freebsd-skq/sys/kern/kern_physio.c
Kenneth D. Merry ce625ec719 Change the way that unmapped I/O capability is advertised.
The previous method was to set the D_UNMAPPED_IO flag in the cdevsw
for the driver.  The problem with this is that in many cases (e.g.
sa(4)) there may be some instances of the driver that can handle
unmapped I/O and some that can't.  The isp(4) driver can handle
unmapped I/O, but the esp(4) driver currently cannot.  The cdevsw
is shared among all driver instances.

So instead of setting a flag on the cdevsw, set a flag on the cdev.
This allows drivers to indicate support for unmapped I/O on a
per-instance basis.

sys/conf.h:	Remove the D_UNMAPPED_IO cdevsw flag and replace it
		with an SI_UNMAPPED cdev flag.

kern_physio.c:	Look at the cdev SI_UNMAPPED flag to determine
		whether or not a particular driver can handle
		unmapped I/O.

geom_dev.c:	Set the SI_UNMAPPED flag for all GEOM cdevs.
		Since GEOM will create a temporary mapping when
		needed, setting SI_UNMAPPED unconditionally will
		work.

		Remove the D_UNMAPPED_IO flag.

nvme_ns.c:	Set the SI_UNMAPPED flag on cdevs created here
		if NVME_UNMAPPED_BIO_SUPPORT is enabled.

vfs_aio.c:	In aio_qphysio(), check the SI_UNMAPPED flag on a
		cdev instead of the D_UNMAPPED_IO flag on the cdevsw.

sys/param.h:	Bump __FreeBSD_version to 1000045 for the switch from
		setting the D_UNMAPPED_IO flag in the cdevsw to setting
		SI_UNMAPPED in the cdev.

Reviewed by:	kib, jimharris
MFC after:	1 week
Sponsored by:	Spectra Logic
2013-08-15 22:52:39 +00:00

133 lines
3.5 KiB
C

/*-
* 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/proc.h>
#include <sys/uio.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
int
physio(struct cdev *dev, struct uio *uio, int ioflag)
{
struct buf *bp;
struct cdevsw *csw;
caddr_t sa;
u_int iolen;
int error, i, mapped;
/* Keep the process UPAGES from being swapped. XXX: why ? */
PHOLD(curproc);
bp = getpbuf(NULL);
sa = bp->b_data;
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) {
bp->b_flags = 0;
if (uio->uio_rw == UIO_READ) {
bp->b_iocmd = BIO_READ;
curthread->td_ru.ru_inblock++;
} else {
bp->b_iocmd = BIO_WRITE;
curthread->td_ru.ru_oublock++;
}
bp->b_iodone = bdone;
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_iooffset = 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;
bp->b_blkno = btodb(bp->b_offset);
csw = dev->si_devsw;
if (uio->uio_segflg == UIO_USERSPACE) {
if (dev->si_flags & SI_UNMAPPED)
mapped = 0;
else
mapped = 1;
if (vmapbuf(bp, mapped) < 0) {
error = EFAULT;
goto doerror;
}
}
dev_strategy_csw(dev, csw, bp);
if (uio->uio_rw == UIO_READ)
bwait(bp, PRIBIO, "physrd");
else
bwait(bp, PRIBIO, "physwr");
if (uio->uio_segflg == UIO_USERSPACE)
vunmapbuf(bp);
iolen = bp->b_bcount - bp->b_resid;
if (iolen == 0 && !(bp->b_ioflags & 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->b_ioflags & BIO_ERROR) {
error = bp->b_error;
goto doerror;
}
}
}
doerror:
relpbuf(bp, NULL);
PRELE(curproc);
return (error);
}