NetBSD/sys/kern/subr_disk.c

1008 lines
27 KiB
C

/* $NetBSD: subr_disk.c,v 1.41 2002/07/23 14:00:16 hannken Exp $ */
/*-
* Copyright (c) 1996, 1997, 1999, 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ufs_disksubr.c 8.5 (Berkeley) 1/21/94
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.41 2002/07/23 14:00:16 hannken Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/buf.h>
#include <sys/syslog.h>
#include <sys/disklabel.h>
#include <sys/disk.h>
#include <sys/sysctl.h>
/*
* A global list of all disks attached to the system. May grow or
* shrink over time.
*/
struct disklist_head disklist; /* TAILQ_HEAD */
int disk_count; /* number of drives in global disklist */
struct simplelock disklist_slock = SIMPLELOCK_INITIALIZER;
/*
* XXX This interface will be removed in the near future!
*
* Seek sort for disks. We depend on the driver which calls us using b_resid
* as the current cylinder number.
*
* The argument bufq is an I/O queue for the device, on which there are
* actually two queues, sorted in ascending cylinder order. The first
* queue holds those requests which are positioned after the current
* cylinder (in the first request); the second holds requests which came
* in after their cylinder number was passed. Thus we implement a one-way
* scan, retracting after reaching the end of the drive to the first request
* on the second queue, at which time it becomes the first queue.
*
* A one-way scan is natural because of the way UNIX read-ahead blocks are
* allocated.
*
* This is further adjusted by any `barriers' which may exist in the queue.
* The bufq points to the last such ordered request.
*/
void
disksort_cylinder(struct buf_queue *bufq, struct buf *bp)
{
struct buf *bq, *nbq;
/*
* If there are ordered requests on the queue, we must start
* the elevator sort after the last of these.
*/
if ((bq = bufq->bq_barrier) == NULL)
bq = BUFQ_FIRST(bufq);
/*
* If the queue is empty, of if it's an ordered request,
* it's easy; we just go on the end.
*/
if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
BUFQ_INSERT_TAIL(bufq, bp);
return;
}
/*
* If we lie after the first (currently active) request, then we
* must locate the second request list and add ourselves to it.
*/
if (bp->b_cylinder < bq->b_cylinder ||
(bp->b_cylinder == bq->b_cylinder &&
bp->b_rawblkno < bq->b_rawblkno)) {
while ((nbq = BUFQ_NEXT(bq)) != NULL) {
/*
* Check for an ``inversion'' in the normally ascending
* cylinder numbers, indicating the start of the second
* request list.
*/
if (nbq->b_cylinder < bq->b_cylinder) {
/*
* Search the second request list for the first
* request at a larger cylinder number. We go
* before that; if there is no such request, we
* go at end.
*/
do {
if (bp->b_cylinder < nbq->b_cylinder)
goto insert;
if (bp->b_cylinder == nbq->b_cylinder &&
bp->b_rawblkno < nbq->b_rawblkno)
goto insert;
bq = nbq;
} while ((nbq = BUFQ_NEXT(bq)) != NULL);
goto insert; /* after last */
}
bq = nbq;
}
/*
* No inversions... we will go after the last, and
* be the first request in the second request list.
*/
goto insert;
}
/*
* Request is at/after the current request...
* sort in the first request list.
*/
while ((nbq = BUFQ_NEXT(bq)) != NULL) {
/*
* We want to go after the current request if there is an
* inversion after it (i.e. it is the end of the first
* request list), or if the next request is a larger cylinder
* than our request.
*/
if (nbq->b_cylinder < bq->b_cylinder ||
bp->b_cylinder < nbq->b_cylinder ||
(bp->b_cylinder == nbq->b_cylinder &&
bp->b_rawblkno < nbq->b_rawblkno))
goto insert;
bq = nbq;
}
/*
* Neither a second list nor a larger request... we go at the end of
* the first list, which is the same as the end of the whole schebang.
*/
insert: BUFQ_INSERT_AFTER(bufq, bq, bp);
}
/*
* Seek sort for disks. This version sorts based on b_rawblkno, which
* indicates the block number.
*
* As before, there are actually two queues, sorted in ascendening block
* order. The first queue holds those requests which are positioned after
* the current block (in the first request); the second holds requests which
* came in after their block number was passed. Thus we implement a one-way
* scan, retracting after reaching the end of the driver to the first request
* on the second queue, at which time it becomes the first queue.
*
* A one-way scan is natural because of the way UNIX read-ahead blocks are
* allocated.
