy_dev, destroy_dev_sched(9). > >> > >> Good to know, I'll look at destroy_dev_sched(). =9AI'd rather not have= to > >> roll my own decoupled version. =9AAnd I understand the argument about > >> destroy_dev being a drain point for the API. =9AHowever, what about > >> create_dev()? =9AMaking that non-blocking would help a lot. > > > > create_dev() can be made non-blocking, and this is the first argument p= ro > > Attilio patch. > > > > From the quick look, all that is needed is to replace M_WAITOK with > > M_NOWAIT inside prep_cdevsw() and devfs_alloc(). Untested patch below. > > > > diff --git a/sys/fs/devfs/devfs_devs.c b/sys/fs/devfs/devfs_devs.c > > index 4041911..f470ee8 100644 > > --- a/sys/fs/devfs/devfs_devs.c > > +++ b/sys/fs/devfs/devfs_devs.c > > @@ -120,7 +120,7 @@ devfs_alloc(void) > > =9A =9A =9A =9Astruct cdev *cdev; > > =9A =9A =9A =9Astruct timespec ts; > > > > - =9A =9A =9A cdp =3D malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZE= RO | M_WAITOK); > > + =9A =9A =9A cdp =3D malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZE= RO | M_NOWAIT); > > > > =9A =9A =9A =9Acdp->cdp_dirents =3D &cdp->cdp_dirent0; > > =9A =9A =9A =9Acdp->cdp_dirent0 =3D NULL; > > diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c > > index 284f482..acdd44a 100644 > > --- a/sys/kern/kern_conf.c > > +++ b/sys/kern/kern_conf.c > > @@ -559,7 +559,7 @@ prep_cdevsw(struct cdevsw *devsw) > > =9A =9A =9A =9A =9A =9A =9A =9Areturn; > > =9A =9A =9A =9Aif (devsw->d_flags & D_NEEDGIANT) { > > =9A =9A =9A =9A =9A =9A =9A =9Adev_unlock(); > > - =9A =9A =9A =9A =9A =9A =9A dsw2 =3D malloc(sizeof *dsw2, M_DEVT, M_W= AITOK); > > + =9A =9A =9A =9A =9A =9A =9A dsw2 =3D malloc(sizeof *dsw2, M_DEVT, M_N= OWAIT); > > =9A =9A =9A =9A =9A =9A =9A =9Adev_lock(); > > =9A =9A =9A =9A} else > > =9A =9A =9A =9A =9A =9A =9A =9Adsw2 =3D NULL; >=20 > You need to check return values here if it returns NULL. >=20 > IMHO, having a non-sleepable version of destroy_dev(), create_dev() > and such would be ideal. > Ideally, we should resolve all the sleeping point and do the conversion. > I'm unable to check the code right now. Sure. Something like this. diff --git a/share/man/man9/make_dev.9 b/share/man/man9/make_dev.9 index b39ca8b..0844e64 100644 --- a/share/man/man9/make_dev.9 +++ b/share/man/man9/make_dev.9 @@ -133,6 +133,7 @@ The following values are currently accepted: .Pp .Bd -literal -offset indent -compact MAKEDEV_REF reference the created device +MAKEDEV_NOWAIT do not sleep, may return NULL .Ed .Pp The diff --git a/sys/fs/devfs/devfs_devs.c b/sys/fs/devfs/devfs_devs.c index 4041911..79f7893 100644 --- a/sys/fs/devfs/devfs_devs.c +++ b/sys/fs/devfs/devfs_devs.c @@ -114,17 +114,21 @@ SYSCTL_INT(_debug_sizeof, OID_AUTO, cdev_priv, CTLFLA= G_RD, 0, sizeof(struct cdev_priv), "sizeof(struct cdev_priv)"); =20 struct cdev * -devfs_alloc(void) +devfs_alloc(int flags) { struct cdev_priv *cdp; struct cdev *cdev; struct timespec ts; =20 - cdp =3D malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO | M_WAITOK); + cdp =3D malloc(sizeof *cdp, M_CDEVP, M_USE_RESERVE | M_ZERO | + ((flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK)); + if (cdp =3D=3D NULL) + return (NULL); =20 cdp->cdp_dirents =3D &cdp->cdp_dirent0; cdp->cdp_dirent0 =3D NULL; cdp->cdp_maxdirent =3D 0; + cdp->cdp_inode =3D 0; =20 cdev =3D &cdp->cdp_c; =20 @@ -132,6 +136,7 @@ devfs_alloc(void) LIST_INIT(&cdev->si_children); vfs_timestamp(&ts); cdev->si_atime =3D cdev->si_mtime =3D cdev->si_ctime =3D ts; + cdev->si_cred =3D NULL; =20 return (cdev); } diff --git a/sys/fs/devfs/devfs_int.h b/sys/fs/devfs/devfs_int.h index 5a61dd4..f5612e1 100644 --- a/sys/fs/devfs/devfs_int.h +++ b/sys/fs/devfs/devfs_int.h @@ -70,7 +70,7 @@ struct cdev_priv { =20 #define cdev2priv(c) member2struct(cdev_priv, cdp_c, c) =20 -struct cdev *devfs_alloc(void); +struct cdev *devfs_alloc(int); void devfs_free(struct cdev *); void devfs_create(struct cdev *dev); void devfs_destroy(struct cdev *dev); diff --git a/sys/kern/kern_conf.c b/sys/kern/kern_conf.c index 284f482..082f5d3 100644 --- a/sys/kern/kern_conf.c +++ b/sys/kern/kern_conf.c @@ -482,7 +482,7 @@ giant_mmap(struct cdev *dev, vm_offset_t offset, vm_pad= dr_t *paddr, int nprot) =20 =20 static void -notify(struct cdev *dev, const char *ev) +notify(struct cdev *dev, const char *ev, int flags) { static const char prefix[] =3D "cdev=3D"; char *data; @@ -491,7 +491,8 @@ notify(struct cdev *dev, const char *ev) if (cold) return; namelen =3D strlen(dev->si_name); - data =3D malloc(namelen + sizeof(prefix), M_TEMP, M_NOWAIT); + data =3D malloc(namelen + sizeof(prefix), M_TEMP, + (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK); if (data =3D=3D NULL) return; memcpy(data, prefix, sizeof(prefix) - 1); @@ -501,17 +502,17 @@ notify(struct cdev *dev, const char *ev) } =20 static void -notify_create(struct cdev *dev) +notify_create(struct cdev *dev, int flags) { =20 - notify(dev, "CREATE"); + notify(dev, "CREATE", flags); } =20 static void notify_destroy(struct cdev *dev) { =20 - notify(dev, "DESTROY"); + notify(dev, "DESTROY", 0); } =20 static struct cdev * @@ -549,24 +550,27 @@ fini_cdevsw(struct cdevsw *devsw) devsw->d_flags &=3D ~D_INIT; } =20 -static void -prep_cdevsw(struct cdevsw *devsw) +static int +prep_cdevsw(struct cdevsw *devsw, int flags) { struct cdevsw *dsw2; =20 mtx_assert(&devmtx, MA_OWNED); if (devsw->d_flags & D_INIT) - return; + return (1); if (devsw->d_flags & D_NEEDGIANT) { dev_unlock(); - dsw2 =3D malloc(sizeof *dsw2, M_DEVT, M_WAITOK); + dsw2 =3D malloc(sizeof *dsw2, M_DEVT, + (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK); dev_lock(); + if (dsw2 =3D=3D NULL && !(devsw->d_flags & D_INIT)) + return (0); } else dsw2 =3D NULL; if (devsw->d_flags & D_INIT) { if (dsw2 !=3D NULL) cdevsw_free_devlocked(dsw2); - return; + return (1); } =20 if (devsw->d_version !=3D D_VERSION_01) { @@ -622,6 +626,7 @@ prep_cdevsw(struct cdevsw *devsw) =20 if (dsw2 !=3D NULL) cdevsw_free_devlocked(dsw2); + return (1); } =20 struct cdev * @@ -632,9 +637,15 @@ make_dev_credv(int flags, struct cdevsw *devsw, int un= it, struct cdev *dev; int i; =20 - dev =3D devfs_alloc(); + dev =3D devfs_alloc(flags); + if (dev =3D=3D NULL) + return (NULL); dev_lock(); - prep_cdevsw(devsw); + if (!prep_cdevsw(devsw, flags)) { + dev_unlock(); + devfs_free(dev); + return (NULL); + } dev =3D newdev(devsw, unit, dev); if (flags & MAKEDEV_REF) dev_refl(dev); @@ -661,8 +672,6 @@ make_dev_credv(int flags, struct cdevsw *devsw, int uni= t, dev->si_flags |=3D SI_NAMED; if (cr !=3D NULL) dev->si_cred =3D crhold(cr); - else - dev->si_cred =3D NULL; dev->si_uid =3D uid; dev->si_gid =3D gid; dev->si_mode =3D mode; @@ -671,7 +680,7 @@ make_dev_credv(int flags, struct cdevsw *devsw, int uni= t, clean_unrhdrl(devfs_inos); dev_unlock_and_free(); =20 - notify_create(dev); + notify_create(dev, flags); =20 return (dev); } @@ -746,7 +755,7 @@ make_dev_alias(struct cdev *pdev, const char *fmt, ...) int i; =20 KASSERT(pdev !=3D NULL, ("NULL pdev")); - dev =3D devfs_alloc(); + dev =3D devfs_alloc(0); dev_lock(); dev->si_flags |=3D SI_ALIAS; dev->si_flags |=3D SI_NAMED; @@ -763,7 +772,7 @@ make_dev_alias(struct cdev *pdev, const char *fmt, ...) clean_unrhdrl(devfs_inos); dev_unlock(); =20 - notify_create(dev); + notify_create(dev, 0); =20 return (dev); } @@ -947,9 +956,9 @@ clone_create(struct clonedevs **cdp, struct cdevsw *csw= , int *up, struct cdev ** * the end of the list. */ unit =3D *up; - ndev =3D devfs_alloc(); + ndev =3D devfs_alloc(0); dev_lock(); - prep_cdevsw(csw); + prep_cdevsw(csw, 0); low =3D extra; de =3D dl =3D NULL; cd =3D *cdp; diff --git a/sys/sys/conf.h b/sys/sys/conf.h index 05c4bb5..7b65862 100644 --- a/sys/sys/conf.h +++ b/sys/sys/conf.h @@ -263,6 +263,7 @@ struct cdev *make_dev_cred(struct cdevsw *_devsw, int _= unit, const char *_fmt, ...) __printflike(7, 8); #define MAKEDEV_REF 0x1 #define MAKEDEV_WHTOUT 0x2 +#define MAKEDEV_NOWAIT 0x4 struct cdev *make_dev_credf(int _flags, struct cdevsw *_devsw, int _unit, struct ucred *_cr, uid_t _uid, gid_t _gid, int _mode, --UefMXxAhg/xpzpuf Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkoVrrMACgkQC3+MBN1Mb4hbtgCfSuOC9WSmOblI7zgHXjPpuu0n WRUAnjLxpNr79a+EgvMQlMrzXWlTA4GQ =HA2n -----END PGP SIGNATURE----- --UefMXxAhg/xpzpuf--