diff options
Diffstat (limited to 'sys/contrib/opensolaris/uts/common/os/callb.c')
-rw-r--r-- | sys/contrib/opensolaris/uts/common/os/callb.c | 363 |
1 files changed, 363 insertions, 0 deletions
diff --git a/sys/contrib/opensolaris/uts/common/os/callb.c b/sys/contrib/opensolaris/uts/common/os/callb.c new file mode 100644 index 0000000..9bfae13 --- /dev/null +++ b/sys/contrib/opensolaris/uts/common/os/callb.c @@ -0,0 +1,363 @@ +/* + * CDDL HEADER START + * + * The contents of this file are subject to the terms of the + * Common Development and Distribution License, Version 1.0 only + * (the "License"). You may not use this file except in compliance + * with the License. + * + * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE + * or http://www.opensolaris.org/os/licensing. + * See the License for the specific language governing permissions + * and limitations under the License. + * + * When distributing Covered Code, include this CDDL HEADER in each + * file and include the License file at usr/src/OPENSOLARIS.LICENSE. + * If applicable, add the following below this CDDL HEADER, with the + * fields enclosed by brackets "[]" replaced with your own identifying + * information: Portions Copyright [yyyy] [name of copyright owner] + * + * CDDL HEADER END + */ +/* + * Copyright 2004 Sun Microsystems, Inc. All rights reserved. + * Use is subject to license terms. + */ + +#pragma ident "%Z%%M% %I% %E% SMI" + +#include <sys/param.h> +#include <sys/types.h> +#include <sys/time.h> +#include <sys/sysmacros.h> +#include <sys/systm.h> +#include <sys/proc.h> +#include <sys/mutex.h> +#include <sys/condvar.h> +#include <sys/callb.h> +#include <sys/kmem.h> +#include <sys/cmn_err.h> +#include <sys/debug.h> +#include <sys/kobj.h> +#include <sys/systm.h> /* for delay() */ +#include <sys/taskq.h> /* For TASKQ_NAMELEN */ +#include <sys/kernel.h> + +#define CB_MAXNAME TASKQ_NAMELEN + +/* + * The callb mechanism provides generic event scheduling/echoing. + * A callb function is registered and called on behalf of the event. + */ +typedef struct callb { + struct callb *c_next; /* next in class or on freelist */ + kthread_id_t c_thread; /* ptr to caller's thread struct */ + char c_flag; /* info about the callb state */ + uchar_t c_class; /* this callb's class */ + kcondvar_t c_done_cv; /* signal callb completion */ + boolean_t (*c_func)(); /* cb function: returns true if ok */ + void *c_arg; /* arg to c_func */ + char c_name[CB_MAXNAME+1]; /* debug:max func name length */ +} callb_t; + +/* + * callb c_flag bitmap definitions + */ +#define CALLB_FREE 0x0 +#define CALLB_TAKEN 0x1 +#define CALLB_EXECUTING 0x2 + +/* + * Basic structure for a callb table. + * All callbs are organized into different class groups described + * by ct_class array. + * The callbs within a class are single-linked and normally run by a + * serial execution. + */ +typedef struct callb_table { + kmutex_t ct_lock; /* protect all callb states */ + callb_t *ct_freelist; /* free callb structures */ + int ct_busy; /* != 0 prevents additions */ + kcondvar_t ct_busy_cv; /* to wait for not busy */ + int ct_ncallb; /* num of callbs allocated */ + callb_t *ct_first_cb[NCBCLASS]; /* ptr to 1st callb in a class */ +} callb_table_t; + +int callb_timeout_sec = CPR_KTHREAD_TIMEOUT_SEC; + +static callb_id_t callb_add_common(boolean_t (*)(void *, int), + void *, int, char *, kthread_id_t); + +static callb_table_t callb_table; /* system level callback table */ +static