*
* This is further adjusted by any `barriers' which may exist in the queue.
* The bufq points to the last such ordered request.
*/
void
disksort_blkno(struct buf_queue *bufq, struct buf *bp)
{
struct buf *bq, *nbq;
/*
* If there are ordered requests on the queue, we must start
* the elevator sort after the last of these.
*/
if ((bq = bufq->bq_barrier) == NULL)
bq = BUFQ_FIRST(bufq);
/*
* If the queue is empty, or if it's an ordered request,
* it's easy; we just go on the end.
*/
if (bq == NULL || (bp->b_flags & B_ORDERED) != 0) {
BUFQ_INSERT_TAIL(bufq, bp);
return;
}
/*
* If we lie after the first (currently active) request, then we
* must locate the second request list and add ourselves to it.
*/
if (bp->b_rawblkno < bq->b_rawblkno) {
while ((nbq = BUFQ_NEXT(bq)) != NULL) {
/*
* Check for an ``inversion'' in the normally ascending
* block numbers, indicating the start of the second
* request list.
*/
if (nbq->b_rawblkno < bq->b_rawblkno) {
/*
* Search the second request list for the first
* request at a larger block number. We go
* after that; if there is no such request, we
* go at the end.
*/
do {
if (bp->b_rawblkno < nbq->b_rawblkno)
goto insert;
bq = nbq;
} while ((nbq = BUFQ_NEXT(bq)) != NULL);
goto insert; /* after last */
}
bq = nbq;
}
/*
* No inversions... we will go after the last, and
* be the first request in the second request list.
*/
goto insert;
}
/*
* Request is at/after the current request...
* sort in the first request list.
*/
while ((nbq = BUFQ_NEXT(bq)) != NULL) {
/*
* We want to go after the current request if there is an
* inversion after it (i.e. it is the end of the first
* request list), or if the next request is a larger cylinder
* than our request.
*/
if (nbq->b_rawblkno < bq->b_rawblkno ||
bp->b_rawblkno < nbq->b_rawblkno)
goto insert;
bq = nbq;
}
/*
* Neither a second list nor a larger request... we go at the end of
* the first list, which is the same as the end of the whole schebang.
*/
insert: BUFQ_INSERT_AFTER(bufq, bq, bp);
}
/*
* Seek non-sort for disks. This version simply inserts requests at
* the tail of the queue.
*/
void
disksort_tail(struct buf_queue *bufq, struct buf *bp)
{
BUFQ_INSERT_TAIL(bufq, bp);
}
/*
* XXX End of to be removed interface!
*/
/*
* Compute checksum for disk label.
*/
u_int
dkcksum(struct disklabel *lp)
{
u_short *start, *end;
u_short sum = 0;
start = (u_short *)lp;
end = (u_short *)&lp->d_partitions[lp->d_npartitions];
while (start < end)
sum ^= *start++;
return (sum);
}
/*
* Disk error is the preface to plaintive error messages
* about failing disk transfers. It prints messages of the form
hp0g: hard error reading fsbn 12345 of 12344-12347 (hp0 bn %d cn %d tn %d sn %d)
* if the offset of the error in the transfer and a disk label
* are both available. blkdone should be -1 if the position of the error
* is unknown; the disklabel pointer may be null from drivers that have not
* been converted to use them. The message is printed with printf
* if pri is LOG_PRINTF, otherwise it uses log at the specified priority.
* The message should be completed (with at least a newline) with printf
* or addlog, respectively. There is no trailing space.
*/
void
diskerr(const struct buf *bp, const char *dname, const char *what, int pri,
int blkdone, const struct disklabel *lp)
{
int unit = DISKUNIT(bp->b_dev), part = DISKPART(bp->b_dev);
void (*pr)(const char *, ...);
char partname = 'a' + part;
int sn;
if (pri != LOG_PRINTF) {
static const char fmt[] = "";
log(pri, fmt);
pr = addlog;
} else
pr = printf;
(*pr)("%s%d%c: %s %sing fsbn ", dname, unit, partname, what,
bp->b_flags & B_READ ? "read" : "writ");
sn = bp->b_blkno;
if (bp->b_bcount <= DEV_BSIZE)
(*pr)("%d", sn);
else {
if (blkdone >= 0) {
sn += blkdone;
(*pr)("%d of ", sn);
}
(*pr)("%d-%d", bp->b_blkno,
bp->b_blkno + (bp->b_bcount - 1) / DEV_BSIZE);
}
if (lp && (blkdone >= 0 || bp->b_bcount <= lp->d_secsize)) {
sn += lp->d_partitions[part].p_offset;
(*pr)(" (%s%d bn %d; cn %d", dname, unit, sn,
sn / lp->d_secpercyl);
sn %= lp->d_secpercyl;
(*pr)(" tn %d sn %d)", sn / lp->d_nsectors,
sn % lp->d_nsectors);
}
}
/*
* Initialize the disklist. Called by main() before autoconfiguration.
