# /* * Copyright 1973 Bell Telephone Laboratories Inc */ #include "../param.h" #include "../user.h" #include "../buf.h" #include "../conf.h" #include "../systm.h" #include "../proc.h" #include "../seg.h" char buffers[NBUF][514]; struct buf swbuf; struct { int int;}; #define PS 0177776 int tmtab; int raflag 1; bread(dev, blkno) { register struct buf *rbp; rbp = getblk(dev, blkno); if (rbp->b_flags&B_DONE) return(rbp); rbp->b_flags =| B_READ; rbp->b_wcount = -256; (*bdevsw[dev.d_major].d_strategy)(rbp); iowait(rbp); return(rbp); } breada(adev, blkno, rablkno) { register struct buf *rbp, *rabp; register int dev; dev = adev; rbp = 0; if (!incore(dev, blkno)) { rbp = getblk(dev, blkno); if ((rbp->b_flags&B_DONE) == 0) { rbp->b_flags =| B_READ; rbp->b_wcount = -256; (*bdevsw[adev.d_major].d_strategy)(rbp); } } if (rablkno && !incore(dev, rablkno) && raflag) { rabp = getblk(dev, rablkno); if (rabp->b_flags & B_DONE) brelse(rabp); else { rabp->b_flags =| B_READ|B_ASYNC; rabp->b_wcount = -256; (*bdevsw[adev.d_major].d_strategy)(rabp); } } if (rbp==0) return(bread(dev, blkno)); iowait(rbp); return(rbp); } bwrite(bp) struct buf *bp; { register struct buf *rbp; register flag; rbp = bp; flag = rbp->b_flags; rbp->b_flags =& ~(B_READ | B_DONE | B_ERROR | B_DELWRI); rbp->b_wcount = -256; (*bdevsw[rbp->b_dev.d_major].d_strategy)(rbp); if ((flag&B_ASYNC) == 0) { iowait(rbp); brelse(rbp); } else if ((flag&B_DELWRI)==0) geterror(rbp); } bdwrite(bp) struct buf *bp; { register struct buf *rbp; rbp = bp; if (bdevsw[rbp->b_dev.d_major].d_tab == &tmtab) bawrite(rbp); else { rbp->b_flags =| B_DELWRI | B_DONE; brelse(rbp); } } bawrite(bp) struct buf *bp; { register struct buf *rbp; rbp = bp; rbp->b_flags =| B_ASYNC; bwrite(rbp); } brelse(bp) struct buf *bp; { register struct buf *rbp, **backp; register int sps; rbp = bp; if (rbp->b_flags&B_WANTED) wakeup(rbp); if (bfreelist.b_flags&B_WANTED) { bfreelist.b_flags =& ~B_WANTED; wakeup(&bfreelist); } if (rbp->b_flags&B_ERROR) rbp->b_dev.d_minor = -1; /* no assoc. on error */ backp = &bfreelist.av_back; sps = PS->int; spl6(); rbp->b_flags =& ~(B_WANTED|B_BUSY|B_ASYNC); (*backp)->av_forw = rbp; rbp->av_back = *backp; *backp = rbp; rbp->av_forw = &bfreelist; PS->int = sps; } incore(adev, blkno) { register int dev; register struct buf *bp; register struct devtab *dp; dev = adev; dp = bdevsw[adev.d_major].d_tab; for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) if (bp->b_blkno==blkno && bp->b_dev==dev) return(bp); return(0); } getblk(dev, blkno) { register struct buf *bp; register struct devtab *dp; extern lbolt; if(dev.d_major >= nblkdev) panic("blkdev"); loop: if (dev < 0) dp = &bfreelist; else { dp = bdevsw[dev.d_major].d_tab; for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) { if (bp->b_blkno!=blkno || bp->b_dev!=dev) continue; spl6(); if (bp->b_flags&B_BUSY) { bp->b_flags =| B_WANTED; sleep(bp, PRIBIO); spl0(); goto loop; } spl0(); notavail(bp); return(bp); } } spl6(); if (bfreelist.av_forw == &bfreelist) { bfreelist.b_flags =| B_WANTED; sleep(&bfreelist, PRIBIO); spl0(); goto loop; } spl0(); notavail(bp = bfreelist.av_forw); if (bp->b_flags & B_DELWRI) { bp->b_flags =| B_ASYNC; bwrite(bp); goto loop; } bp->b_flags = B_BUSY | B_RELOC; bp->b_back->b_forw = bp->b_forw; bp->b_forw->b_back = bp->b_back; bp->b_forw = dp->b_forw; bp->b_back = dp; dp->b_forw->b_back = bp; dp->b_forw = bp; bp->b_dev = dev; bp->b_blkno = blkno; return(bp); } iowait(bp) struct buf *bp; { register struct buf *rbp; rbp = bp; spl6(); while ((rbp->b_flags&B_DONE)==0) sleep(rbp, PRIBIO); spl0(); geterror(rbp); } notavail(bp) struct