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dc08ffec87
Introduce d_version field in struct cdevsw, this must always be initialized to D_VERSION. Flip sense of D_NOGIANT flag to D_NEEDGIANT, this involves removing four D_NOGIANT flags and adding 145 D_NEEDGIANT flags.
542 lines
15 KiB
C
542 lines
15 KiB
C
/*
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* Copyright (c) 1997, 1998, 1999 Kenneth D. Merry.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/devicestat.h>
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#include <sys/sysctl.h>
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#include <sys/malloc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/conf.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <machine/atomic.h>
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static int devstat_num_devs;
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static long devstat_generation = 1;
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static int devstat_version = DEVSTAT_VERSION;
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static int devstat_current_devnumber;
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static struct mtx devstat_mutex;
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static struct devstatlist device_statq;
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static struct devstat *devstat_alloc(void);
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static void devstat_free(struct devstat *);
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static void devstat_add_entry(struct devstat *ds, const void *dev_name,
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int unit_number, u_int32_t block_size,
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devstat_support_flags flags,
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devstat_type_flags device_type,
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devstat_priority priority);
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/*
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* Allocate a devstat and initialize it
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*/
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struct devstat *
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devstat_new_entry(const void *dev_name,
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int unit_number, u_int32_t block_size,
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devstat_support_flags flags,
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devstat_type_flags device_type,
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devstat_priority priority)
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{
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struct devstat *ds;
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static int once;
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if (!once) {
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STAILQ_INIT(&device_statq);
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mtx_init(&devstat_mutex, "devstat", NULL, MTX_DEF);
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once = 1;
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}
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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ds = devstat_alloc();
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mtx_lock(&devstat_mutex);
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if (unit_number == -1) {
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ds->id = dev_name;
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binuptime(&ds->creation_time);
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devstat_generation++;
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} else {
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devstat_add_entry(ds, dev_name, unit_number, block_size,
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flags, device_type, priority);
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}
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mtx_unlock(&devstat_mutex);
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return (ds);
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}
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/*
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* Take a malloced and zeroed devstat structure given to us, fill it in
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* and add it to the queue of devices.
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*/
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static void
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devstat_add_entry(struct devstat *ds, const void *dev_name,
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int unit_number, u_int32_t block_size,
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devstat_support_flags flags,
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devstat_type_flags device_type,
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devstat_priority priority)
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{
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struct devstatlist *devstat_head;
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struct devstat *ds_tmp;
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mtx_assert(&devstat_mutex, MA_OWNED);
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devstat_num_devs++;
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devstat_head = &device_statq;
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/*
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* Priority sort. Each driver passes in its priority when it adds
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* its devstat entry. Drivers are sorted first by priority, and
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* then by probe order.
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*
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* For the first device, we just insert it, since the priority
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* doesn't really matter yet. Subsequent devices are inserted into
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* the list using the order outlined above.
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*/
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if (devstat_num_devs == 1)
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STAILQ_INSERT_TAIL(devstat_head, ds, dev_links);
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else {
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STAILQ_FOREACH(ds_tmp, devstat_head, dev_links) {
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struct devstat *ds_next;
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ds_next = STAILQ_NEXT(ds_tmp, dev_links);
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/*
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* If we find a break between higher and lower
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* priority items, and if this item fits in the
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* break, insert it. This also applies if the
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* "lower priority item" is the end of the list.
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*/
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if ((priority <= ds_tmp->priority)
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&& ((ds_next == NULL)
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|| (priority > ds_next->priority))) {
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STAILQ_INSERT_AFTER(devstat_head, ds_tmp, ds,
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dev_links);
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break;
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} else if (priority > ds_tmp->priority) {
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/*
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* If this is the case, we should be able
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* to insert ourselves at the head of the
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* list. If we can't, something is wrong.