*/
void
disk_init(void)
{
TAILQ_INIT(&disklist);
disk_count = 0;
}
/*
* Searches the disklist for the disk corresponding to the
* name provided.
*/
struct disk *
disk_find(char *name)
{
struct disk *diskp;
if ((name == NULL) || (disk_count <= 0))
return (NULL);
simple_lock(&disklist_slock);
for (diskp = TAILQ_FIRST(&disklist); diskp != NULL;
diskp = TAILQ_NEXT(diskp, dk_link))
if (strcmp(diskp->dk_name, name) == 0) {
simple_unlock(&disklist_slock);
return (diskp);
}
simple_unlock(&disklist_slock);
return (NULL);
}
/*
* Attach a disk.
*/
void
disk_attach(struct disk *diskp)
{
int s;
/*
* Allocate and initialize the disklabel structures. Note that
* it's not safe to sleep here, since we're probably going to be
* called during autoconfiguration.
*/
diskp->dk_label = malloc(sizeof(struct disklabel), M_DEVBUF, M_NOWAIT);
diskp->dk_cpulabel = malloc(sizeof(struct cpu_disklabel), M_DEVBUF,
M_NOWAIT);
if ((diskp->dk_label == NULL) || (diskp->dk_cpulabel == NULL))
panic("disk_attach: can't allocate storage for disklabel");
memset(diskp->dk_label, 0, sizeof(struct disklabel));
memset(diskp->dk_cpulabel, 0, sizeof(struct cpu_disklabel));
/*
* Set the attached timestamp.
*/
s = splclock();
diskp->dk_attachtime = mono_time;
splx(s);
/*
* Link into the disklist.
*/
simple_lock(&disklist_slock);
TAILQ_INSERT_TAIL(&disklist, diskp, dk_link);
simple_unlock(&disklist_slock);
++disk_count;
}
/*
* Detach a disk.
*/
void
disk_detach(struct disk *diskp)
{
/*
* Remove from the disklist.
*/
if (--disk_count < 0)
panic("disk_detach: disk_count < 0");
simple_lock(&disklist_slock);
TAILQ_REMOVE(&disklist, diskp, dk_link);
simple_unlock(&disklist_slock);
/*
* Free the space used by the disklabel structures.
*/
free(diskp->dk_label, M_DEVBUF);
free(diskp->dk_cpulabel, M_DEVBUF);
}
/*
* Increment a disk's busy counter. If the counter is going from
* 0 to 1, set the timestamp.
*/
void
disk_busy(struct disk *diskp)
{
int s;
/*
* XXX We'd like to use something as accurate as microtime(),
* but that doesn't depend on the system TOD clock.
*/
if (diskp->dk_busy++ == 0) {
s = splclock();
diskp->dk_timestamp = mono_time;
splx(s);
}
}
/*
* Decrement a disk's busy counter, increment the byte count, total busy
* time, and reset the timestamp.
*/
void
disk_unbusy(struct disk *diskp, long bcount)
{
int s;
struct timeval dv_time, diff_time;
if (diskp->dk_busy-- == 0) {
printf("%s: dk_busy < 0\n", diskp->dk_name);
panic("disk_unbusy");
}
s = splclock();
dv_time = mono_time;
splx(s);
timersub(&dv_time, &diskp->dk_timestamp, &diff_time);
timeradd(&diskp->dk_time, &diff_time, &diskp->dk_time);
diskp->dk_timestamp = dv_time;
if (bcount > 0) {
diskp->dk_bytes += bcount;
diskp->dk_xfer++;
}
}
/*
* Reset the metrics counters on the given disk. Note that we cannot
* reset the busy counter, as it may case a panic in disk_unbusy().
* We also must avoid playing with the timestamp information, as it
* may skew any pending transfer results.