callb_table_t *ct = &callb_table; +static kmutex_t callb_safe_mutex; +callb_cpr_t callb_cprinfo_safe = { + &callb_safe_mutex, CALLB_CPR_ALWAYS_SAFE, 0, 0, 0 }; + +/* + * Init all callb tables in the system. + */ +void +callb_init(void *dummy __unused) +{ + callb_table.ct_busy = 0; /* mark table open for additions */ + mutex_init(&callb_safe_mutex, NULL, MUTEX_DEFAULT, NULL); + mutex_init(&callb_table.ct_lock, NULL, MUTEX_DEFAULT, NULL); +} + +void +callb_fini(void *dummy __unused) +{ + callb_t *cp; + + mutex_enter(&ct->ct_lock); + while ((cp = ct->ct_freelist) != NULL) { + ct->ct_freelist = cp->c_next; + ct->ct_ncallb--; + kmem_free(cp, sizeof (callb_t)); + } + ASSERT(ct->ct_ncallb == 0); + mutex_exit(&ct->ct_lock); + mutex_destroy(&callb_safe_mutex); + mutex_destroy(&callb_table.ct_lock); +} + +/* + * callout_add() is called to register func() be called later. + */ +static callb_id_t +callb_add_common(boolean_t (*func)(void *arg, int code), + void *arg, int class, char *name, kthread_id_t t) +{ + callb_t *cp; + + ASSERT(class < NCBCLASS); + + mutex_enter(&ct->ct_lock); + while (ct->ct_busy) + cv_wait(&ct->ct_busy_cv, &ct->ct_lock); + if ((cp = ct->ct_freelist) == NULL) { + ct->ct_ncallb++; + cp = (callb_t *)kmem_zalloc(sizeof (callb_t), KM_SLEEP); + } + ct->ct_freelist = cp->c_next; + cp->c_thread = t; + cp->c_func = func; + cp->c_arg = arg; + cp->c_class = (uchar_t)class; + cp->c_flag |= CALLB_TAKEN; +#ifdef DEBUG + if (strlen(name) > CB_MAXNAME) + cmn_err(CE_WARN, "callb_add: name of callback function '%s' " + "too long -- truncated to %d chars", + name, CB_MAXNAME); +#endif + (void) strncpy(cp->c_name, name, CB_MAXNAME); + cp->c_name[CB_MAXNAME] = '\0'; + + /* + * Insert the new callb at the head of its class list. + */ + cp->c_next = ct->ct_first_cb[class]; + ct->ct_first_cb[class] = cp; + + mutex_exit(&ct->ct_lock); + return ((callb_id_t)cp); +} + +/* + * The default function to add an entry to the callback table. Since + * it uses curthread as the thread identifier to store in the table, + * it should be used for the normal case of a thread which is calling + * to add ITSELF to the table. + */ +callb_id_t +callb_add(boolean_t (*func)(void *arg, int code), + void *arg, int class, char *name) +{ + return (callb_add_common(func, arg, class, name, curthread)); +} + +/* + * A special version of callb_add() above for use by threads which + * might be adding an entry to the table on behalf of some other + * thread (for example, one which is constructed but not yet running). + * In this version the thread id is an argument. + */ +callb_id_t +callb_add_thread(boolean_t (*func)(void *arg, int code), + void *arg, int class, char *name, kthread_id_t t) +{ + return (callb_add_common(func, arg, class, name, t)); +} + +/* + * callout_delete() is called to remove an entry identified by id + * that was originally placed there by a call to callout_add(). + * return -1 if fail to delete a callb entry otherwise return 0. + */ +int +callb_delete(callb_id_t id) +{ + callb_t **pp; + callb_t *me = (callb_t *)id; + + mutex_enter(&ct->ct_lock); + + for (;;) { + pp = &ct->ct_first_cb[me->c_class]; + while (*pp != NULL && *pp != me) + pp = &(*pp)->c_next; + +#ifdef DEBUG + if (*pp != me) { + cmn_err(CE_WARN, "callb delete bogus entry 0x%p", + (void *)me); + mutex_exit(&ct->ct_lock); + return (-1); + } +#endif /* DEBUG */ + + /* + * It is not allowed to delete a callb in the middle of + * executing otherwise, the callb_execute() will be confused. + */ + if (!