sys/kern/kern_xio.c

   1 /*
   2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Matthew Dillon <dillon@backplane.com>
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  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
  16  *    distribution.
  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.
  20  *
  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
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/sys/kern/kern_xio.c,v 1.15 2007/08/13 17:20:04 dillon Exp $
  35  */
  36 /*
  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
  42  * very low overheads.
  43  *
  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.
  46  *
  47  * TODO: check for busy page when modifying, check writeable.
  48  */
  49
  50 #include <sys/param.h>
  51 #include <sys/systm.h>
  52 #include <sys/malloc.h>
  53 #include <sys/proc.h>
  54 #include <sys/vmmeter.h>
  55 #include <sys/vnode.h>
  56 #include <sys/xio.h>
  57 #include <sys/sfbuf.h>
  58
  59 #include <vm/vm.h>
  60 #include <vm/vm_param.h>
  61 #include <sys/lock.h>
  62 #include <vm/vm_kern.h>
  63 #include <vm/pmap.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>
  71
  72 /*
  73  * Just do basic initialization of an empty XIO
  74  */
  75 void
  76 xio_init(xio_t xio)
  77 {
  78     xio->xio_flags = 0;
  79     xio->xio_bytes = 0;
  80     xio->xio_error = 0;
  81     xio->xio_offset = 0;
  82     xio->xio_npages = 0;
  83     xio->xio_pages = xio->xio_internal_pages;
  84 }
  85
  86 /*
  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.
  91  */
  92 int
  93 xio_init_ubuf(xio_t xio, void *ubase, size_t ubytes, int flags)
  94 {
  95     vm_offset_t addr;
  96     vm_page_t m;
  97     vm_page_t m0;
  98     int error;
  99     int i;
 100     int n;
 101     int vmprot;
 102
 103     addr = trunc_page((vm_offset_t)ubase);
 104     xio->xio_flags = flags;
 105     xio->xio_bytes = 0;
 106     xio->xio_error = 0;
 107     if (ubytes == 0) {
 108         xio->xio_offset = 0;
 109         xio->xio_npages = 0;
 110     } else {
 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)
 115             n = ubytes;
 116         m0 = NULL;
 117         for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
 118             m = vm_fault_page_quick(addr, vmprot, &error);
 119             if (m == NULL)
 120                 break;
 121             xio->xio_pages[i] = m;
 122             ubytes -= n;
 123             xio->xio_bytes += n;
 124             if ((n = ubytes) > PAGE_SIZE)
 125                 n = PAGE_SIZE;
 126             addr += PAGE_SIZE;
 127
 128             /*
 129              * Check linearity, used by syslink to memory map DMA buffers.
 130              */
 131             if (flags & XIOF_VMLINEAR) {
 132                 if (i == 0) {
 133                     m0 = m;
 134                 } else
 135                 if (m->object != m0->object || m->pindex != m0->pindex + i) {
 136                     error = EINVAL;
 137                     break;
 138                 }
 139             }
 140         }
 141         xio->xio_npages = i;
 142
 143         /*
 144          * If a failure occured clean out what we loaded and return EFAULT.
 145          * Return 0 on success.
 146          */
 147         if (i < XIO_INTERNAL_PAGES && n) {
 148             xio_release(xio);
 149             xio->xio_error = EFAULT;
 150         }
 151     }
 152     return(xio->xio_error);
 153 }
 154
 155 /*
 156  * Initialize an XIO given a kernelspace buffer.  0 is returned on success,
 157  * an error code on failure.  The actual number of bytes that could be
 158  * accomodated in the XIO will be stored in xio_bytes and the page offset
 159  * will be stored in xio_offset.
 160  */
 161 int
 162 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
 163 {
 164     vm_offset_t addr;
 165     vm_paddr_t paddr;
 166     vm_page_t m;
 167     int i;
 168     int n;
 169
 170     addr = trunc_page((vm_offset_t)kbase);
 171     xio->xio_flags = 0;
 172     xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
 173     xio->xio_bytes = 0;
 174     xio->xio_pages = xio->xio_internal_pages;
 175     xio->xio_error = 0;
 176     if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
 177         n = kbytes;
 178     for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
 179         if ((paddr = pmap_kextract(addr)) == 0)
 180             break;
 181         crit_enter();
 182         m = PHYS_TO_VM_PAGE(paddr);
 183         vm_page_hold(m);
 184         crit_exit();
 185         xio->xio_pages[i] = m;
 186         kbytes -= n;
 187         xio->xio_bytes += n;
 188         if ((n = kbytes) > PAGE_SIZE)
 189             n = PAGE_SIZE;
 190         addr += PAGE_SIZE;
 191     }
 192     xio->xio_npages = i;
 193
 194     /*
 195      * If a failure occured clean out what we loaded and return EFAULT.
