Give physio a makeover.
- Let physio take read/write compatible args and have it use uio->uio_rw to determine the direction. - physread/physwrite are now #defines for physio - Remove the inversly named minphys(), dev->si_iosize_max takes over. - Physio() always uses pbufs. - Fix the check for non page-aligned transfers, now only unaligned transfers larger than (MAXPHYS - PAGE_SIZE) get fragmented (only interesting for tapes using max blocksize). - General wash-and-clean of code. Constructive input from: bde
This commit is contained in:
Poul-Henning Kamp
parent
f63b242474
commit
7179e74f18
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=52066
@ -29,175 +29,108 @@
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#include <vm/vm.h>
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#include <vm/vm_extern.h>
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static void physwakeup __P((struct buf *bp));
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int
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physread(dev_t dev, struct uio *uio, int ioflag)
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static void
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physwakeup(struct buf *bp)
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{
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return(physio(NULL, dev, 1, minphys, uio));
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wakeup((caddr_t) bp);
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bp->b_flags &= ~B_CALL;
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}
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int
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physwrite(dev_t dev, struct uio *uio, int ioflag)
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{
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return(physio(NULL, dev, 0, minphys, uio));
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}
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int
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physio(bp, dev, rw, minp, uio)
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struct buf *bp;
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dev_t dev;
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int rw;
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u_int (*minp) __P((struct buf *bp));
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struct uio *uio;
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physio(dev_t dev, struct uio *uio, int ioflag)
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{
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int i;
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int bufflags = rw?B_READ:0;
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int error;
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int spl;
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caddr_t sa;
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off_t blockno;
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int bp_alloc = (bp == 0);
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struct buf *bpa;
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u_int iolen;
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struct buf *bp;
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/*
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* Keep the process UPAGES from being swapped. (XXX for performance?)
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*/
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/* Keep the process UPAGES from being swapped. XXX: why ? */
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PHOLD(curproc);
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/* create and build a buffer header for a transfer */
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bpa = getpbuf(NULL);
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if (!bp_alloc)
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BUF_LOCK(bp, LK_EXCLUSIVE);
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else
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bp = bpa;
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/*
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* get a copy of the kva from the physical buffer
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*/
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sa = bpa->b_data;
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bp = getpbuf(NULL);
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sa = bp->b_data;
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error = bp->b_error = 0;
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/* XXX: sanity check */
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if(dev->si_iosize_max < PAGE_SIZE) {
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printf("WARNING: %s si_iosize_max=%d, using DFLTPHYS.\n",
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devtoname(dev), dev->si_iosize_max);
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dev->si_iosize_max = DFLTPHYS;
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}
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for (i = 0; i < uio->uio_iovcnt; i++) {
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while (uio->uio_iov[i].iov_len) {
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if (uio->uio_rw == UIO_READ)
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bp->b_flags = B_PHYS | B_CALL | B_READ;
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else
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bp->b_flags = B_PHYS | B_CALL | B_WRITE;
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bp->b_dev = dev;
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bp->b_bcount = uio->uio_iov[i].iov_len;
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bp->b_flags = B_PHYS | B_CALL | bufflags;
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bp->b_iodone = physwakeup;
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bp->b_data = uio->uio_iov[i].iov_base;
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bp->b_bcount = minp( bp);
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if( minp != minphys)
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bp->b_bcount = minphys( bp);
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bp->b_bufsize = bp->b_bcount;
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/*
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* pass in the kva from the physical buffer
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* for the temporary kernel mapping.
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*/
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bp->b_bcount = uio->uio_iov[i].iov_len;
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bp->b_offset = uio->uio_offset;
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bp->b_saveaddr = sa;
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blockno = uio->uio_offset >> DEV_BSHIFT;
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/* Don't exceed drivers iosize limit */
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if (bp->b_bcount > dev->si_iosize_max)
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bp->b_bcount = dev->si_iosize_max;
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/*
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* Make sure the pbuf can map the request
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* XXX: The pbuf has kvasize = MAXPHYS so a request
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* XXX: larger than MAXPHYS - PAGE_SIZE must be
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* XXX: page aligned or it will be fragmented.
