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 1.16 2008/05/09 07:24:45 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.  Do not dirty the pages.
 146          */
 147         if (i < XIO_INTERNAL_PAGES && n) {
 148             xio->xio_flags &= ~XIOF_WRITE;
 149             xio_release(xio);
 150             xio->xio_error = EFAULT;
 151         }
 152     }
 153     return(xio->xio_error);
 154 }
 155
 156 /*
 157  * Initialize an XIO given a kernelspace buffer.  0 is returned on success,
 158  * an error code on failure.  The actual number of bytes that could be
 159  * accomodated in the XIO will be stored in xio_bytes and the page offset
 160  * will be stored in xio_offset.
 161  */
 162 int
 163 xio_init_kbuf(xio_t xio, void *kbase, size_t kbytes)
 164 {
 165     vm_offset_t addr;
 166     vm_paddr_t paddr;
 167     vm_page_t m;
 168     int i;
 169     int n;
 170
 171     addr = trunc_page((vm_offset_t)kbase);
 172     xio->xio_flags = 0;
 173     xio->xio_offset = (vm_offset_t)kbase & PAGE_MASK;
 174     xio->xio_bytes = 0;
 175     xio->xio_pages = xio->xio_internal_pages;
 176     xio->xio_error = 0;
 177     if ((n = PAGE_SIZE - xio->xio_offset) > kbytes)
 178         n = kbytes;
 179     for (i = 0; n && i < XIO_INTERNAL_PAGES; ++i) {
 180         if ((paddr = pmap_kextract(addr)) == 0)
 181             break;
 182         crit_enter();
 183         m = PHYS_TO_VM_PAGE(paddr);
 184         vm_page_hold(m);
 185         crit_exit();
 186         xio->xio_pages[i] = m;
 187         kbytes -= n;
 188         xio->xio_bytes += n;
 189         if ((n = kbytes) > PAGE_SIZE)
 190             n = PAGE_SIZE;
 191         addr += PAGE_SIZE;
 192     }
 193     xio->xio_npages = i;
 194
 195     /*
 196      * If a failure occured clean out what we loaded and return EFAULT.
 197      * Return 0 on success.
 198      */
 199     if (i < XIO_INTERNAL_PAGES && n) {
 200         xio_release(xio);
 201         xio->xio_error = EFAULT;
 202     }
 203     return(xio->xio_error);
 204 }
 205
 206 /*
 207  * Initialize an XIO given an array of vm_page pointers.  The caller is
 208  * responsible for any modified state changes for the pages.
 209  */
 210 int
 211 xio_init_pages(xio_t xio, struct vm_page **mbase, int npages, int xflags)
 212 {
 213     int i;
 214
 215     KKASSERT(npages <= XIO_INTERNAL_PAGES);
 216
 217     xio->xio_flags = xflags;
 218     xio->xio_offset = 0;
 219     xio->xio_bytes = 0;
 220     xio->xio_pages = xio->xio_internal_pages;
 221     xio->xio_npages = npages;
 222     xio->xio_error = 0;
 223     crit_enter();
 224     for (i = 0; i < npages; ++i) {
 225         vm_page_hold(mbase[i]);
 226         xio->xio_pages[i] = mbase[i];
 227     }
 228     crit_exit();
 229     return(0);
 230 }
 231
 232 /*
 233  * Cleanup an XIO so it can be destroyed.  The pages associated with the
 234  * XIO are released.
 235  */
 236 void
 237 xio_release(xio_t xio)
 238 {
 239     int i;
 240     vm_page_t m;
 241
 242     crit_enter();
 243     for (i = 0; i < xio->xio_npages; ++i) {
 244         m = xio->xio_pages[i];
 245         if (xio->xio_flags & XIOF_WRITE)
 246                 vm_page_dirty(m);
 247         vm_page_unhold(m);
 248     }
 249     crit_exit();
 250     xio->xio_offset = 0;
 251     xio->xio_npages = 0;
 252     xio->xio_bytes = 0;
 253     xio->xio_error = ENOBUFS;
 254 }
 255
 256 /*
 257  * Copy data between an XIO and a UIO.  If the UIO represents userspace it
 258  * must be relative to the current context.
 259  *
 260  * uoffset is the abstracted starting offset in the XIO, not the actual
 261  * offset, and usually starts at 0.
 262  *
 263  * The XIO is not modified.  The UIO is updated to reflect the copy.
 264  *
 265  * UIO_READ     xio -> uio
 266  * UIO_WRITE    uio -> xio
 267  */
 268 int
 269 xio_uio_copy(xio_t xio, int uoffset, struct uio *uio, int *sizep)
 270 {
 271     int error;
 272     int bytes;
 273
 274     bytes = xio->xio_bytes - uoffset;
 275     if (bytes > uio->uio_resid)
 276         bytes = uio->uio_resid;
 277     KKASSERT(bytes >= 0);
 278     error = uiomove_fromphys(xio->xio_pages, xio->xio_offset + uoffset,
 279                                 bytes, uio);
 280     if (error == 0)
 281         *sizep = bytes;
 282     else
 283         *sizep = 0;
 284     return(error);
 285 }
 286
 287 /*
 288  * Copy the specified number of bytes from the xio to a userland
 289  * buffer.  Return an error code or 0 on success.
