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(struct cdev *dev, struct uio *uio, int ioflag) 36 { 37 int i; 38 int error; 39 caddr_t sa; 40 u_int iolen; 41 struct buf *bp; 42 43 /* Keep the process UPAGES from being swapped. XXX: why ? */ 44 PHOLD(curproc); 45 46 bp = getpbuf(NULL); 47 sa = bp->b_data; 48 error = 0; 49 50 /* XXX: sanity check */ 51 if(dev->si_iosize_max < PAGE_SIZE) { 52 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n", 53 devtoname(dev), dev->si_iosize_max); 54 dev->si_iosize_max = DFLTPHYS; 55 } 56 57 for (i = 0; i < uio->uio_iovcnt; i++) { 58 while (uio->uio_iov[i].iov_len) { 59 bp->b_flags = 0; 60 if (uio->uio_rw == UIO_READ) 61 bp->b_iocmd = BIO_READ; 62 else 63 bp->b_iocmd = BIO_WRITE; 64 bp->b_dev = dev; 65 bp->b_iodone = bdone; 66 bp->b_data = uio->uio_iov[i].iov_base; 67 bp->b_bcount = uio->uio_iov[i].iov_len; 68 bp->b_offset = uio->uio_offset; 69 bp->b_iooffset = uio->uio_offset; 70 bp->b_saveaddr = sa; 71 72 /* Don't exceed drivers iosize limit */ 73 if (bp->b_bcount > dev->si_iosize_max) 74 bp->b_bcount = dev->si_iosize_max; 75 76 /* 77 * Make sure the pbuf can map the request 78 * XXX: The pbuf has kvasize = MAXPHYS so a request 79 * XXX: larger than MAXPHYS - PAGE_SIZE must be 80 * XXX: page aligned or it will be fragmented. 81 */ 82 iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK; 83 if ((bp->b_bcount + iolen) > bp->b_kvasize) { 84 bp->b_bcount = bp->b_kvasize; 85 if (iolen != 0) 86 bp->b_bcount -= PAGE_SIZE; 87 } 88 bp->b_bufsize = bp->b_bcount; 89 90 bp->b_blkno = btodb(bp->b_offset); 91 92 if (uio->uio_segflg == UIO_USERSPACE) 93 if (vmapbuf(bp) < 0) { 94 error = EFAULT; 95 goto doerror; 96 } 97 98 DEV_STRATEGY(bp); 99 if (uio->uio_rw == UIO_READ) 100 bwait(bp, PRIBIO, "physrd"); 101 else 102 bwait(bp, PRIBIO, "physwr"); 103 104 if (uio->uio_segflg == UIO_USERSPACE) 105 vunmapbuf(bp); 106 iolen = bp->b_bcount - bp->b_resid; 107 if (iolen == 0 && !(bp->b_ioflags & BIO_ERROR)) 108 goto doerror; /* EOF */ 109 uio->uio_iov[i].iov_len -= iolen; 110 uio->uio_iov[i].iov_base = 111 (char *)uio->uio_iov[i].iov_base + iolen; 112 uio->uio_resid -= iolen; 113 uio->uio_offset += iolen; 114 if( bp->b_ioflags & BIO_ERROR) { 115 error = bp->b_error; 116 goto doerror; 117 } 118 } 119 } 120 doerror: 121 relpbuf(bp, NULL); 122 PRELE(curproc); 123 return (error); 124 } 125