2 * SPDX-License-Identifier: BSD-4-Clause
4 * Copyright (c) 1994 John S. Dyson
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice immediately at the beginning of the file, without modification,
12 * this list of conditions, and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Absolutely no warranty of function or purpose is made by the author
18 * 4. Modifications may be freely made to this file if the above conditions
22 #include <sys/cdefs.h>
23 __FBSDID("$FreeBSD$");
25 #include <sys/param.h>
26 #include <sys/systm.h>
30 #include <sys/malloc.h>
32 #include <sys/racct.h>
34 #include <geom/geom.h>
37 #include <vm/vm_page.h>
38 #include <vm/vm_extern.h>
39 #include <vm/vm_map.h>
42 physio(struct cdev *dev, struct uio *uio, int ioflag)
47 struct vm_page **pages;
50 int error, i, npages, maxpages;
54 /* check if character device is being destroyed */
58 /* XXX: sanity check */
59 if(dev->si_iosize_max < PAGE_SIZE) {
60 printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
61 devtoname(dev), dev->si_iosize_max);
62 dev->si_iosize_max = DFLTPHYS;
66 * If the driver does not want I/O to be split, that means that we
67 * need to reject any requests that will not fit into one buffer.
69 if (dev->si_flags & SI_NOSPLIT &&
70 (uio->uio_resid > dev->si_iosize_max || uio->uio_resid > MAXPHYS ||
71 uio->uio_iovcnt > 1)) {
73 * Tell the user why his I/O was rejected.
75 if (uio->uio_resid > dev->si_iosize_max)
76 uprintf("%s: request size=%zd > si_iosize_max=%d; "
77 "cannot split request\n", devtoname(dev),
78 uio->uio_resid, dev->si_iosize_max);
79 if (uio->uio_resid > MAXPHYS)
80 uprintf("%s: request size=%zd > MAXPHYS=%d; "
81 "cannot split request\n", devtoname(dev),
82 uio->uio_resid, MAXPHYS);
83 if (uio->uio_iovcnt > 1)
84 uprintf("%s: request vectors=%d > 1; "
85 "cannot split request\n", devtoname(dev),
91 * Keep the process UPAGES from being swapped. Processes swapped
92 * out while holding pbufs, used by swapper, may lead to deadlock.
97 if (uio->uio_segflg != UIO_USERSPACE) {
100 } else if ((dev->si_flags & SI_UNMAPPED) && unmapped_buf_allowed) {
102 maxpages = btoc(MIN(uio->uio_resid, MAXPHYS)) + 1;
103 pages = malloc(sizeof(*pages) * maxpages, M_DEVBUF, M_WAITOK);
105 pbuf = getpbuf(NULL);
107 maxpages = btoc(MAXPHYS);
108 pages = pbuf->b_pages;
111 if (uio->uio_rw == UIO_READ)
112 prot |= VM_PROT_WRITE; /* Less backwards than it looks */
114 for (i = 0; i < uio->uio_iovcnt; i++) {
118 if (uio->uio_rw == UIO_READ) {
119 racct_add_force(curproc, RACCT_READBPS,
120 uio->uio_iov[i].iov_len);
121 racct_add_force(curproc, RACCT_READIOPS, 1);
123 racct_add_force(curproc, RACCT_WRITEBPS,
124 uio->uio_iov[i].iov_len);
125 racct_add_force(curproc, RACCT_WRITEIOPS, 1);
127 PROC_UNLOCK(curproc);
131 while (uio->uio_iov[i].iov_len) {
133 if (uio->uio_rw == UIO_READ) {
134 bp->bio_cmd = BIO_READ;
135 curthread->td_ru.ru_inblock++;
137 bp->bio_cmd = BIO_WRITE;
138 curthread->td_ru.ru_oublock++;
140 bp->bio_offset = uio->uio_offset;
141 bp->bio_data = uio->uio_iov[i].iov_base;
142 bp->bio_length = uio->uio_iov[i].iov_len;
143 if (bp->bio_length > dev->si_iosize_max)
144 bp->bio_length = dev->si_iosize_max;
145 if (bp->bio_length > MAXPHYS)
146 bp->bio_length = MAXPHYS;
149 * Make sure the pbuf can map the request.
150 * The pbuf has kvasize = MAXPHYS, so a request
151 * larger than MAXPHYS - PAGE_SIZE must be
152 * page aligned or it will be fragmented.
154 poff = (vm_offset_t)bp->bio_data & PAGE_MASK;
155 if (pbuf && bp->bio_length + poff > pbuf->b_kvasize) {
156 if (dev->si_flags & SI_NOSPLIT) {
157 uprintf("%s: request ptr %p is not "
158 "on a page boundary; cannot split "
159 "request\n", devtoname(dev),
164 bp->bio_length = pbuf->b_kvasize;
166 bp->bio_length -= PAGE_SIZE;
169 bp->bio_bcount = bp->bio_length;
173 if ((npages = vm_fault_quick_hold_pages(
174 &curproc->p_vmspace->vm_map,
175 (vm_offset_t)bp->bio_data, bp->bio_length,
176 prot, pages, maxpages)) < 0) {
181 pmap_qenter((vm_offset_t)sa,
183 bp->bio_data = sa + poff;
186 bp->bio_ma_n = npages;
187 bp->bio_ma_offset = poff;
188 bp->bio_data = unmapped_buf;
189 bp->bio_flags |= BIO_UNMAPPED;
194 if (uio->uio_rw == UIO_READ)
195 biowait(bp, "physrd");
197 biowait(bp, "physwr");
201 pmap_qremove((vm_offset_t)sa, npages);
202 vm_page_unhold_pages(pages, npages);
205 iolen = bp->bio_length - bp->bio_resid;
206 if (iolen == 0 && !(bp->bio_flags & BIO_ERROR))
207 goto doerror; /* EOF */
208 uio->uio_iov[i].iov_len -= iolen;
209 uio->uio_iov[i].iov_base =
210 (char *)uio->uio_iov[i].iov_base + iolen;
211 uio->uio_resid -= iolen;
212 uio->uio_offset += iolen;
213 if (bp->bio_flags & BIO_ERROR) {
214 error = bp->bio_error;
223 free(pages, M_DEVBUF);