Add an experimental Memory-Disk driver. This driver will allocate
memory with malloc(9) using a few tricks to save space on the way.
This commit is contained in:
Poul-Henning Kamp
parent
163473ebd5
commit
00a6a3c65f
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=51499
@ -124,6 +124,7 @@ dev/ida/ida.c optional ida
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dev/ida/ida_disk.c optional id
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dev/isp/isp_freebsd.c optional isp
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dev/isp/isp.c optional isp
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dev/md/md.c optional md
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dev/mii/mii.c optional miibus
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dev/mii/mii_physubr.c optional miibus
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dev/mii/ukphy.c optional miibus
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@ -35,7 +35,7 @@ blkdev name comments
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19 wcdb ATAPI CDROM client of "wd"
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20 ?? ATA disks
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21 ccd concatenated disk
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22 was:gd Geometry disk.
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22 md Memory Disk
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24 was:wstb ATAPI tape client of "wd"
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25 vinum Volume manager
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26 sw VM internal swap device
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@ -145,7 +145,7 @@ chrdev name comments
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92 bktr Bt848 video capture driver (hasty@star-gate.com)
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93 coda CODA filesystem.
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94 loran Loran-C Receiver
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95 was:gd Geometry disk
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95 md Memory Disk
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96 altq alternate queueing (including cbq, red, wfq)
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97 myx Mylex RAID controller (ulf@alameda.net)
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98 loe Loopback pseudo-ethernet (sbabkin@dcn.att.com)
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282
sys/dev/md/md.c
Normal file
282
sys/dev/md/md.c
Normal file
@ -0,0 +1,282 @@
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/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysctl.h>
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#include <sys/kernel.h>
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#include <sys/buf.h>
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#include <sys/malloc.h>
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#include <sys/conf.h>
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#include <sys/disk.h>
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#include <sys/devicestat.h>
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#include <sys/module.h>
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#include <machine/bus.h>
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#include <machine/clock.h>
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#include <machine/resource.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <vm/vm_param.h>
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#include <sys/bus.h>
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#include <isa/isareg.h>
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#include <isa/isavar.h>
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MALLOC_DEFINE(M_MD, "MD disk", "Memory Disk");
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MALLOC_DEFINE(M_MDSECT, "MD sectors", "Memory Disk Sectors");
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static int md_debug = 0;
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SYSCTL_INT(_debug, OID_AUTO, mddebug, CTLFLAG_RW, &md_debug, 0, "");
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#define CDEV_MAJOR 95
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#define BDEV_MAJOR 22
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static d_strategy_t mdstrategy;
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static d_open_t mdopen;
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static d_ioctl_t mdioctl;
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static struct cdevsw md_cdevsw = {
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/* open */ mdopen,
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/* close */ nullclose,
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/* read */ physread,
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/* write */ physwrite,
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/* ioctl */ mdioctl,
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/* stop */ nostop,
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/* reset */ noreset,
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/* devtotty */ nodevtotty,
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/* poll */ nopoll,
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/* mmap */ nommap,
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/* strategy */ mdstrategy,
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/* name */ "md",
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/* parms */ noparms,
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/* maj */ CDEV_MAJOR,
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/* dump */ nodump,
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/* psize */ nopsize,
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/* flags */ D_DISK | D_CANFREE,
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/* maxio */ 0,
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/* bmaj */ BDEV_MAJOR
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};
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static struct cdevsw mddisk_cdevsw;
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struct md_s {
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int unit;
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struct devstat stats;
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struct buf_queue_head buf_queue;
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struct disk disk;
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dev_t dev;
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unsigned nsect;
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unsigned nsecp;
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u_char **secp;
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int busy;
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};
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static int mdunits;
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static int
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mdopen(dev_t dev, int flag, int fmt, struct proc *p)
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{
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struct md_s *sc;
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struct disklabel *dl;
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if (md_debug)
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printf("mdopen(%s %x %x %p)\n",
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devtoname(dev), flag, fmt, p);
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sc = dev->si_drv1;
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dl = &sc->disk.d_label;
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bzero(dl, sizeof(*dl));
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dl->d_secsize = DEV_BSIZE;
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dl->d_nsectors = 1024;
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dl->d_ntracks = 1;
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dl->d_secpercyl = dl->d_nsectors + dl->d_ntracks;
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dl->d_secperunit = sc->nsect;
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dl->d_ncylinders = dl->d_secperunit / dl->d_secpercyl;
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return (0);
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}
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static int
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mdioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct proc *p)
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{
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if (md_debug)
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printf("mdioctl(%s %lx %p %x %p)\n",
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devtoname(dev), cmd, addr, flags, p);
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return (ENOIOCTL);
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}
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static void
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mdstrategy(struct buf *bp)
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{
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int s, i;
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struct md_s *sc;
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devstat_trans_flags dop;
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u_char *secp, **secpp, *dst;
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unsigned secno, nsec, secval, uc;
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if (md_debug > 1)
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printf("mdstrategy(%p) %s %lx, %d, %ld, %p)\n",
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bp, devtoname(bp->b_dev), bp->b_flags, bp->b_blkno,
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bp->b_bcount / DEV_BSIZE, bp->b_data);
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sc = bp->b_dev->si_drv1;
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s = splbio();
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bufqdisksort(&sc->buf_queue, bp);
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if (sc->busy) {
