2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, 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
15 * the documentation and/or other materials provided with the
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_xio.c,v 1.9 2005/03/02 18:42:08 hmp Exp $
37 * Kernel XIO interface. An initialized XIO is basically a collection of
38 * appropriately held vm_page_t's. XIO buffers are vmspace agnostic and
39 * can represent userspace or kernelspace buffers, and can be passed to
40 * foreign threads outside of the originating vmspace. XIO buffers are
41 * not mapped into KVM and thus can be manipulated and passed around with
44 * The intent is for XIO to be used in the I/O path, VFS, CAPS, and other
45 * places that need to pass (possibly userspace) data between threads.
47 * TODO: check for busy page when modifying, check writeable.
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/malloc.h>
54 #include <sys/vmmeter.h>
55 #include <sys/vnode.h>
57 #include <sys/sfbuf.h>
60 #include <vm/vm_param.h>
62 #include <vm/vm_kern.h>
64 #include <vm/vm_map.h>
65 #include <vm/vm_object.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_pageout.h>
68 #include <vm/vm_pager.h>
69 #include <vm/vm_extern.h>
70 #include <vm/vm_page2.h>
73 * Just do basic initialization of an empty XIO
83 xio->xio_pages = xio->xio_internal_pages;
87 * Initialize an XIO given a userspace buffer. 0 is returned on success,
88 * an error code on failure. The actual number of bytes that could be
89 * accomodated in the XIO will be stored in xio_bytes and the page offset
90 * will be stored in xio_offset.
93 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags)
103 addr = trunc_page((vm_offset_t)ubase);
104 xio->xio_flags = flags;
111 vmprot = (flags & XIOF_WRITE) ? VM_PROT_WRITE : VM_PROT_READ;
112 xio->xio_offset = (vm_offset_t)ubase & PAGE_MASK;
113 xio->xio_pages = xio->xio_internal_pages;
114 if ((n = PAGE_SIZE - xio->xio_offset) > ubytes)
116 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
117 if (vm_fault_quick((caddr_t)addr, vmprot) < 0)
119 if ((paddr = pmap_kextract(addr)) == 0)
122 m = PHYS_TO_VM_PAGE(paddr);
125 xio->xio_pages[i] = m;
128 if ((n = ubytes) > PAGE_SIZE)
135 * If a failure occured clean out what we loaded and return EFAULT.
136 * Return 0 on success.
138 if (i < XIO_INTERNAL_PAGES && n) {
140 xio->xio_error = EFAULT;
143 return(xio->xio_error);
147 * Initialize an XIO given a kernelspace buffer. 0 is returned on success,
148 * an error code on failure. The actual number of bytes that could be
149 * accomodated in the XIO will be stored in xio_bytes and the page offset
150 * will be stored in xio_offset.
153 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
162 addr = trunc_page((vm_offset_t)kbase);
164 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
166 xio->xio_pages = xio->xio_internal_pages;
168 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
170 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
171 if ((paddr = pmap_kextract(addr)) == 0)
174 m = PHYS_TO_VM_PAGE(paddr);
177 xio->xio_pages[i] = m;
180 if ((n = kbytes) > PAGE_SIZE)
187 * If a failure occured clean out what we loaded and return EFAULT.
188 * Return 0 on success.
190 if (i < XIO_INTERNAL_PAGES && n) {
192 xio->xio_error = EFAULT;
194 return(xio->xio_error);
198 * Cleanup an XIO so it can be destroyed. The pages associated with the
202 xio_release(xio_t xio)
209 for (i = 0; i < xio->xio_npages; ++i) {
210 m = xio->xio_pages[i];
217 xio->xio_error = ENOBUFS;
221 * Copy data between an XIO and a UIO. If the UIO represents userspace it
222 * must be relative to the current context.
224 * uoffset is the abstracted starting offset in the XIO, not the actual
225 * offset, and usually starts at 0.
227 * The XIO is not modified. The UIO is updated to reflect the copy.
229 * UIO_READ xio -> uio
230 * UIO_WRITE uio -> xio
233 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep)
238 bytes = xio->xio_bytes - uoffset;
239 if (bytes > uio->uio_resid)
240 bytes = uio->uio_resid;
241 KKASSERT(bytes >= 0);
242 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset,
252 * Copy the specified number of bytes from the xio to a userland
253 * buffer. Return an error code or 0 on success.
255 * uoffset is the abstracted starting offset in the XIO, not the actual
256 * offset, and usually starts at 0.
258 * The XIO is not modified.
261 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes)
270 if (bytes > xio->xio_bytes)
273 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
274 if ((n = PAGE_SIZE - offset) > bytes)
278 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
282 m = xio->xio_pages[i];
283 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
284 error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n);
289 uptr = (char *)uptr + n;
292 if ((n = bytes) > PAGE_SIZE)
300 * Copy the specified number of bytes from the xio to a kernel
301 * buffer. Return an error code or 0 on success.
303 * uoffset is the abstracted starting offset in the XIO, not the actual
304 * offset, and usually starts at 0.
306 * The XIO is not modified.
309 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes)
318 if (bytes + uoffset > xio->xio_bytes)
321 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
322 if ((n = PAGE_SIZE - offset) > bytes)
326 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
330 m = xio->xio_pages[i];
331 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
332 bcopy((char *)sf_buf_kva(sf) + offset, kptr, n);
335 kptr = (char *)kptr + n;
338 if ((n = bytes) > PAGE_SIZE)