 196      * Return 0 on success.
 197      */
 198     if (i < XIO_INTERNAL_PAGES && n) {
 199         xio_release(xio);
 200         xio->xio_error = EFAULT;
 201     }
 202     return(xio->xio_error);
 203 }
 204
 205 /*
 206  * Initialize an XIO given an array of vm_page pointers.
 207  */
 208 int
 209 xio_init_pages(xio_t xio, struct vm_page **mbase, int npages, int xflags)
 210 {
 211     int i;
 212
 213     KKASSERT(npages <= XIO_INTERNAL_PAGES);
 214
 215     xio->xio_flags = xflags;
 216     xio->xio_offset = 0;
 217     xio->xio_bytes = 0;
 218     xio->xio_pages = xio->xio_internal_pages;
 219     xio->xio_npages = npages;
 220     xio->xio_error = 0;
 221     crit_enter();
 222     for (i = 0; i < npages; ++i) {
 223         vm_page_hold(mbase[i]);
 224         xio->xio_pages[i] = mbase[i];
 225     }
 226     crit_exit();
 227     return(0);
 228 }
 229
 230 /*
 231  * Cleanup an XIO so it can be destroyed.  The pages associated with the
 232  * XIO are released.
 233  */
 234 void
 235 xio_release(xio_t xio)
 236 {
 237     int i;
 238     vm_page_t m;
 239
 240     crit_enter();
 241     for (i = 0; i < xio->xio_npages; ++i) {
 242         m = xio->xio_pages[i];
 243         vm_page_unhold(m);
 244     }
 245     crit_exit();
 246     xio->xio_offset = 0;
 247     xio->xio_npages = 0;
 248     xio->xio_bytes = 0;
 249     xio->xio_error = ENOBUFS;
 250 }
 251
 252 /*
 253  * Copy data between an XIO and a UIO.  If the UIO represents userspace it
 254  * must be relative to the current context.
 255  *
 256  * uoffset is the abstracted starting offset in the XIO, not the actual
 257  * offset, and usually starts at 0.
 258  *
 259  * The XIO is not modified.  The UIO is updated to reflect the copy.
 260  *
 261  * UIO_READ     xio -> uio
 262  * UIO_WRITE    uio -> xio
 263  */
 264 int
 265 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep)
 266 {
 267     int error;
 268     int bytes;
 269
 270     bytes = xio->xio_bytes - uoffset;
 271     if (bytes > uio->uio_resid)
 272         bytes = uio->uio_resid;
 273     KKASSERT(bytes >= 0);
 274     error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset,
 275                                 bytes, uio);
 276     if (error == 0)
 277         *sizep = bytes;
 278     else
 279         *sizep = 0;
 280     return(error);
 281 }
 282
 283 /*
 284  * Copy the specified number of bytes from the xio to a userland
 285  * buffer.  Return an error code or 0 on success.
 286  *
 287  * uoffset is the abstracted starting offset in the XIO, not the actual
 288  * offset, and usually starts at 0.
 289  *
 290  * The XIO is not modified.
 291  */
 292 int
 293 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes)
 294 {
 295     int i;
 296     int n;
 297     int error;
 298     int offset;
 299     vm_page_t m;
 300     struct sf_buf *sf;
 301
 302     if (uoffset + bytes > xio->xio_bytes)
 303         return(EFAULT);
 304
 305     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 306     if ((n = PAGE_SIZE - offset) > bytes)
 307         n = bytes;
 308
 309     error = 0;
 310     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 311          i < xio->xio_npages;
 312          ++i
 313     ) {
 314         m = xio->xio_pages[i];
 315         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 316         error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n);
 317         sf_buf_free(sf);
 318         if (error)
 319             break;
 320         bytes -= n;
 321         uptr = (char *)uptr + n;
 322         if (bytes == 0)
 323             break;
 324         if ((n = bytes) > PAGE_SIZE)
 325             n = PAGE_SIZE;
 326         offset = 0;
 327     }
 328     return(error);
 329 }
 330
 331 /*
 332  * Copy the specified number of bytes from the xio to a kernel
 333  * buffer.  Return an error code or 0 on success.
