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
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29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * $DragonFly: src/sys/kern/kern_xio.c,v 1.7 2004/07/16 05:51:10 dillon 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.
91 * Note that you cannot legally accessed a previously cached linmap with
92 * a newly initialized xio until after calling xio_linmap().
95 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags)
105 addr = trunc_page((vm_offset_t)ubase);
106 xio->xio_flags = flags;
113 vmprot = (flags & XIOF_WRITE) ? VM_PROT_WRITE : VM_PROT_READ;
114 xio->xio_offset = (vm_offset_t)ubase & PAGE_MASK;
115 xio->xio_pages = xio->xio_internal_pages;
116 if ((n = PAGE_SIZE - xio->xio_offset) > ubytes)
118 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
119 if (vm_fault_quick((caddr_t)addr, vmprot) < 0)
121 if ((paddr = pmap_kextract(addr)) == 0)
124 m = PHYS_TO_VM_PAGE(paddr);
127 xio->xio_pages[i] = m;
130 if ((n = ubytes) > PAGE_SIZE)
137 * If a failure occured clean out what we loaded and return EFAULT.
138 * Return 0 on success.
140 if (i < XIO_INTERNAL_PAGES && n) {
142 xio->xio_error = EFAULT;
145 return(xio->xio_error);
149 * Initialize an XIO given a kernelspace buffer. 0 is returned on success,
150 * an error code on failure. The actual number of bytes that could be
151 * accomodated in the XIO will be stored in xio_bytes.
153 * vmprot is usually either VM_PROT_READ or VM_PROT_WRITE.
155 * Note that you cannot legally accessed a previously cached linmap with
156 * a newly initialized xio until after calling xio_linmap().
159 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
168 addr = trunc_page((vm_offset_t)kbase);
170 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
172 xio->xio_pages = xio->xio_internal_pages;
174 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
176 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
177 if ((paddr = pmap_kextract(addr)) == 0)
180 m = PHYS_TO_VM_PAGE(paddr);
183 xio->xio_pages[i] = m;
186 if ((n = kbytes) > PAGE_SIZE)
193 * If a failure occured clean out what we loaded and return EFAULT.
194 * Return 0 on success.
196 if (i < XIO_INTERNAL_PAGES && n) {
198 xio->xio_error = EFAULT;
200 return(xio->xio_error);
204 * Cleanup an XIO so it can be destroyed. The pages associated with the
205 * XIO are released. If a linear mapping buffer is active, it will be
206 * unlocked but the mappings will be left intact for optimal reconstitution
207 * in a later xio_linmap() call.
209 * Note that you cannot legally accessed the linmap on a released XIO.
212 xio_release(xio_t xio)
219 for (i = 0; i < xio->xio_npages; ++i) {
220 m = xio->xio_pages[i];
224 if (xio->xio_flags & XIOF_LINMAP) {
225 xio->xio_flags &= ~XIOF_LINMAP;
231 xio->xio_error = ENOBUFS;
235 * Copy data between an XIO and a UIO. If the UIO represents userspace it
236 * must be relative to the current context. Both the UIO and the XIO are
237 * modified, but the XIO's pages are not released when exhausted.
239 * UIO_READ xio -> uio
240 * UIO_WRITE uio -> xio
243 xio_uio_copy(xio_t xio, struct uio *uio, int *sizep)
248 if ((bytes = xio->xio_bytes) > uio->uio_resid)
249 bytes = uio->uio_resid;
250 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset, bytes, uio);
252 xio->xio_bytes -= bytes;
253 xio->xio_offset += bytes;
262 * Copy the specified number of bytes from the xio to a userland
263 * buffer. Return an error code or 0 on success.
265 * The XIO is modified, but the XIO's pages are not released when exhausted.
268 xio_copy_xtou(xio_t xio, void *uptr, int bytes)
277 if (bytes > xio->xio_bytes)
280 offset = xio->xio_offset & PAGE_MASK;
281 if ((n = PAGE_SIZE - offset) > bytes)
285 for (i = xio->xio_offset >> PAGE_SHIFT; i < xio->xio_npages; ++i) {
286 m = xio->xio_pages[i];
287 sf = sf_buf_alloc(m, SFBA_QUICK);
288 error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n);
294 xio->xio_offset += n;
295 uptr = (char *)uptr + n;
298 if ((n = bytes) > PAGE_SIZE)
306 * Copy the specified number of bytes from the xio to a kernel
307 * buffer. Return an error code or 0 on success.
309 * The XIO is modified, but the XIO's pages are not released when exhausted.
312 xio_copy_xtok(xio_t xio, void *kptr, int bytes)
321 if (bytes > xio->xio_bytes)
324 offset = xio->xio_offset & PAGE_MASK;
325 if ((n = PAGE_SIZE - offset) > bytes)
329 for (i = xio->xio_offset >> PAGE_SHIFT; i < xio->xio_npages; ++i) {
330 m = xio->xio_pages[i];
331 sf = sf_buf_alloc(m, SFBA_QUICK);
332 bcopy((char *)sf_buf_kva(sf) + offset, kptr, n);
336 xio->xio_offset += n;
337 kptr = (char *)kptr + n;
340 if ((n = bytes) > PAGE_SIZE)