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/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/racct.h>
#include <sys/rwlock.h>
#include <sys/uio.h>
#include <geom/geom.h>
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_page.h>
#include <vm/vm_pager.h>
#include <vm/vm_extern.h>
#include <vm/vm_map.h>
int
physio(struct cdev *dev, struct uio *uio, int ioflag)
{
struct cdevsw *csw;
struct buf *pbuf;
struct bio *bp;
struct vm_page **pages;
char *base, *sa;
u_int iolen, poff;
int error, i, npages, maxpages;
vm_prot_t prot;
csw = dev->si_devsw;
npages = 0;
sa = NULL;
/* check if character device is being destroyed */
if (csw == NULL)
return (ENXIO);
/* 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;
}
/*
* If the driver does not want I/O to be split, that means that we
* need to reject any requests that will not fit into one buffer.
*/
if (dev->si_flags & SI_NOSPLIT &&
(uio->uio_resid > dev->si_iosize_max || uio->uio_resid > maxphys ||
uio->uio_iovcnt > 1)) {
/*
* Tell the user why his I/O was rejected.
*/
if (uio->uio_resid > dev->si_iosize_max)
uprintf("%s: request size=%zd > si_iosize_max=%d; "
"cannot split request\n", devtoname(dev),
uio->uio_resid, dev->si_iosize_max);
if (uio->uio_resid > maxphys)
uprintf("%s: request size=%zd > maxphys=%lu; "
"cannot split request\n", devtoname(dev),
uio->uio_resid, maxphys);
if (uio->uio_iovcnt > 1)
uprintf("%s: request vectors=%d > 1; "
"cannot split request\n", devtoname(dev),
uio->uio_iovcnt);
return (EFBIG);
}
/*
* Keep the process UPAGES from being swapped. Processes swapped
* out while holding pbufs, used by swapper, may lead to deadlock.
*/
PHOLD(curproc);
bp = g_alloc_bio();
if (uio->uio_segflg != UIO_USERSPACE) {
pbuf = NULL;
pages = NULL;
} else if ((dev->si_flags & SI_UNMAPPED) && unmapped_buf_allowed) {
pbuf = NULL;
maxpages = btoc(MIN(uio->uio_resid, maxphys)) + 1;
pages = malloc(sizeof(*pages) * maxpages, M_DEVBUF, M_WAITOK);
} else {
pbuf = uma_zalloc(pbuf_zone, M_WAITOK);
MPASS((pbuf->b_flags & B_MAXPHYS) != 0);
sa = pbuf->b_data;
maxpages = PBUF_PAGES;
pages = pbuf->b_pages;
}
prot = VM_PROT_READ;
if (uio->uio_rw == UIO_READ)
prot |= VM_PROT_WRITE; /* Less backwards than it looks */
error = 0;
for (i = 0; i < uio->uio_iovcnt; i++) {
#ifdef RACCT
if (racct_enable) {
PROC_LOCK(curproc);
if (uio->uio_rw == UIO_READ) {
racct_add_force(curproc, RACCT_READBPS,
uio->uio_iov[i].iov_len);
racct_add_force(curproc, RACCT_READIOPS, 1);
} else {
racct_add_force(curproc, RACCT_WRITEBPS,
uio->uio_iov[i].iov_len);
racct_add_force(curproc, RACCT_WRITEIOPS, 1);
}
PROC_UNLOCK(curproc);
}
#endif /* RACCT */
while (uio->uio_iov[i].iov_len) {
g_reset_bio(bp);
if (uio->uio_rw == UIO_READ) {
bp->bio_cmd = BIO_READ;
curthread->td_ru.ru_inblock++;
} else {
bp->bio_cmd = BIO_WRITE;
curthread->td_ru.ru_oublock++;
}
bp->bio_offset = uio->uio_offset;
base = uio->uio_iov[i].iov_base;
bp->bio_length = uio->uio_iov[i].iov_len;
if (bp->bio_length > dev->si_iosize_max)
bp->bio_length = dev->si_iosize_max;
if (bp->bio_length > maxphys)
bp->bio_length = maxphys;
bp->bio_bcount = bp->bio_length;
bp->bio_dev = dev;
if (pages) {
if ((npages = vm_fault_quick_hold_pages(
&curproc->p_vmspace->vm_map,
(vm_offset_t)base, bp->bio_length,
prot, pages, maxpages)) < 0) {
error = EFAULT;
goto doerror;
}
poff = (vm_offset_t)base & PAGE_MASK;
if (pbuf && sa) {
pmap_qenter((vm_offset_t)sa,
pages, npages);
bp->bio_data = sa + poff;
} else {
bp->bio_ma = pages;
bp->bio_ma_n = npages;
bp->bio_ma_offset = poff;
bp->bio_data = unmapped_buf;
bp->bio_flags |= BIO_UNMAPPED;
}
} else
bp->bio_data = base;
csw->d_strategy(bp);
if (uio->uio_rw == UIO_READ)
biowait(bp, "physrd");
else
biowait(bp, "physwr");
if (pages) {
if (pbuf)
pmap_qremove((vm_offset_t)sa, npages);
vm_page_unhold_pages(pages, npages);
}
iolen = bp->bio_length - bp->bio_resid;
if (iolen == 0 && !(bp->bio_flags & BIO_ERROR))
goto doerror; /* EOF */
uio->uio_iov[i].iov_len -= iolen;
uio->uio_iov[i].iov_base =
(char *)uio->uio_iov[i].iov_base + iolen;
uio->uio_resid -= iolen;
uio->uio_offset += iolen;
if (bp->bio_flags & BIO_ERROR) {
error = bp->bio_error;
goto doerror;
}
}
}
doerror:
if (pbuf)
uma_zfree(pbuf_zone, pbuf);
else if (pages)
free(pages, M_DEVBUF);
g_destroy_bio(bp);
PRELE(curproc);
return (error);
}
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