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*/
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if (ds_tmp == STAILQ_FIRST(devstat_head)) {
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STAILQ_INSERT_HEAD(devstat_head,
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ds, dev_links);
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break;
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} else {
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STAILQ_INSERT_TAIL(devstat_head,
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ds, dev_links);
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printf("devstat_add_entry: HELP! "
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"sorting problem detected "
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"for name %p unit %d\n",
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dev_name, unit_number);
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break;
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}
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}
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}
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}
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ds->device_number = devstat_current_devnumber++;
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ds->unit_number = unit_number;
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strlcpy(ds->device_name, dev_name, DEVSTAT_NAME_LEN);
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ds->block_size = block_size;
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ds->flags = flags;
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ds->device_type = device_type;
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ds->priority = priority;
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binuptime(&ds->creation_time);
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devstat_generation++;
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}
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/*
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* Remove a devstat structure from the list of devices.
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*/
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void
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devstat_remove_entry(struct devstat *ds)
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{
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struct devstatlist *devstat_head;
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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if (ds == NULL)
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return;
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mtx_lock(&devstat_mutex);
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devstat_head = &device_statq;
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/* Remove this entry from the devstat queue */
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atomic_add_acq_int(&ds->sequence1, 1);
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if (ds->id == NULL) {
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devstat_num_devs--;
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STAILQ_REMOVE(devstat_head, ds, devstat, dev_links);
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}
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devstat_free(ds);
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devstat_generation++;
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mtx_unlock(&devstat_mutex);
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}
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/*
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* Record a transaction start.
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*
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* See comments for devstat_end_transaction(). Ordering is very important
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* here.
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*/
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void
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devstat_start_transaction(struct devstat *ds, struct bintime *now)
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{
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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/* sanity check */
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if (ds == NULL)
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return;
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atomic_add_acq_int(&ds->sequence1, 1);
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/*
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* We only want to set the start time when we are going from idle
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* to busy. The start time is really the start of the latest busy
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* period.
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*/
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if (ds->start_count == ds->end_count) {
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if (now != NULL)
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ds->busy_from = *now;
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else
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binuptime(&ds->busy_from);
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}
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ds->start_count++;
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atomic_add_rel_int(&ds->sequence0, 1);
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}
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void
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devstat_start_transaction_bio(struct devstat *ds, struct bio *bp)
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{
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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/* sanity check */
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if (ds == NULL)
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return;
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binuptime(&bp->bio_t0);
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devstat_start_transaction(ds, &bp->bio_t0);
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}
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/*
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* Record the ending of a transaction, and incrment the various counters.
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*
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* Ordering in this function, and in devstat_start_transaction() is VERY
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* important. The idea here is to run without locks, so we are very
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* careful to only modify some fields on the way "down" (i.e. at
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* transaction start) and some fields on the way "up" (i.e. at transaction
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* completion). One exception is busy_from, which we only modify in
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* devstat_start_transaction() when there are no outstanding transactions,
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* and thus it can't be modified in devstat_end_transaction()
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* simultaneously.
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*
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* The sequence0 and sequence1 fields are provided to enable an application
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* spying on the structures with mmap(2) to tell when a structure is in a
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* consistent state or not.
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*
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* For this to work 100% reliably, it is important that the two fields
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* are at opposite ends of the structure and that they are incremented
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* in the opposite order of how a memcpy(3) in userland would copy them.
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* We assume that the copying happens front to back, but there is actually
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* no way short of writing your own memcpy(3) replacement to guarantee
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* this will be the case.
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*
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* In addition to this, being a kind of locks, they must be updated with
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* atomic instructions using appropriate memory barriers.
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*/
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void
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devstat_end_transaction(struct devstat *ds, u_int32_t bytes,
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devstat_tag_type tag_type, devstat_trans_flags flags,
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struct bintime *now, struct bintime *then)
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{
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struct bintime dt, lnow;
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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/* sanity check */
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if (ds == NULL)
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return;
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if (now == NULL) {
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now = &lnow;
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binuptime(now);
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}
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atomic_add_acq_int(&ds->sequence1, 1);
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/* Update byte and operations counts */
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ds->bytes[flags] += bytes;
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ds->operations[flags]++;
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/*
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* Keep a count of the various tag types sent.