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*/
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iolen = ((vm_offset_t) bp->b_data) & PAGE_MASK;
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if ((bp->b_bcount + iolen) > bp->b_kvasize) {
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bp->b_bcount = bp->b_kvasize;
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if (iolen != 0)
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bp->b_bcount -= PAGE_SIZE;
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}
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bp->b_bufsize = bp->b_bcount;
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blockno = bp->b_offset >> DEV_BSHIFT;
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if ((daddr_t)blockno != blockno) {
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error = EINVAL;
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error = EINVAL; /* blockno overflow */
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goto doerror;
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}
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bp->b_blkno = blockno;
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bp->b_offset = uio->uio_offset;
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if (uio->uio_segflg == UIO_USERSPACE) {
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if (rw && !useracc(bp->b_data, bp->b_bufsize, B_WRITE)) {
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if (!useracc(bp->b_data, bp->b_bufsize,
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bp->b_flags & B_READ)) {
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error = EFAULT;
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goto doerror;
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}
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if (!rw && !useracc(bp->b_data, bp->b_bufsize, B_READ)) {
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error = EFAULT;
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goto doerror;
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}
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/* bring buffer into kernel space */
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vmapbuf(bp);
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}
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/* perform transfer */
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BUF_STRATEGY(bp, 0);
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spl = splbio();
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while ((bp->b_flags & B_DONE) == 0)
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tsleep((caddr_t)bp, PRIBIO, "physstr", 0);
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splx(spl);
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/* release mapping into kernel space */
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if (uio->uio_segflg == UIO_USERSPACE)
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vunmapbuf(bp);
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/*
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* update the uio data
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*/
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{
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int iolen = bp->b_bcount - bp->b_resid;
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if (iolen == 0 && !(bp->b_flags & B_ERROR))
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goto doerror; /* EOF */
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uio->uio_iov[i].iov_len -= iolen;
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uio->uio_iov[i].iov_base += iolen;
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uio->uio_resid -= iolen;
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uio->uio_offset += iolen;
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}
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/*
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* check for an error
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*/
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iolen = bp->b_bcount - bp->b_resid;
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if (iolen == 0 && !(bp->b_flags & B_ERROR))
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goto doerror; /* EOF */
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uio->uio_iov[i].iov_len -= iolen;
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uio->uio_iov[i].iov_base += iolen;
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uio->uio_resid -= iolen;
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uio->uio_offset += iolen;
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if( bp->b_flags & B_ERROR) {
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error = bp->b_error;
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goto doerror;
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}
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}
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}
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doerror:
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relpbuf(bpa, NULL);
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if (!bp_alloc) {
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bp->b_flags &= ~B_PHYS;
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BUF_UNLOCK(bp);
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}
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/*
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* Allow the process UPAGES to be swapped again.
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*/
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relpbuf(bp, NULL);
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PRELE(curproc);
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return (error);
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}
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u_int
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minphys(bp)
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struct buf *bp;
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{
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u_int maxphys;
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maxphys = bp->b_dev->si_iosize_max;
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if(!maxphys) {
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printf("WARNING: %s maxphys = 0 ??\n", devtoname(bp->b_dev));
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maxphys = DFLTPHYS;
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bp->b_dev->si_iosize_max = DFLTPHYS;
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}
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if (bp->b_kvasize && (bp->b_kvasize < maxphys))
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maxphys = bp->b_kvasize;
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if(((vm_offset_t) bp->b_data) & PAGE_MASK) {
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maxphys -= PAGE_SIZE;
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}
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if( bp->b_bcount > maxphys) {
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bp->b_bcount = maxphys;
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}
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return bp->b_bcount;
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}
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static void
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physwakeup(bp)
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struct buf *bp;
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{
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wakeup((caddr_t) bp);
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bp->b_flags &= ~B_CALL;
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}
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@ -480,11 +480,9 @@ int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
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struct ucred *, long, int, struct buf **));
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int cluster_wbuild __P((struct vnode *, long, daddr_t, int));
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void cluster_write __P((struct buf *, u_quad_t));
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int physio __P((struct buf *, dev_t, int, u_int (*)(struct buf *),
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struct uio *));
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int physread __P((dev_t dev, struct uio *uio, int ioflag));
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int physwrite __P((dev_t dev, struct uio *uio, int ioflag));
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u_int minphys __P((struct buf *));
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int physio __P((dev_t dev, struct uio *uio, int ioflag));
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#define physread physio
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#define physwrite physio
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void vfs_bio_set_validclean __P((struct buf *, int base, int size));
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void vfs_bio_clrbuf __P((struct buf *));
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void vfs_busy_pages __P((struct buf *, int clear_modify));
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@ -480,11 +480,9 @@ int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
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struct ucred *, long, int, struct buf **));
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int cluster_wbuild __P((struct vnode *, long, daddr_t, int));
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void cluster_write __P((struct buf *, u_quad_t));
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int physio __P((struct buf *, dev_t, int, u_int (*)(struct buf *),
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struct uio *));
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int physread __P((dev_t dev, struct uio *uio, int ioflag));
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int physwrite __P((dev_t dev, struct uio *uio, int ioflag));
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u_int minphys __P((struct buf *));
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int physio __P((dev_t dev, struct uio *uio, int ioflag));
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#define physread physio
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#define physwrite physio
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void vfs_bio_set_validclean __P((struct buf *, int base, int size));
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void vfs_bio_clrbuf __P((struct buf *));
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void vfs_busy_pages __P((struct buf *, int clear_modify));
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