diff options
Diffstat (limited to 'sys/kern/kern_physio.c')
| -rw-r--r-- | sys/kern/kern_physio.c | 137 |
1 files changed, 137 insertions, 0 deletions
diff --git a/sys/kern/kern_physio.c b/sys/kern/kern_physio.c new file mode 100644 index 0000000..128283f --- /dev/null +++ b/sys/kern/kern_physio.c @@ -0,0 +1,137 @@ +/* + * 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. + * + * $FreeBSD$ + */ + +#include <sys/param.h> +#include <sys/systm.h> +#include <sys/buf.h> +#include <sys/conf.h> +#include <sys/proc.h> +#include <sys/uio.h> + +#include <vm/vm.h> +#include <vm/vm_extern.h> + +static void +physwakeup(struct buf *bp) +{ + wakeup((caddr_t) bp); + bp->b_flags &= ~B_CALL; +} + +int +physio(dev_t dev, struct uio *uio, int ioflag) +{ + int i; + int error; + int spl; + caddr_t sa; + off_t blockno; + u_int iolen; + struct buf *bp; + + /* Keep the process UPAGES from being swapped. XXX: why ? */ + PHOLD(curproc); + + bp = getpbuf(NULL); + sa = bp->b_data; + error = bp->b_error = 0; + + /* XXX: sanity check */ + if(dev->si_iosize_max < PAGE_SIZE) { + printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", + devtoname(dev), dev->si_iosize_max); + dev->si_iosize_max = DFLTPHYS; + } + + for (i = 0; i < uio->uio_iovcnt; i++) { + while (uio->uio_iov[i].iov_len) { + if (uio->uio_rw == UIO_READ) + bp->b_flags = B_PHYS | B_CALL | B_READ; + else + bp->b_flags = B_PHYS | B_CALL | B_WRITE; + bp->b_dev = dev; + bp->b_iodone = physwakeup; + bp->b_data = uio->uio_iov[i].iov_base; + bp->b_bcount = uio->uio_iov[i].iov_len; + bp->b_offset = uio->uio_offset; + bp->b_saveaddr = sa; + + /* Don't exceed drivers iosize limit */ + if (bp->b_bcount > dev->si_iosize_max) + bp->b_bcount = dev->si_iosize_max; + + /* + * Make sure the pbuf can map the request + * XXX: The pbuf has kvasize = MAXPHYS so a request + * XXX: larger than MAXPHYS - PAGE_SIZE must be + * XXX: page aligned or it will be fragmented. + */ + iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; + if ((bp->b_bcount + iolen) > bp->b_kvasize) { + bp->b_bcount = bp->b_kvasize; + if (iolen != 0) + bp->b_bcount -= PAGE_SIZE; + } + bp->b_bufsize = bp->b_bcount; + + blockno = bp->b_offset >> DEV_BSHIFT; + if ((daddr_t)blockno != blockno) { + error = EINVAL; /* blockno overflow */ + goto doerror; + } + bp->b_blkno = blockno; + + if (uio->uio_segflg == UIO_USERSPACE) { + if (!useracc(bp->b_data, bp->b_bufsize, + bp->b_flags & B_READ ? + VM_PROT_WRITE : VM_PROT_READ)) { + error = EFAULT; + goto doerror; + } + vmapbuf(bp); + } + + BUF_STRATEGY(bp, 0); + spl = splbio(); + while ((bp->b_flags & B_DONE) == 0) + tsleep((caddr_t)bp, PRIBIO, "physstr", 0); + splx(spl); + + if (uio->uio_segflg == UIO_USERSPACE) + vunmapbuf(bp); + 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; + if( bp->b_flags & B_ERROR) { + error = bp->b_error; + goto doerror; + } + } + } +doerror: + relpbuf(bp, NULL); + PRELE(curproc); + return (error); +} |
