diff options
Diffstat (limited to 'sys/kern/subr_autoconf.c')
| -rw-r--r-- | sys/kern/subr_autoconf.c | 39 |
1 files changed, 36 insertions, 3 deletions
diff --git a/sys/kern/subr_autoconf.c b/sys/kern/subr_autoconf.c index 8f641ee706d..57324b0bfb5 100644 --- a/sys/kern/subr_autoconf.c +++ b/sys/kern/subr_autoconf.c @@ -1,4 +1,4 @@ -/* $OpenBSD: subr_autoconf.c,v 1.64 2011/06/01 03:25:01 matthew Exp $ */ +/* $OpenBSD: subr_autoconf.c,v 1.65 2011/06/20 17:05:46 deraadt Exp $ */ /* $NetBSD: subr_autoconf.c,v 1.21 1996/04/04 06:06:18 cgd Exp $ */ /* @@ -51,6 +51,7 @@ #include <sys/systm.h> #include <sys/queue.h> #include <sys/proc.h> +#include <sys/mutex.h> #include "hotplug.h" @@ -100,6 +101,14 @@ struct devicelist alldevs; /* list of all devices */ __volatile int config_pending; /* semaphore for mountroot */ +struct mutex autoconf_attdet_mtx = MUTEX_INITIALIZER(IPL_HIGH); +/* + * If > 0, devices are being attached and any thread which tries to + * detach will sleep; if < 0 devices are being detached and any + * thread which tries to attach will sleep. + */ +int autoconf_attdet; + /* * Initialize autoconfiguration data structures. This occurs before console * initialization as that might require use of this subsystem. Furthermore @@ -339,6 +348,13 @@ config_attach(struct device *parent, void *match, void *aux, cfprint_t print) struct cfattach *ca; struct cftable *t; + mtx_enter(&autoconf_attdet_mtx); + while (autoconf_attdet < 0) + msleep(&autoconf_attdet, &autoconf_attdet_mtx, + PWAIT, "autoconf", 0); + autoconf_attdet++; + mtx_leave(&autoconf_attdet_mtx); + if (parent && parent->dv_cfdata->cf_driver->cd_indirect) { dev = match; cf = dev->dv_cfdata; @@ -398,6 +414,11 @@ config_attach(struct device *parent, void *match, void *aux, cfprint_t print) if (!cold) hotplug_device_attach(cd->cd_class, dev->dv_xname); #endif + + mtx_enter(&autoconf_attdet_mtx); + if (--autoconf_attdet == 0) + wakeup(&autoconf_attdet); + mtx_leave(&autoconf_attdet_mtx); return (dev); } @@ -495,6 +516,13 @@ config_detach(struct device *dev, int flags) char devname[16]; #endif + mtx_enter(&autoconf_attdet_mtx); + while (autoconf_attdet > 0) + msleep(&autoconf_attdet, &autoconf_attdet_mtx, + PWAIT, "autoconf", 0); + autoconf_attdet--; + mtx_leave(&autoconf_attdet_mtx); + #if NHOTPLUG > 0 strlcpy(devname, dev->dv_xname, sizeof(devname)); #endif @@ -529,7 +557,7 @@ config_detach(struct device *dev, int flags) } if (rv != 0) { if ((flags & DETACH_FORCE) == 0) - return (rv); + goto done; else panic("config_detach: forced detach of %s failed (%d)", dev->dv_xname, rv); @@ -611,7 +639,12 @@ config_detach(struct device *dev, int flags) /* * Return success. */ - return (0); +done: + mtx_enter(&autoconf_attdet_mtx); + if (++autoconf_attdet == 0) + wakeup(&autoconf_attdet); + mtx_leave(&autoconf_attdet_mtx); + return (rv); } int |