*/
void
disk_resetstat(struct disk *diskp)
{
int s = splbio(), t;
diskp->dk_xfer = 0;
diskp->dk_bytes = 0;
t = splclock();
diskp->dk_attachtime = mono_time;
splx(t);
timerclear(&diskp->dk_time);
splx(s);
}
int
sysctl_disknames(void *vwhere, size_t *sizep)
{
char buf[DK_DISKNAMELEN + 1];
char *where = vwhere;
struct disk *diskp;
size_t needed, left, slen;
int error, first;
first = 1;
error = 0;
needed = 0;
left = *sizep;
simple_lock(&disklist_slock);
for (diskp = TAILQ_FIRST(&disklist); diskp != NULL;
diskp = TAILQ_NEXT(diskp, dk_link)) {
if (where == NULL)
needed += strlen(diskp->dk_name) + 1;
else {
memset(buf, 0, sizeof(buf));
if (first) {
strncpy(buf, diskp->dk_name, sizeof(buf));
first = 0;
} else {
buf[0] = ' ';
strncpy(buf + 1, diskp->dk_name,
sizeof(buf) - 1);
}
buf[DK_DISKNAMELEN] = '\0';
slen = strlen(buf);
if (left < slen + 1)
break;
/* +1 to copy out the trailing NUL byte */
error = copyout(buf, where, slen + 1);
if (error)
break;
where += slen;
needed += slen;
left -= slen;
}
}
simple_unlock(&disklist_slock);
*sizep = needed;
return (error);
}
int
sysctl_diskstats(int *name, u_int namelen, void *vwhere, size_t *sizep)
{
struct disk_sysctl sdisk;
struct disk *diskp;
char *where = vwhere;
size_t tocopy, left;
int error;
if (where == NULL) {
*sizep = disk_count * sizeof(struct disk_sysctl);
return (0);
}
if (namelen == 0)
tocopy = sizeof(sdisk);
else
tocopy = name[0];
error = 0;
left = *sizep;
memset(&sdisk, 0, sizeof(sdisk));
*sizep = 0;
simple_lock(&disklist_slock);
TAILQ_FOREACH(diskp, &disklist, dk_link) {
if (left < sizeof(struct disk_sysctl))
break;
strncpy(sdisk.dk_name, diskp->dk_name, sizeof(sdisk.dk_name));
sdisk.dk_xfer = diskp->dk_xfer;
sdisk.dk_seek = diskp->dk_seek;
sdisk.dk_bytes = diskp->dk_bytes;
sdisk.dk_attachtime_sec = diskp->dk_attachtime.tv_sec;
sdisk.dk_attachtime_usec = diskp->dk_attachtime.tv_usec;
sdisk.dk_timestamp_sec = diskp->dk_timestamp.tv_sec;
sdisk.dk_timestamp_usec = diskp->dk_timestamp.tv_usec;
sdisk.dk_time_sec = diskp->dk_time.tv_sec;
sdisk.dk_time_usec = diskp->dk_time.tv_usec;
sdisk.dk_busy = diskp->dk_busy;
error = copyout(&sdisk, where, min(tocopy, sizeof(sdisk)));
if (error)
break;
where += tocopy;
*sizep += tocopy;
left -= tocopy;
}
simple_unlock(&disklist_slock);
return (error);
}
struct bufq_fcfs {
TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
};
struct bufq_disksort {
TAILQ_HEAD(, buf) bq_head; /* actual list of buffers */
};
#define PRIO_READ_BURST 48
#define PRIO_WRITE_REQ 16
struct bufq_prio {
TAILQ_HEAD(, buf) bq_read, bq_write; /* actual list of buffers */
struct buf *bq_write_next; /* next request in bq_write */
struct buf *bq_next; /* current request */
int bq_read_burst; /* # of consecutive reads */
};
/*
* Check if two buf's are in ascending order.
*/
static __inline int
buf_inorder(struct buf *bp, struct buf *bq, int sortby)
{
int r;
if (bp == NULL || bq == NULL)
return(bq == NULL);
if (sortby == BUFQ_SORT_CYLINDER)
r = bp->b_cylinder - bq->b_cylinder;
else
r = 0;
if (r == 0)
r = bp->b_rawblkno - bq->b_rawblkno;
return(r <= 0);
}
/*
* First-come first-served sort for disks.
*
* Requests are appended to the queue without any reordering.