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*/
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if ((ds->flags & DEVSTAT_NO_ORDERED_TAGS) == 0 &&
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tag_type != DEVSTAT_TAG_NONE)
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ds->tag_types[tag_type]++;
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if (then != NULL) {
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/* Update duration of operations */
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dt = *now;
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bintime_sub(&dt, then);
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bintime_add(&ds->duration[flags], &dt);
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}
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/* Accumulate busy time */
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dt = *now;
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bintime_sub(&dt, &ds->busy_from);
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bintime_add(&ds->busy_time, &dt);
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ds->busy_from = *now;
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ds->end_count++;
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atomic_add_rel_int(&ds->sequence0, 1);
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}
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void
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devstat_end_transaction_bio(struct devstat *ds, struct bio *bp)
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{
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devstat_trans_flags flg;
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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/* sanity check */
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if (ds == NULL)
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return;
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if (bp->bio_cmd == BIO_DELETE)
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flg = DEVSTAT_FREE;
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else if (bp->bio_cmd == BIO_READ)
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flg = DEVSTAT_READ;
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else if (bp->bio_cmd == BIO_WRITE)
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flg = DEVSTAT_WRITE;
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else
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flg = DEVSTAT_NO_DATA;
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devstat_end_transaction(ds, bp->bio_bcount - bp->bio_resid,
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DEVSTAT_TAG_SIMPLE, flg, NULL, &bp->bio_t0);
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}
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/*
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* This is the sysctl handler for the devstat package. The data pushed out
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* on the kern.devstat.all sysctl variable consists of the current devstat
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* generation number, and then an array of devstat structures, one for each
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* device in the system.
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*
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* This is more cryptic that obvious, but basically we neither can nor
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* want to hold the devstat_mutex for any amount of time, so we grab it
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* only when we need to and keep an eye on devstat_generation all the time.
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*/
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static int
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sysctl_devstat(SYSCTL_HANDLER_ARGS)
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{
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int error;
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long mygen;
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struct devstat *nds;
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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/*
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* XXX devstat_generation should really be "volatile" but that
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* XXX freaks out the sysctl macro below. The places where we
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* XXX change it and inspect it are bracketed in the mutex which
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* XXX guarantees us proper write barriers. I don't belive the
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* XXX compiler is allowed to optimize mygen away across calls
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* XXX to other functions, so the following is belived to be safe.
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*/
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mygen = devstat_generation;
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error = SYSCTL_OUT(req, &mygen, sizeof(mygen));
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if (devstat_num_devs == 0)
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return(0);
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if (error != 0)
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return (error);
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mtx_lock(&devstat_mutex);
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nds = STAILQ_FIRST(&device_statq);
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if (mygen != devstat_generation)
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error = EBUSY;
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mtx_unlock(&devstat_mutex);
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if (error != 0)
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return (error);
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for (;nds != NULL;) {
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error = SYSCTL_OUT(req, nds, sizeof(struct devstat));
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if (error != 0)
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return (error);
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mtx_lock(&devstat_mutex);
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if (mygen != devstat_generation)
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error = EBUSY;
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else
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nds = STAILQ_NEXT(nds, dev_links);
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mtx_unlock(&devstat_mutex);
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if (error != 0)
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return (error);
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}
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return(error);
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}
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/*
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* Sysctl entries for devstat. The first one is a node that all the rest
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* hang off of.
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*/
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SYSCTL_NODE(_kern, OID_AUTO, devstat, CTLFLAG_RD, 0, "Device Statistics");
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SYSCTL_PROC(_kern_devstat, OID_AUTO, all, CTLFLAG_RD|CTLTYPE_OPAQUE,
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0, 0, sysctl_devstat, "S,devstat", "All devices in the devstat list");
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/*
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* Export the number of devices in the system so that userland utilities
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* can determine how much memory to allocate to hold all the devices.
