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
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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 1.13 2007/06/29 00:18:05 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 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)
102 addr = trunc_page((vm_offset_t)ubase);
103 xio->xio_flags = flags;
110 vmprot = (flags & XIOF_WRITE) ? VM_PROT_WRITE : VM_PROT_READ;
111 xio->xio_offset = (vm_offset_t)ubase & PAGE_MASK;
112 xio->xio_pages = xio->xio_internal_pages;
113 if ((n = PAGE_SIZE - xio->xio_offset) > ubytes)
115 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
116 m = vm_fault_page_quick(addr, vmprot, &error);
119 xio->xio_pages[i] = m;
122 if ((n = ubytes) > PAGE_SIZE)
129 * If a failure occured clean out what we loaded and return EFAULT.
130 * Return 0 on success.
132 if (i < XIO_INTERNAL_PAGES && n) {
134 xio->xio_error = EFAULT;
137 return(xio->xio_error);
141 * Initialize an XIO given a kernelspace buffer. 0 is returned on success,
142 * an error code on failure. The actual number of bytes that could be
143 * accomodated in the XIO will be stored in xio_bytes and the page offset
144 * will be stored in xio_offset.
147 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
155 addr = trunc_page((vm_offset_t)kbase);
157 xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
159 xio->xio_pages = xio->xio_internal_pages;
161 if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
163 for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
164 if ((paddr = pmap_kextract(addr)) == 0)
167 m = PHYS_TO_VM_PAGE(paddr);
170 xio->xio_pages[i] = m;
173 if ((n = kbytes) > PAGE_SIZE)
180 * If a failure occured clean out what we loaded and return EFAULT.
181 * Return 0 on success.
183 if (i < XIO_INTERNAL_PAGES && n) {
185 xio->xio_error = EFAULT;
187 return(xio->xio_error);
191 * Cleanup an XIO so it can be destroyed. The pages associated with the
195 xio_release(xio_t xio)
201 for (i = 0; i < xio->xio_npages; ++i) {
202 m = xio->xio_pages[i];
209 xio->xio_error = ENOBUFS;
213 * Copy data between an XIO and a UIO. If the UIO represents userspace it
214 * must be relative to the current context.
216 * uoffset is the abstracted starting offset in the XIO, not the actual
217 * offset, and usually starts at 0.
219 * The XIO is not modified. The UIO is updated to reflect the copy.
221 * UIO_READ xio -> uio
222 * UIO_WRITE uio -> xio
225 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep)
230 bytes = xio->xio_bytes - uoffset;
231 if (bytes > uio->uio_resid)
232 bytes = uio->uio_resid;
233 KKASSERT(bytes >= 0);
234 error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset,
244 * Copy the specified number of bytes from the xio to a userland
245 * buffer. Return an error code or 0 on success.
247 * uoffset is the abstracted starting offset in the XIO, not the actual
248 * offset, and usually starts at 0.
250 * The XIO is not modified.
253 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes)
262 if (uoffset + bytes > xio->xio_bytes)
265 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
266 if ((n = PAGE_SIZE - offset) > bytes)
270 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
274 m = xio->xio_pages[i];
275 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
276 error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n);
281 uptr = (char *)uptr + n;
284 if ((n = bytes) > PAGE_SIZE)
292 * Copy the specified number of bytes from the xio to a kernel
293 * buffer. Return an error code or 0 on success.
295 * uoffset is the abstracted starting offset in the XIO, not the actual
296 * offset, and usually starts at 0.
298 * The XIO is not modified.
301 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes)
310 if (bytes + uoffset > xio->xio_bytes)
313 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
314 if ((n = PAGE_SIZE - offset) > bytes)
318 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
322 m = xio->xio_pages[i];
323 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
324 bcopy((char *)sf_buf_kva(sf) + offset, kptr, n);
327 kptr = (char *)kptr + n;
330 if ((n = bytes) > PAGE_SIZE)
338 * Copy the specified number of bytes from userland to the xio.
339 * Return an error code or 0 on success.
341 * uoffset is the abstracted starting offset in the XIO, not the actual
342 * offset, and usually starts at 0.
344 * Data in pages backing the XIO will be modified.
347 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes)
356 if (uoffset + bytes > xio->xio_bytes)
359 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
360 if ((n = PAGE_SIZE - offset) > bytes)
364 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
368 m = xio->xio_pages[i];
369 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
370 error = copyin(uptr, (char *)sf_buf_kva(sf) + offset, n);
375 uptr = (const char *)uptr + n;
378 if ((n = bytes) > PAGE_SIZE)
386 * Copy the specified number of bytes from the kernel to the xio.
387 * Return an error code or 0 on success.
389 * uoffset is the abstracted starting offset in the XIO, not the actual
390 * offset, and usually starts at 0.
392 * Data in pages backing the XIO will be modified.
395 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes)
404 if (uoffset + bytes > xio->xio_bytes)
407 offset = (xio->xio_offset + uoffset) & PAGE_MASK;
408 if ((n = PAGE_SIZE - offset) > bytes)
412 for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
416 m = xio->xio_pages[i];
417 sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
418 bcopy(kptr, (char *)sf_buf_kva(sf) + offset, n);
421 kptr = (const char *)kptr + n;
424 if ((n = bytes) > PAGE_SIZE)