*/
static void
bufq_fcfs_put(struct bufq_state *bufq, struct buf *bp)
{
struct bufq_fcfs *fcfs = bufq->bq_private;
TAILQ_INSERT_TAIL(&fcfs->bq_head, bp, b_actq);
}
static struct buf *
bufq_fcfs_get(struct bufq_state *bufq, int remove)
{
struct bufq_fcfs *fcfs = bufq->bq_private;
struct buf *bp;
bp = TAILQ_FIRST(&fcfs->bq_head);
if (bp != NULL && remove)
TAILQ_REMOVE(&fcfs->bq_head, bp, b_actq);
return(bp);
}
/*
* Seek sort for disks.
*
* There are actually two queues, sorted in ascendening order. The first
* queue holds those requests which are positioned after the current block;
* the second holds requests which came in after their position was passed.
* Thus we implement a one-way scan, retracting after reaching the end of
* the drive to the first request on the second queue, at which time it
* becomes the first queue.
*
* A one-way scan is natural because of the way UNIX read-ahead blocks are
* allocated.
*/
static void
bufq_disksort_put(struct bufq_state *bufq, struct buf *bp)
{
struct bufq_disksort *disksort = bufq->bq_private;
struct buf *bq, *nbq;
int sortby;
sortby = bufq->bq_flags & BUFQ_SORT_MASK;
bq = TAILQ_FIRST(&disksort->bq_head);
/*
* If the queue is empty it's easy; we just go on the end.
*/
if (bq == NULL) {
TAILQ_INSERT_TAIL(&disksort->bq_head, bp, b_actq);
return;
}
/*
* If we lie before the currently active request, then we
* must locate the second request list and add ourselves to it.
*/
if (buf_inorder(bp, bq, sortby)) {
while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) {
/*
* Check for an ``inversion'' in the normally ascending
* block numbers, indicating the start of the second
* request list.
*/
if (buf_inorder(nbq, bq, sortby)) {
/*
* Search the second request list for the first
* request at a larger block number. We go
* after that; if there is no such request, we
* go at the end.
*/
do {
if (buf_inorder(bp, nbq, sortby))
goto insert;
bq = nbq;
} while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL);
goto insert; /* after last */
}
bq = nbq;
}
/*
* No inversions... we will go after the last, and
* be the first request in the second request list.
*/
goto insert;
}
/*
* Request is at/after the current request...
* sort in the first request list.
*/
while ((nbq = TAILQ_NEXT(bq, b_actq)) != NULL) {
/*
* We want to go after the current request if there is an
* inversion after it (i.e. it is the end of the first
* request list), or if the next request is a larger cylinder
* than our request.
*/
if (buf_inorder(nbq, bq, sortby) ||
buf_inorder(bp, nbq, sortby))
goto insert;
bq = nbq;
}
/*
* Neither a second list nor a larger request... we go at the end of
* the first list, which is the same as the end of the whole schebang.
*/
insert: TAILQ_INSERT_AFTER(&disksort->bq_head, bq, bp, b_actq);
}
static struct buf *
bufq_disksort_get(struct bufq_state *bufq, int remove)
{
struct bufq_disksort *disksort = bufq->bq_private;
struct buf *bp;
bp = TAILQ_FIRST(&disksort->bq_head);
if (bp != NULL && remove)
TAILQ_REMOVE(&disksort->bq_head, bp, b_actq);
return(bp);
}
/*
* Seek sort for disks.
*
* There are two queues. The first queue holds read requests; the second
* holds write requests. The read queue is first-come first-served; the
* write queue is sorted in ascendening block order.
* The read queue is processed first. After PRIO_READ_BURST consecutive
* read requests with non-empty write queue PRIO_WRITE_REQ requests from
* the write queue will be processed.
*/
static void
bufq_prio_put(struct bufq_state *bufq, struct buf *bp)
{
struct bufq_prio *prio = bufq->bq_private;
struct buf *bq;
int sortby;
sortby = bufq->bq_flags & BUFQ_SORT_MASK;
/*
* If it's a read request append it to the list.
*/
if ((bp->b_flags & B_READ) == B_READ) {
TAILQ_INSERT_TAIL(&prio->bq_read, bp, b_actq);
return;
}
bq = TAILQ_FIRST(&prio->bq_write);
/*
* If the write list is empty, simply append it to the list.
*/
if (bq == NULL) {
TAILQ_INSERT_TAIL(&prio->bq_write, bp, b_actq);
prio->bq_write_next = bp;
return;
}
/*
* If we lie after the next request, insert after this request.
*/
if (buf_inorder(prio->bq_write_next, bp, sortby))
bq = prio->bq_write_next;
/*
* Search for the first request at a larger block number.
* We go before this request if it exists.
