From a29e977f9cadcec93df669556048c22f50058f4a Mon Sep 17 00:00:00 2001 From: deraadt Date: Thu, 14 Dec 1995 06:20:26 +0000 Subject: [PATCH] from netbsd: Bring in several changes from the ccd: * Be a bit better with prototypes * Use struct dkdevice in vnd_softc. * Prevent the unit from being unconfigured while open. * Implement a simple locking mechanism and use it for sanity's sake. Still needs more work; needs to support disklabels and the like. --- sys/dev/vnd.c | 210 +++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 190 insertions(+), 20 deletions(-) diff --git a/sys/dev/vnd.c b/sys/dev/vnd.c index 1c8e5109bbb..52b32f5eca8 100644 --- a/sys/dev/vnd.c +++ b/sys/dev/vnd.c @@ -1,4 +1,4 @@ -/* $NetBSD: vnd.c,v 1.21 1995/10/05 06:20:57 mycroft Exp $ */ +/* $NetBSD: vnd.c,v 1.22 1995/11/06 20:28:09 thorpej Exp $ */ /* * Copyright (c) 1988 University of Utah. @@ -60,8 +60,6 @@ * * NOTE 3: Doesn't interact with leases, should it? */ -#include "vnd.h" -#if NVND > 0 #include #include @@ -73,6 +71,10 @@ #include #include #include +#include +#include +#include +#include #include #include #include @@ -111,25 +113,37 @@ struct vnd_softc { struct ucred *sc_cred; /* credentials */ int sc_maxactive; /* max # of active requests */ struct buf sc_tab; /* transfer queue */ + struct dkdevice sc_dkdev; /* generic disk device info */ }; /* sc_flags */ #define VNF_ALIVE 0x01 #define VNF_INITED 0x02 +#define VNF_WANTED 0x40 +#define VNF_LOCKED 0x80 -#if 0 /* if you need static allocation */ -struct vnd_softc vn_softc[NVND]; -int numvnd = NVND; -#else struct vnd_softc *vnd_softc; -int numvnd; -#endif +int numvnd = 0; + +/* {b,c}devsw[] function prototypes */ +dev_type_open(vndopen); +dev_type_close(vndclose); +dev_type_strategy(vndstrategy); +dev_type_ioctl(vndioctl); +dev_type_read(vndread); +dev_type_write(vndwrite); + +/* called by main() at boot time */ +void vndattach __P((int)); void vndclear __P((struct vnd_softc *)); void vndstart __P((struct vnd_softc *)); int vndsetcred __P((struct vnd_softc *, struct ucred *)); void vndthrottle __P((struct vnd_softc *, struct vnode *)); +static int vndlock __P((struct vnd_softc *)); +static void vndunlock __P((struct vnd_softc *)); + void vndattach(num) int num; @@ -157,14 +171,42 @@ vndopen(dev, flags, mode, p) struct proc *p; { int unit = vndunit(dev); + struct vnd_softc *sc; + int error = 0, part, pmask; + + /* + * XXX Should support disklabels. + */ #ifdef DEBUG if (vnddebug & VDB_FOLLOW) printf("vndopen(%x, %x, %x, %x)\n", dev, flags, mode, p); #endif if (unit >= numvnd) - return(ENXIO); - return(0); + return (ENXIO); + sc = &vnd_softc[unit]; + + if (error = vndlock(sc)) + return (error); + + part = DISKPART(dev); + pmask = (1 << part); + + /* Prevent our unit from being unconfigured while open. */ + switch (mode) { + case S_IFCHR: + sc->sc_dkdev.dk_copenmask |= pmask; + break; + + case S_IFBLK: + sc->sc_dkdev.dk_bopenmask |= pmask; + break; + } + sc->sc_dkdev.dk_openmask = + sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask; + + vndunlock(sc); + return (0); } int @@ -173,11 +215,39 @@ vndclose(dev, flags, mode, p) int flags, mode; struct proc *p; { + int unit = vndunit(dev); + struct vnd_softc *sc; + int error = 0, part; + #ifdef DEBUG if (vnddebug & VDB_FOLLOW) printf("vndclose(%x, %x, %x, %x)\n", dev, flags, mode, p); #endif - return 0; + + if (unit >= numvnd) + return (ENXIO); + sc = &vnd_softc[unit]; + + if (error = vndlock(sc)) + return (error); + + part = DISKPART(dev); + + /* ...that much closer to allowing unconfiguration... */ + switch (mode) { + case S_IFCHR: + sc->sc_dkdev.dk_copenmask &= ~(1 << part); + break; + + case S_IFBLK: + sc->sc_dkdev.dk_bopenmask &= ~(1 << part); + break; + } + sc->sc_dkdev.dk_openmask = + sc->sc_dkdev.dk_copenmask | sc->sc_dkdev.dk_bopenmask; + + vndunlock(sc); + return (0); } /* @@ -375,29 +445,53 @@ vndiodone(vbp) splx(s); } +/* ARGSUSED */ int -vndread(dev, uio) +vndread(dev, uio, flags) dev_t dev; struct uio *uio; + int flags; { + int unit = vndunit(dev); + struct vnd_softc *sc; #ifdef DEBUG if (vnddebug & VDB_FOLLOW) printf("vndread(%x, %x)\n", dev, uio); #endif + + if (unit >= numvnd) + return (ENXIO); + sc = &vnd_softc[unit]; + + if ((sc->sc_flags & VNF_INITED) == 0) + return (ENXIO); + return (physio(vndstrategy, NULL, dev, B_READ, minphys, uio)); } +/* ARGSUSED */ int -vndwrite(dev, uio) +vndwrite(dev, uio, flags) dev_t dev; struct uio *uio; + int flags; { + int unit = vndunit(dev); + struct vnd_softc *sc; #ifdef DEBUG if (vnddebug & VDB_FOLLOW) printf("vndwrite(%x, %x)\n", dev, uio); #endif + + if (unit >= numvnd) + return (ENXIO); + sc = &vnd_softc[unit]; + + if ((sc->sc_flags & VNF_INITED) == 0) + return (ENXIO); + return (physio(vndstrategy, NULL, dev, B_WRITE, minphys, uio)); } @@ -415,7 +509,7 @@ vndioctl(dev, cmd, data, flag, p) struct vnd_ioctl *vio; struct vattr vattr; struct nameidata nd; - int error; + int error, part, pmask, s; #ifdef DEBUG if (vnddebug & VDB_FOLLOW) @@ -434,7 +528,11 @@ vndioctl(dev, cmd, data, flag, p) case VNDIOCSET: if (vnd->sc_flags & VNF_INITED) - return(EBUSY); + return (EBUSY); + + if (error = vndlock(vnd)) + return (error); + /* * Always open for read and write. * This is probably bogus, but it lets vn_open() @@ -442,11 +540,14 @@ vndioctl(dev, cmd, data, flag, p) * have to worry about them. */ NDINIT(&nd, LOOKUP, FOLLOW, UIO_USERSPACE, vio->vnd_file, p); - if (error = vn_open(&nd, FREAD|FWRITE, 0)) + if (error = vn_open(&nd, FREAD|FWRITE, 0)) { + vndunlock(vnd); return(error); + } if (error = VOP_GETATTR(nd.ni_vp, &vattr, p->p_ucred, p)) { VOP_UNLOCK(nd.ni_vp); (void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p); + vndunlock(vnd); return(error); } VOP_UNLOCK(nd.ni_vp); @@ -454,6 +555,7 @@ vndioctl(dev, cmd, data, flag, p) vnd->sc_size = btodb(vattr.va_size); /* note truncation */ if (error = vndsetcred(vnd, p->p_ucred)) { (void) vn_close(nd.ni_vp, FREAD|FWRITE, p->p_ucred, p); + vndunlock(vnd); return(error); } vndthrottle(vnd, vnd->sc_vp); @@ -464,22 +566,55 @@ vndioctl(dev, cmd, data, flag, p) printf("vndioctl: SET vp %x size %x\n", vnd->sc_vp, vnd->sc_size); #endif + + vndunlock(vnd); + break; case VNDIOCCLR: if ((vnd->sc_flags & VNF_INITED) == 0) - return(ENXIO); + return (ENXIO); + + if (error = vndlock(vnd)) + return (error); + + /* + * Don't unconfigure if any other partitions are open + * or if both the character and block flavors of this + * partition are open. + */ + part = DISKPART(dev); + pmask = (1 << part); + if ((vnd->sc_dkdev.dk_openmask & ~pmask) || + ((vnd->sc_dkdev.dk_bopenmask & pmask) && + (vnd->sc_dkdev.dk_copenmask & pmask))) { + vndunlock(vnd); + return (EBUSY); + } + vndclear(vnd); #ifdef DEBUG if (vnddebug & VDB_INIT) printf("vndioctl: CLRed\n"); #endif + + /* This must be atomic. */ + s = splhigh(); + vndunlock(vnd); + bzero(vnd, sizeof(struct vnd_softc)); + splx(s); + break; + /* + * XXX Should support disklabels. + */ + default: return(ENOTTY); } - return(0); + + return (0); } /* @@ -593,4 +728,39 @@ vnddump(dev, blkno, va, size) /* Not implemented. */ return ENXIO; } -#endif + +/* + * Wait interruptibly for an exclusive lock. + * + * XXX + * Several drivers do this; it should be abstracted and made MP-safe. + */ +static int +vndlock(sc) + struct vnd_softc *sc; +{ + int error; + + while ((sc->sc_flags & VNF_LOCKED) != 0) { + sc->sc_flags |= VNF_WANTED; + if ((error = tsleep(sc, PRIBIO | PCATCH, "vndlck", 0)) != 0) + return (error); + } + sc->sc_flags |= VNF_LOCKED; + return (0); +} + +/* + * Unlock and wake up any waiters. + */ +static void +vndunlock(sc) + struct vnd_softc *sc; +{ + + sc->sc_flags &= ~VNF_LOCKED; + if ((sc->sc_flags & VNF_WANTED) != 0) { + sc->sc_flags &= ~VNF_WANTED; + wakeup(sc); + } +} -- 2.20.1