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splx(s);
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return;
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}
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sc->busy++;
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while (1) {
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bp = bufq_first(&sc->buf_queue);
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if (bp)
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bufq_remove(&sc->buf_queue, bp);
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splx(s);
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if (!bp)
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break;
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devstat_start_transaction(&sc->stats);
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if (bp->b_flags & B_FREEBUF)
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dop = DEVSTAT_NO_DATA;
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else if (bp->b_flags & B_READ)
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dop = DEVSTAT_READ;
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else
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dop = DEVSTAT_WRITE;
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nsec = bp->b_bcount / DEV_BSIZE;
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secno = bp->b_pblkno;
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dst = bp->b_data;
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while (nsec--) {
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if (secno < sc->nsecp) {
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secpp = &sc->secp[secno];
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if ((u_int)secpp > 255) {
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secp = *secpp;
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secval = 0;
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} else {
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secp = 0;
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secval = (u_int) secpp;
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}
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} else {
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secpp = 0;
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secp = 0;
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secval = 0;
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}
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if (bp->b_flags & B_FREEBUF) {
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if (secpp) {
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if (secp)
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FREE(secp, M_MDSECT);
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*secpp = 0;
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}
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} else if (bp->b_flags & B_READ) {
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if (secp) {
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bcopy(secp, dst, DEV_BSIZE);
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} else if (secval) {
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for (i = 0; i < DEV_BSIZE; i++)
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dst[i] = secval;
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} else {
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bzero(dst, DEV_BSIZE);
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}
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} else {
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uc = dst[0];
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for (i = 1; i < DEV_BSIZE; i++)
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if (dst[i] != uc)
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break;
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if (i == DEV_BSIZE && !uc) {
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if (secp)
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FREE(secp, M_MDSECT);
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if (secpp)
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*secpp = (u_char *)uc;
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} else {
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if (!secpp) {
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MALLOC(secpp, u_char **, (secno + nsec + 1) * sizeof(u_char *), M_MD, M_WAITOK);
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bzero(secpp, (secno + nsec + 1) * sizeof(u_char *));
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bcopy(sc->secp, secpp, sc->nsecp * sizeof(u_char *));
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FREE(sc->secp, M_MD);
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sc->secp = secpp;
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sc->nsecp = secno + nsec + 1;
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secpp = &sc->secp[secno];
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}
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if (i == DEV_BSIZE) {
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if (secp)
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FREE(secp, M_MDSECT);
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*secpp = (u_char *)uc;
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} else {
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if (!secp)
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MALLOC(secp, u_char *, DEV_BSIZE, M_MDSECT, M_WAITOK);
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bcopy(dst, secp, DEV_BSIZE);
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*secpp = secp;
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}
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}
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}
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secno++;
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dst += DEV_BSIZE;
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}
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bp->b_resid = 0;
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biodone(bp);
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devstat_end_transaction(&sc->stats, bp->b_bcount,
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DEVSTAT_TAG_NONE, dop);
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s = splbio();
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}
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sc->busy = 0;
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return;
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}
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static dev_t
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mdcreate(void)
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{
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struct md_s *sc;
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MALLOC(sc, struct md_s *,sizeof(*sc), M_MD, M_WAITOK);
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bzero(sc, sizeof(*sc));
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sc->unit = mdunits++;
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bufq_init(&sc->buf_queue);
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devstat_add_entry(&sc->stats, "md", sc->unit, DEV_BSIZE,
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DEVSTAT_NO_ORDERED_TAGS,
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DEVSTAT_TYPE_DIRECT | DEVSTAT_TYPE_IF_OTHER, 0x190);
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sc->dev = disk_create(sc->unit, &sc->disk, 0,
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&md_cdevsw, &mddisk_cdevsw);
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sc->dev->si_drv1 = sc;
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sc->nsect = 10000 * 2; /* for now */
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MALLOC(sc->secp, u_char **, sizeof(u_char *), M_MD, M_WAITOK);
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bzero(sc->secp, sizeof(u_char *));
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sc->nsecp = 1;
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return (0);
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}
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static void
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md_drvinit(void *unused)
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{
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mdcreate();
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}
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SYSINIT(ptcdev,SI_SUB_DRIVERS,SI_ORDER_MIDDLE+CDEV_MAJOR, md_drvinit,NULL)
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@ -35,7 +35,7 @@ blkdev name comments
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19 wcdb ATAPI CDROM client of "wd"
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20 ?? ATA disks
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21 ccd concatenated disk
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22 was:gd Geometry disk.
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22 md Memory Disk
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24 was:wstb ATAPI tape client of "wd"
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25 vinum Volume manager
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26 sw VM internal swap device
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@ -145,7 +145,7 @@ chrdev name comments
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92 bktr Bt848 video capture driver (hasty@star-gate.com)
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93 coda CODA filesystem.
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94 loran Loran-C Receiver
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95 was:gd Geometry disk
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95 md Memory Disk
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96 altq alternate queueing (including cbq, red, wfq)
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97 myx Mylex RAID controller (ulf@alameda.net)
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98 loe Loopback pseudo-ethernet (sbabkin@dcn.att.com)
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