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*/
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SYSCTL_INT(_kern_devstat, OID_AUTO, numdevs, CTLFLAG_RD,
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&devstat_num_devs, 0, "Number of devices in the devstat list");
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SYSCTL_LONG(_kern_devstat, OID_AUTO, generation, CTLFLAG_RD,
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&devstat_generation, 0, "Devstat list generation");
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SYSCTL_INT(_kern_devstat, OID_AUTO, version, CTLFLAG_RD,
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&devstat_version, 0, "Devstat list version number");
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/*
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* Allocator for struct devstat structures. We sub-allocate these from pages
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* which we get from malloc. These pages are exported for mmap(2)'ing through
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* a miniature device driver
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*/
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#define statsperpage (PAGE_SIZE / sizeof(struct devstat))
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static d_mmap_t devstat_mmap;
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static struct cdevsw devstat_cdevsw = {
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.d_version = D_VERSION,
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.d_flags = D_NEEDGIANT,
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.d_mmap = devstat_mmap,
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.d_name = "devstat",
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};
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struct statspage {
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TAILQ_ENTRY(statspage) list;
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struct devstat *stat;
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u_int nfree;
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};
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static TAILQ_HEAD(, statspage) pagelist = TAILQ_HEAD_INITIALIZER(pagelist);
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static MALLOC_DEFINE(M_DEVSTAT, "devstat", "Device statistics");
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static int
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devstat_mmap(dev_t dev, vm_offset_t offset, vm_paddr_t *paddr, int nprot)
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{
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struct statspage *spp;
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if (nprot != VM_PROT_READ)
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return (-1);
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TAILQ_FOREACH(spp, &pagelist, list) {
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if (offset == 0) {
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*paddr = vtophys(spp->stat);
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return (0);
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}
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offset -= PAGE_SIZE;
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}
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return (-1);
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}
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static struct devstat *
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devstat_alloc(void)
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{
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struct devstat *dsp;
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struct statspage *spp;
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u_int u;
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static int once;
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mtx_assert(&devstat_mutex, MA_NOTOWNED);
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if (!once) {
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make_dev(&devstat_cdevsw, 0,
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UID_ROOT, GID_WHEEL, 0400, DEVSTAT_DEVICE_NAME);
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once = 1;
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}
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mtx_lock(&devstat_mutex);
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for (;;) {
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TAILQ_FOREACH(spp, &pagelist, list) {
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if (spp->nfree > 0)
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break;
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}
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if (spp != NULL)
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break;
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/*
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* We had no free slot in any of our pages, drop the mutex
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* and get another page. In theory we could have more than
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* one process doing this at the same time and consequently
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* we may allocate more pages than we will need. That is
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* Just Too Bad[tm], we can live with that.
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*/
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mtx_unlock(&devstat_mutex);
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spp = malloc(sizeof *spp, M_DEVSTAT, M_ZERO | M_WAITOK);
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spp->stat = malloc(PAGE_SIZE, M_DEVSTAT, M_ZERO | M_WAITOK);
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spp->nfree = statsperpage;
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mtx_lock(&devstat_mutex);
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/*
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* It would make more sense to add the new page at the head
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* but the order on the list determine the sequence of the
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* mapping so we can't do that.
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*/
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TAILQ_INSERT_TAIL(&pagelist, spp, list);
|
|
}
|
|
dsp = spp->stat;
|
|
for (u = 0; u < statsperpage; u++) {
|
|
if (dsp->allocated == 0)
|
|
break;
|
|
dsp++;
|
|
}
|
|
spp->nfree--;
|
|
dsp->allocated = 1;
|
|
mtx_unlock(&devstat_mutex);
|
|
return (dsp);
|
|
}
|
|
|
|
static void
|
|
devstat_free(struct devstat *dsp)
|
|
{
|
|
struct statspage *spp;
|
|
|
|
mtx_assert(&devstat_mutex, MA_OWNED);
|
|
bzero(dsp, sizeof *dsp);
|
|
TAILQ_FOREACH(spp, &pagelist, list) {
|
|
if (dsp >= spp->stat && dsp < (spp->stat + statsperpage)) {
|
|
spp->nfree++;
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
SYSCTL_INT(_debug_sizeof, OID_AUTO, devstat, CTLFLAG_RD,
|
|
0, sizeof(struct devstat), "sizeof(struct devstat)");
|