*/
while (bq != NULL && buf_inorder(bq, bp, sortby))
bq = TAILQ_NEXT(bq, b_actq);
if (bq != NULL)
TAILQ_INSERT_BEFORE(bq, bp, b_actq);
else
TAILQ_INSERT_TAIL(&prio->bq_write, bp, b_actq);
}
static struct buf *
bufq_prio_get(struct bufq_state *bufq, int remove)
{
struct bufq_prio *prio = bufq->bq_private;
struct buf *bp;
/*
* If no current request, get next from the lists.
*/
if (prio->bq_next == NULL) {
/*
* If at least one list is empty, select the other.
*/
if (TAILQ_FIRST(&prio->bq_read) == NULL) {
prio->bq_next = prio->bq_write_next;
prio->bq_read_burst = 0;
} else if (prio->bq_write_next == NULL) {
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
prio->bq_read_burst = 0;
} else {
/*
* Both list have requests. Select the read list up
* to PRIO_READ_BURST times, then select the write
* list PRIO_WRITE_REQ times.
*/
if (prio->bq_read_burst++ < PRIO_READ_BURST)
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
else if (prio->bq_read_burst <
PRIO_READ_BURST + PRIO_WRITE_REQ)
prio->bq_next = prio->bq_write_next;
else {
prio->bq_next = TAILQ_FIRST(&prio->bq_read);
prio->bq_read_burst = 0;
}
}
}
bp = prio->bq_next;
if (prio->bq_next != NULL && remove) {
if ((prio->bq_next->b_flags & B_READ) == B_READ)
TAILQ_REMOVE(&prio->bq_read, prio->bq_next, b_actq);
else {
TAILQ_REMOVE(&prio->bq_write, prio->bq_next, b_actq);
/*
* Advance the write pointer.
*/
prio->bq_write_next =
TAILQ_NEXT(prio->bq_write_next, b_actq);
if (prio->bq_write_next == NULL)
prio->bq_write_next =
TAILQ_FIRST(&prio->bq_write);
}
prio->bq_next = NULL;
}
return(bp);
}
/*
* Create a device buffer queue.
*/
void
bufq_alloc(struct bufq_state *bufq, int flags)
{
struct bufq_fcfs *fcfs;
struct bufq_disksort *disksort;
struct bufq_prio *prio;
bufq->bq_flags = flags;
switch (flags & BUFQ_SORT_MASK) {
case BUFQ_SORT_RAWBLOCK:
case BUFQ_SORT_CYLINDER:
break;
case 0:
if ((flags & BUFQ_METHOD_MASK) == BUFQ_FCFS)
break;
/* FALLTHROUGH */
default:
panic("bufq_alloc: sort out of range");
}
switch (flags & BUFQ_METHOD_MASK) {
case BUFQ_FCFS:
bufq->bq_get = bufq_fcfs_get;
bufq->bq_put = bufq_fcfs_put;
MALLOC(bufq->bq_private, struct bufq_fcfs *,
sizeof(struct bufq_fcfs), M_DEVBUF, M_ZERO);
fcfs = (struct bufq_fcfs *)bufq->bq_private;
TAILQ_INIT(&fcfs->bq_head);
break;
case BUFQ_DISKSORT:
bufq->bq_get = bufq_disksort_get;
bufq->bq_put = bufq_disksort_put;
MALLOC(bufq->bq_private, struct bufq_disksort *,
sizeof(struct bufq_disksort), M_DEVBUF, M_ZERO);
disksort = (struct bufq_disksort *)bufq->bq_private;
TAILQ_INIT(&disksort->bq_head);
break;
case BUFQ_READ_PRIO:
bufq->bq_get = bufq_prio_get;
bufq->bq_put = bufq_prio_put;
MALLOC(bufq->bq_private, struct bufq_prio *,
sizeof(struct bufq_prio), M_DEVBUF, M_ZERO);
prio = (struct bufq_prio *)bufq->bq_private;
TAILQ_INIT(&prio->bq_read);
TAILQ_INIT(&prio->bq_write);
break;
default:
panic("bufq_alloc: method out of range");
}
}
/*
* Destroy a device buffer queue.
*/
void
bufq_free(struct bufq_state *bufq)
{
KASSERT(bufq->bq_private != NULL);
KASSERT(BUFQ_PEEK(bufq) == NULL);
FREE(bufq->bq_private, M_DEVBUF);
bufq->bq_get = NULL;
bufq->bq_put = NULL;
}