 334  *
 335  * uoffset is the abstracted starting offset in the XIO, not the actual
 336  * offset, and usually starts at 0.
 337  *
 338  * The XIO is not modified.
 339  */
 340 int
 341 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes)
 342 {
 343     int i;
 344     int n;
 345     int error;
 346     int offset;
 347     vm_page_t m;
 348     struct sf_buf *sf;
 349
 350     if (bytes + uoffset > xio->xio_bytes)
 351         return(EFAULT);
 352
 353     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 354     if ((n = PAGE_SIZE - offset) > bytes)
 355         n = bytes;
 356
 357     error = 0;
 358     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 359          i < xio->xio_npages;
 360          ++i
 361     ) {
 362         m = xio->xio_pages[i];
 363         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 364         bcopy((char *)sf_buf_kva(sf) + offset, kptr, n);
 365         sf_buf_free(sf);
 366         bytes -= n;
 367         kptr = (char *)kptr + n;
 368         if (bytes == 0)
 369             break;
 370         if ((n = bytes) > PAGE_SIZE)
 371             n = PAGE_SIZE;
 372         offset = 0;
 373     }
 374     return(error);
 375 }
 376
 377 /*
 378  * Copy the specified number of bytes from userland to the xio.
 379  * Return an error code or 0 on success.
 380  *
 381  * uoffset is the abstracted starting offset in the XIO, not the actual
 382  * offset, and usually starts at 0.
 383  *
 384  * Data in pages backing the XIO will be modified.
 385  */
 386 int
 387 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes)
 388 {
 389     int i;
 390     int n;
 391     int error;
 392     int offset;
 393     vm_page_t m;
 394     struct sf_buf *sf;
 395
 396     if (uoffset + bytes > xio->xio_bytes)
 397         return(EFAULT);
 398
 399     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 400     if ((n = PAGE_SIZE - offset) > bytes)
 401         n = bytes;
 402
 403     error = 0;
 404     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 405          i < xio->xio_npages;
 406          ++i
 407     ) {
 408         m = xio->xio_pages[i];
 409         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 410         error = copyin(uptr, (char *)sf_buf_kva(sf) + offset, n);
 411         sf_buf_free(sf);
 412         if (error)
 413             break;
 414         bytes -= n;
 415         uptr = (const char *)uptr + n;
 416         if (bytes == 0)
 417             break;
 418         if ((n = bytes) > PAGE_SIZE)
 419             n = PAGE_SIZE;
 420         offset = 0;
 421     }
 422     return(error);
 423 }
 424
 425 /*
 426  * Copy the specified number of bytes from the kernel to the xio.
 427  * Return an error code or 0 on success.
 428  *
 429  * uoffset is the abstracted starting offset in the XIO, not the actual
 430  * offset, and usually starts at 0.
 431  *
 432  * Data in pages backing the XIO will be modified.
 433  */
 434 int
 435 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes)
 436 {
 437     int i;
 438     int n;
 439     int error;
 440     int offset;
 441     vm_page_t m;
 442     struct sf_buf *sf;
 443
 444     if (uoffset + bytes > xio->xio_bytes)
 445         return(EFAULT);
 446
 447     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 448     if ((n = PAGE_SIZE - offset) > bytes)
 449         n = bytes;
 450
 451     error = 0;
 452     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 453          i < xio->xio_npages;
 454          ++i
 455     ) {
 456         m = xio->xio_pages[i];
 457         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 458         bcopy(kptr, (char *)sf_buf_kva(sf) + offset, n);
 459         sf_buf_free(sf);
 460         bytes -= n;
 461         kptr = (const char *)kptr + n;
 462         if (bytes == 0)
 463             break;
 464         if ((n = bytes) > PAGE_SIZE)
 465             n = PAGE_SIZE;
 466         offset = 0;
 467     }
 468     return(error);
 469 }