a795f8bbaa
help track down bugs in the devstat implementation in various drivers. (i.e., any situation where the driver does not call the devstat routines once and only once for each transaction initiation and completion) Prompted by: msmith
248 lines
7.0 KiB
C
248 lines
7.0 KiB
C
/*
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* Copyright (c) 1997, 1998 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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* $Id: subr_devstat.c,v 1.2 1998/09/20 00:10:39 ken Exp $
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*/
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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/time.h>
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#include <sys/types.h>
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#include <sys/sysctl.h>
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#include <sys/devicestat.h>
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static int devstat_num_devs;
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static long devstat_generation;
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static int devstat_version = DEVSTAT_VERSION;
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static int devstat_current_devnumber;
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STAILQ_HEAD(devstatlist, devstat) device_statq;
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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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void
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devstat_add_entry(struct devstat *ds, char *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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{
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int s;
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struct devstatlist *devstat_head;
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if (ds == NULL)
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return;
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if (devstat_num_devs == 0)
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STAILQ_INIT(&device_statq);
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devstat_generation++;
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devstat_num_devs++;
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devstat_head = &device_statq;
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STAILQ_INSERT_TAIL(devstat_head, ds, dev_links);
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ds->device_number = devstat_current_devnumber++;
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ds->unit_number = unit_number;
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strncpy(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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s = splclock();
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getmicrotime(&ds->dev_creation_time);
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splx(s);
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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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if (ds == NULL)
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return;
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devstat_generation++;
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devstat_num_devs--;
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devstat_head = &device_statq;
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/* Remove this entry from the devstat queue */
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STAILQ_REMOVE(devstat_head, ds, devstat, dev_links);
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}
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/*
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* Record a transaction start.
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*/
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void
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devstat_start_transaction(struct devstat *ds)
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{
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int s;
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/* sanity check */
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if (ds == NULL)
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return;
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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->busy_count == 0) {
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s = splclock();
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getmicrouptime(&ds->start_time);
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splx(s);
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}
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ds->busy_count++;
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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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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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{
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int s;
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struct timeval busy_time;
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/* sanity check */
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if (ds == NULL)
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return;
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s = splclock();
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getmicrouptime(&ds->last_comp_time);
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splx(s);
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ds->busy_count--;
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/*
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* There might be some transactions (DEVSTAT_NO_DATA) that don't
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* transfer any data.
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*/
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if (flags == DEVSTAT_READ) {
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ds->bytes_read += bytes;
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ds->num_reads++;
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} else if (flags == DEVSTAT_WRITE) {
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ds->bytes_written += bytes;
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ds->num_writes++;
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} else
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ds->num_other++;
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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 (tag_type != DEVSTAT_TAG_NONE)
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ds->tag_types[tag_type]++;
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/*
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* We only update the busy time when we go idle. Otherwise, this
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* calculation would require many more clock cycles.
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*/
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if (ds->busy_count == 0) {
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/* Calculate how long we were busy */
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busy_time = ds->last_comp_time;
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timevalsub(&busy_time, &ds->start_time);
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/* Add our busy time to the total busy time. */
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timevaladd(&ds->busy_time, &busy_time);
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} else if (ds->busy_count < 0)
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printf("devstat_end_transaction: HELP!! busy_count "
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"for %s%d is < 0 (%d)!\n", ds->device_name,
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ds->unit_number, ds->busy_count);
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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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* I'm really not too fond of this method of doing things, but there really
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* aren't that many alternatives. We must have some method of making sure
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* that the generation number the user gets corresponds with the data the
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* user gets. If the user makes a separate sysctl call to get the
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* generation, and then a sysctl call to get the device statistics, the
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* device list could have changed in that brief period of time. By
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* supplying the generation number along with the statistics output, we can
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* guarantee that the generation number and the statistics match up.
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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, i;
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struct devstat *nds;
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struct devstatlist *devstat_head;
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if (devstat_num_devs == 0)
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return(EINVAL);
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error = 0;
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devstat_head = &device_statq;
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/*
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* First push out the generation number.
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*/
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error = SYSCTL_OUT(req, &devstat_generation, sizeof(long));
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/*
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* Now push out all the devices.
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*/
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for (i = 0, nds = devstat_head->stqh_first;
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(nds != NULL) && (i < devstat_num_devs) && (error == 0);
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nds = nds->dev_links.stqe_next, i++)
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error = SYSCTL_OUT(req, nds, sizeof(struct devstat));
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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");
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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, &devstat_num_devs,
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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, &devstat_version,
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0, "Devstat list version number");
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