(me->c_flag & CALLB_EXECUTING)) + break; + + cv_wait(&me->c_done_cv, &ct->ct_lock); + } + /* relink the class list */ + *pp = me->c_next; + + /* clean up myself and return the free callb to the head of freelist */ + me->c_flag = CALLB_FREE; + me->c_next = ct->ct_freelist; + ct->ct_freelist = me; + + mutex_exit(&ct->ct_lock); + return (0); +} + +/* + * class: indicates to execute all callbs in the same class; + * code: optional argument for the callb functions. + * return: = 0: success + * != 0: ptr to string supplied when callback was registered + */ +void * +callb_execute_class(int class, int code) +{ + callb_t *cp; + void *ret = NULL; + + ASSERT(class < NCBCLASS); + + mutex_enter(&ct->ct_lock); + + for (cp = ct->ct_first_cb[class]; + cp != NULL && ret == 0; cp = cp->c_next) { + while (cp->c_flag & CALLB_EXECUTING) + cv_wait(&cp->c_done_cv, &ct->ct_lock); + /* + * cont if the callb is deleted while we're sleeping + */ + if (cp->c_flag == CALLB_FREE) + continue; + cp->c_flag |= CALLB_EXECUTING; + +#ifdef CALLB_DEBUG + printf("callb_execute: name=%s func=%p arg=%p\n", + cp->c_name, (void *)cp->c_func, (void *)cp->c_arg); +#endif /* CALLB_DEBUG */ + + mutex_exit(&ct->ct_lock); + /* If callback function fails, pass back client's name */ + if (!(*cp->c_func)(cp->c_arg, code)) + ret = cp->c_name; + mutex_enter(&ct->ct_lock); + + cp->c_flag &= ~CALLB_EXECUTING; + cv_broadcast(&cp->c_done_cv); + } + mutex_exit(&ct->ct_lock); + return (ret); +} + +/* + * callers make sure no recursive entries to this func. + * dp->cc_lockp is registered by callb_add to protect callb_cpr_t structure. + * + * When calling to stop a kernel thread (code == CB_CODE_CPR_CHKPT) we + * use a cv_timedwait() in case the kernel thread is blocked. + * + * Note that this is a generic callback handler for daemon CPR and + * should NOT be changed to accommodate any specific requirement in a daemon. + * Individual daemons that require changes to the handler shall write + * callback routines in their own daemon modules. + */ +boolean_t +callb_generic_cpr(void *arg, int code) +{ + callb_cpr_t *cp = (callb_cpr_t *)arg; + clock_t ret = 0; /* assume success */ + + mutex_enter(cp->cc_lockp); + + switch (code) { + case CB_CODE_CPR_CHKPT: + cp->cc_events |= CALLB_CPR_START; + while (!(cp->cc_events & CALLB_CPR_SAFE)) + /* cv_timedwait() returns -1 if it times out. */ + if ((ret = cv_timedwait(&cp->cc_callb_cv, + cp->cc_lockp, + callb_timeout_sec * hz)) == -1) + break; + break; + + case CB_CODE_CPR_RESUME: + cp->cc_events &= ~CALLB_CPR_START; + cv_signal(&cp->cc_stop_cv); + break; + } + mutex_exit(cp->cc_lockp); + return (ret != -1); +} + +/* + * The generic callback function associated with kernel threads which + * are always considered safe. + */ +/* ARGSUSED */ +boolean_t +callb_generic_cpr_safe(void *arg, int code) +{ + return (B_TRUE); +} +/* + * Prevent additions to callback table. + */ +void +callb_lock_table(void) +{ + mutex_enter(&ct->ct_lock); + ASSERT(ct->ct_busy == 0); + ct->ct_busy = 1; + mutex_exit(&ct->ct_lock); +} + +/* + * Allow additions to callback table. + */ +void +callb_unlock_table(void) +{ + mutex_enter(&ct->ct_lock); + ASSERT(ct->ct_busy != 0); + ct->ct_busy = 0; + cv_broadcast(&ct->ct_busy_cv); + mutex_exit(&ct->ct_lock); +} + +SYSINIT(sol_callb, SI_SUB_DRIVERS, SI_ORDER_FIRST, callb_init, NULL) +SYSUNINIT(sol_callb, SI_SUB_DRIVERS, SI_ORDER_FIRST, callb_fini, NULL); |