buf *bp; { register struct buf *rbp; register int sps; rbp = bp; sps = PS->int; spl6(); rbp->av_back->av_forw = rbp->av_forw; rbp->av_forw->av_back = rbp->av_back; rbp->b_flags =| B_BUSY; PS->int = sps; } iodone(bp) struct buf *bp; { register struct buf *rbp; rbp = bp; rbp->b_flags =| B_DONE; if (rbp->b_flags&B_ASYNC) brelse(rbp); else { rbp->b_flags =& ~B_WANTED; wakeup(rbp); } } clrbuf(bp) int *bp; { register *p; register c; p = bp->b_addr; c = 256; do *p++ = 0; while (--c); } binit() { register struct buf *bp; register struct devtab *dp; register int i; struct bdevsw *bdp; bfreelist.b_forw = bfreelist.b_back = bfreelist.av_forw = bfreelist.av_back = &bfreelist; for (i=0; i<NBUF; i++) { bp = &buf[i]; bp->b_dev = -1; bp->b_addr = buffers[i]; bp->b_back = &bfreelist; bp->b_forw = bfreelist.b_forw; bfreelist.b_forw->b_back = bp; bfreelist.b_forw = bp; bp->b_flags = B_BUSY; brelse(bp); } i = 0; for (bdp = bdevsw; bdp->d_open; bdp++) { dp = bdp->d_tab; dp->b_forw = dp; dp->b_back = dp; i++; } nblkdev = i; } /* * Device start routine for disks */ #define IENABLE 0100 #define WCOM 02 #define RCOM 04 #define GO 01 devstart(bp, devloc, devblk, hbcom) struct buf *bp; int *devloc; { register int *dp; register struct buf *rbp; register int com; dp = devloc; rbp = bp; *dp = devblk; /* block address */ *--dp = rbp->b_addr; /* buffer address */ *--dp = rbp->b_wcount; /* word count */ com = (hbcom<<8) | IENABLE | GO | rbp->b_flags&B_XMEM; if (rbp->b_flags&B_READ) /* command + x-mem */ com =| RCOM; else com =| WCOM; *--dp = com; } /* * swap I/O */ swap(blkno, coreaddr, count, rdflg) { register int *fp; fp = &swbuf.b_flags; spl6(); while (*fp&B_BUSY) { *fp =| B_WANTED; sleep(fp, PSWP); } *fp = B_BUSY | rdflg | (coreaddr>>6)&B_XMEM; swbuf.b_dev = swapdev; swbuf.b_wcount = - (count<<5); /* 32 w/block */ swbuf.b_blkno = blkno; swbuf.b_addr = coreaddr<<6; /* 64 b/block */ (*bdevsw[swapdev>>8].d_strategy)(&swbuf); spl6(); while((*fp&B_DONE)==0) sleep(fp, PSWP); if (*fp&B_WANTED) wakeup(fp); spl0(); *fp =& ~(B_BUSY|B_WANTED); return(*fp&B_ERROR); } /* * make sure all write-behind blocks * on dev (or NODEV for all) * are flushed out. */ bflush(dev) { register struct buf *bp; loop: spl6(); for (bp = bfreelist.av_forw; bp != &bfreelist; bp = bp->av_forw) { if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) { bp->b_flags =| B_ASYNC; notavail(bp); bwrite(bp); goto loop; } } spl0(); } physio(strat, abp, dev, rw) struct buf *abp; int (*strat)(); { register struct buf *bp; register char *base; register int nb; int ts; bp = abp; base = u.u_base; if (base&01 || u.u_count&01 || base>=base+u.u_count) goto bad; ts = (u.u_tsize+127) & ~0177; nb = (base>>6) & 01777; if (nb < ts) goto bad; if ((((base+u.u_count)>>6)&01777) >= ts+u.u_dsize && nb < 1024-u.u_ssize) goto bad; spl6(); while (bp->b_flags&B_BUSY) { bp->b_flags =| B_WANTED; sleep(bp, PRIBIO); } bp->b_flags = B_BUSY | rw; bp->b_dev = dev; bp->b_addr = base&077; base = UISA->r[nb>>7] + (nb&0177); bp->b_flags =| (base>>6) & B_XMEM; bp->b_blkno = lshift(u.u_offset, -9); bp->b_addr =+ base<<6; bp->b_wcount = -((u.u_count>>1) & 077777); bp->b_error = 0; u.u_procp->p_flag =| SLOCK; (*strat)(bp); spl6(); while ((bp->b_flags&B_DONE) == 0) sleep(bp, PRIBIO); u.u_procp->p_flag =& ~SLOCK; if (bp->b_flags&B_WANTED) wakeup(bp); spl0(); bp->b_flags =& ~(B_BUSY|B_WANTED); u.u_count = (-bp->b_resid)<<1; geterror(bp); return; bad: u.u_error = EFAULT; } geterror(abp) struct buf *abp; { register struct buf *bp; bp = abp; if (bp->b_flags&B_ERROR) if ((u.u_error = bp->b_error)==0) u.u_error = EIO; }