diff options
Diffstat (limited to 'sys/kern/kern_physio.c')
| -rw-r--r-- | sys/kern/kern_physio.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c new file mode 100644 index 0000000..e29d0b9 --- /dev/null +++ b/sys/kern/kern_physio.c @@ -0,0 +1,189 @@ +/* + * Copyright (c) 1994 John S. Dyson + * All rights reserved. + * + * 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 immediately at the beginning of the file, without modification, + * 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. Absolutely no warranty of function or purpose is made by the author + * John S. Dyson. + * 4. Modifications may be freely made to this file if the above conditions + * are met. + * + * $Id: kern_physio.c,v 1.6 1994/08/08 13:53:55 davidg Exp $ + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/buf.h> +#include <sys/conf.h> +#include <sys/proc.h> +#include <vm/vm.h> + +static void physwakeup(); + +int +physio(strategy, bp, dev, rw, minp, uio) + int (*strategy)(); + struct buf *bp; + dev_t dev; + int rw; + u_int (*minp)(); + struct uio *uio; +{ + int i; + int bufflags = rw?B_READ:0; + int error; + int spl; + caddr_t sa; + int bp_alloc = (bp == 0); + struct buf *bpa; + +/* + * keep the process from being swapped + */ + curproc->p_flag |= P_PHYSIO; + + /* create and build a buffer header for a transfer */ + bpa = (struct buf *)getpbuf(); + if (!bp_alloc) { + spl = splbio(); + while (bp->b_flags & B_BUSY) { + bp->b_flags |= B_WANTED; + tsleep((caddr_t)bp, PRIBIO, "physbw", 0); + } + bp->b_flags |= B_BUSY; + splx(spl); + } else { + bp = bpa; + } + + /* + * get a copy of the kva from the physical buffer + */ + sa = bpa->b_data; + bp->b_proc = curproc; + bp->b_dev = dev; + error = bp->b_error = 0; + + for(i=0;i<uio->uio_iovcnt;i++) { + while( uio->uio_iov[i].iov_len) { + vm_offset_t v, lastv, pa; + caddr_t adr; + + bp->b_bcount = uio->uio_iov[i].iov_len; + bp->b_bcount = minp( bp); + if( minp != minphys) + bp->b_bcount = minphys( bp); + bp->b_bufsize = bp->b_bcount; + bp->b_flags = B_BUSY | B_PHYS | B_CALL | bufflags; + bp->b_iodone = physwakeup; + bp->b_data = uio->uio_iov[i].iov_base; + /* + * pass in the kva from the physical buffer + * for the temporary kernel mapping. + */ + bp->b_saveaddr = sa; + bp->b_blkno = btodb(uio->uio_offset); + + + if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) { + error = EFAULT; + goto doerror; + } + if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) { + error = EFAULT; + goto doerror; + } + + vmapbuf(bp); + + /* perform transfer */ + (*strategy)(bp); + + spl = splbio(); + while ((bp->b_flags & B_DONE) == 0) + tsleep((caddr_t)bp, PRIBIO, "physstr", 0); + splx(spl); + + vunmapbuf(bp); + + /* + * update the uio data + */ + { + int iolen = bp->b_bcount - bp->b_resid; + + if (iolen == 0 && !(bp->b_flags & B_ERROR)) + goto doerror; /* EOF */ + uio->uio_iov[i].iov_len -= iolen; + uio->uio_iov[i].iov_base += iolen; + uio->uio_resid -= iolen; + uio->uio_offset += iolen; + } + + /* + * check for an error + */ + if( bp->b_flags & B_ERROR) { + error = bp->b_error; + goto doerror; + } + } + } + + +doerror: + relpbuf(bpa); + if (!bp_alloc) { + bp->b_flags &= ~(B_BUSY|B_PHYS); + if( bp->b_flags & B_WANTED) { + bp->b_flags &= ~B_WANTED; + wakeup((caddr_t)bp); + } + } +/* + * allow the process to be swapped + */ + curproc->p_flag &= ~P_PHYSIO; + + return (error); +} + +u_int +minphys(struct buf *bp) +{ + + if( bp->b_bcount > MAXBSIZE) { + bp->b_bcount = MAXBSIZE; + } + return bp->b_bcount; +} + +int +rawread(dev_t dev, struct uio *uio) +{ + return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, + dev, 1, minphys, uio)); +} + +int +rawwrite(dev_t dev, struct uio *uio) +{ + return (physio(cdevsw[major(dev)].d_strategy, (struct buf *)NULL, + dev, 0, minphys, uio)); +} + +static void +physwakeup(bp) + struct buf *bp; +{ + wakeup((caddr_t) bp); + bp->b_flags &= ~B_CALL; +} |
