1 /* 2 * Copyright (c) 1994 John S. Dyson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice immediately at the beginning of the file, without modification, 10 * this list of conditions, and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. Absolutely no warranty of function or purpose is made by the author 15 * John S. Dyson. 16 * 4. Modifications may be freely made to this file if the above conditions 17 * are met. 18 */ 19 20 #include <sys/cdefs.h> 21 __FBSDID("$FreeBSD$"); 22 23 #include <sys/param.h> 24 #include <sys/systm.h> 25 #include <sys/bio.h> 26 #include <sys/buf.h> 27 #include <sys/conf.h> 28 #include <sys/proc.h> 29 #include <sys/uio.h> 30 31 #include <vm/vm.h> 32 #include <vm/vm_extern.h> 33 34 int 35 physio(dev_t dev, struct uio *uio, int ioflag) 36 { 37 int i; 38 int error; 39 int spl; 40 caddr_t sa; 41 u_int iolen; 42 struct buf *bp; 43 44 /* We cannot trust the device driver to hold Giant for us */ 45 mtx_lock(&Giant); 46 /* Keep the process UPAGES from being swapped. XXX: why ? */ 47 PHOLD(curproc); 48 49 bp = getpbuf(NULL); 50 sa = bp->b_data; 51 error = 0; 52 53 /* XXX: sanity check */ 54 if(dev->si_iosize_max < PAGE_SIZE) { 55 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 56 devtoname(dev), dev->si_iosize_max); 57 dev->si_iosize_max = DFLTPHYS; 58 } 59 60 for (i = 0; i < uio->uio_iovcnt; i++) { 61 while (uio->uio_iov[i].iov_len) { 62 bp->b_flags = B_PHYS; 63 if (uio->uio_rw == UIO_READ) 64 bp->b_iocmd = BIO_READ; 65 else 66 bp->b_iocmd = BIO_WRITE; 67 bp->b_dev = dev; 68 bp->b_iodone = bdone; 69 bp->b_data = uio->uio_iov[i].iov_base; 70 bp->b_bcount = uio->uio_iov[i].iov_len; 71 bp->b_offset = uio->uio_offset; 72 bp->b_saveaddr = sa; 73 74 /* Don't exceed drivers iosize limit */ 75 if (bp->b_bcount > dev->si_iosize_max) 76 bp->b_bcount = dev->si_iosize_max; 77 78 /* 79 * Make sure the pbuf can map the request 80 * XXX: The pbuf has kvasize = MAXPHYS so a request 81 * XXX: larger than MAXPHYS - PAGE_SIZE must be 82 * XXX: page aligned or it will be fragmented. 83 */ 84 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 85 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 86 bp->b_bcount = bp->b_kvasize; 87 if (iolen != 0) 88 bp->b_bcount -= PAGE_SIZE; 89 } 90 bp->b_bufsize = bp->b_bcount; 91 92 bp->b_blkno = btodb(bp->b_offset); 93 94 if (uio->uio_segflg == UIO_USERSPACE) 95 if (vmapbuf(bp) < 0) { 96 error = EFAULT; 97 goto doerror; 98 } 99 100 DEV_STRATEGY(bp); 101 spl = splbio(); 102 if (uio->uio_rw == UIO_READ) 103 bwait(bp, PRIBIO, "physrd"); 104 else 105 bwait(bp, PRIBIO, "physwr"); 106 splx(spl); 107 108 if (uio->uio_segflg == UIO_USERSPACE) 109 vunmapbuf(bp); 110 iolen = bp->b_bcount - bp->b_resid; 111 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR)) 112 goto doerror; /* EOF */ 113 uio->uio_iov[i].iov_len -= iolen; 114 uio->uio_iov[i].iov_base = 115 (char *)uio->uio_iov[i].iov_base + iolen; 116 uio->uio_resid -= iolen; 117 uio->uio_offset += iolen; 118 if( bp->b_ioflags & BIO_ERROR) { 119 error = bp->b_error; 120 goto doerror; 121 } 122 } 123 } 124 doerror: 125 relpbuf(bp, NULL); 126 PRELE(curproc); 127 mtx_unlock(&Giant); 128 return (error); 129 } 130