 290  *
 291  * uoffset is the abstracted starting offset in the XIO, not the actual
 292  * offset, and usually starts at 0.
 293  *
 294  * The XIO is not modified.
 295  */
 296 int
 297 xio_copy_xtou(xio_t xio, int uoffset, void *uptr, int bytes)
 298 {
 299     int i;
 300     int n;
 301     int error;
 302     int offset;
 303     vm_page_t m;
 304     struct sf_buf *sf;
 305
 306     if (uoffset + bytes > xio->xio_bytes)
 307         return(EFAULT);
 308
 309     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 310     if ((n = PAGE_SIZE - offset) > bytes)
 311         n = bytes;
 312
 313     error = 0;
 314     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 315          i < xio->xio_npages;
 316          ++i
 317     ) {
 318         m = xio->xio_pages[i];
 319         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 320         error = copyout((char *)sf_buf_kva(sf) + offset, uptr, n);
 321         sf_buf_free(sf);
 322         if (error)
 323             break;
 324         bytes -= n;
 325         uptr = (char *)uptr + n;
 326         if (bytes == 0)
 327             break;
 328         if ((n = bytes) > PAGE_SIZE)
 329             n = PAGE_SIZE;
 330         offset = 0;
 331     }
 332     return(error);
 333 }
 334
 335 /*
 336  * Copy the specified number of bytes from the xio to a kernel
 337  * buffer.  Return an error code or 0 on success.
 338  *
 339  * uoffset is the abstracted starting offset in the XIO, not the actual
 340  * offset, and usually starts at 0.
 341  *
 342  * The XIO is not modified.
 343  */
 344 int
 345 xio_copy_xtok(xio_t xio, int uoffset, void *kptr, int bytes)
 346 {
 347     int i;
 348     int n;
 349     int error;
 350     int offset;
 351     vm_page_t m;
 352     struct sf_buf *sf;
 353
 354     if (bytes + uoffset > xio->xio_bytes)
 355         return(EFAULT);
 356
 357     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 358     if ((n = PAGE_SIZE - offset) > bytes)
 359         n = bytes;
 360
 361     error = 0;
 362     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 363          i < xio->xio_npages;
 364          ++i
 365     ) {
 366         m = xio->xio_pages[i];
 367         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 368         bcopy((char *)sf_buf_kva(sf) + offset, kptr, n);
 369         sf_buf_free(sf);
 370         bytes -= n;
 371         kptr = (char *)kptr + n;
 372         if (bytes == 0)
 373             break;
 374         if ((n = bytes) > PAGE_SIZE)
 375             n = PAGE_SIZE;
 376         offset = 0;
 377     }
 378     return(error);
 379 }
 380
 381 /*
 382  * Copy the specified number of bytes from userland to the xio.
 383  * Return an error code or 0 on success.
 384  *
 385  * uoffset is the abstracted starting offset in the XIO, not the actual
 386  * offset, and usually starts at 0.
 387  *
 388  * Data in pages backing the XIO will be modified.
 389  */
 390 int
 391 xio_copy_utox(xio_t xio, int uoffset, const void *uptr, int bytes)
 392 {
 393     int i;
 394     int n;
 395     int error;
 396     int offset;
 397     vm_page_t m;
 398     struct sf_buf *sf;
 399
 400     if (uoffset + bytes > xio->xio_bytes)
 401         return(EFAULT);
 402
 403     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 404     if ((n = PAGE_SIZE - offset) > bytes)
 405         n = bytes;
 406
 407     error = 0;
 408     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 409          i < xio->xio_npages;
 410          ++i
 411     ) {
 412         m = xio->xio_pages[i];
 413         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 414         error = copyin(uptr, (char *)sf_buf_kva(sf) + offset, n);
 415         sf_buf_free(sf);
 416         if (error)
 417             break;
 418         bytes -= n;
 419         uptr = (const char *)uptr + n;
 420         if (bytes == 0)
 421             break;
 422         if ((n = bytes) > PAGE_SIZE)
 423             n = PAGE_SIZE;
 424         offset = 0;
 425     }
 426     return(error);
 427 }
 428
 429 /*
 430  * Copy the specified number of bytes from the kernel to the xio.
 431  * Return an error code or 0 on success.
 432  *
 433  * uoffset is the abstracted starting offset in the XIO, not the actual
 434  * offset, and usually starts at 0.
 435  *
 436  * Data in pages backing the XIO will be modified.
 437  */
 438 int
 439 xio_copy_ktox(xio_t xio, int uoffset, const void *kptr, int bytes)
 440 {
 441     int i;
 442     int n;
 443     int error;
 444     int offset;
 445     vm_page_t m;
 446     struct sf_buf *sf;
 447
 448     if (uoffset + bytes > xio->xio_bytes)
 449         return(EFAULT);
 450
 451     offset = (xio->xio_offset + uoffset) & PAGE_MASK;
 452     if ((n = PAGE_SIZE - offset) > bytes)
 453         n = bytes;
 454
 455     error = 0;
 456     for (i = (xio->xio_offset + uoffset) >> PAGE_SHIFT;
 457          i < xio->xio_npages;
 458          ++i
 459     ) {
 460         m = xio->xio_pages[i];
 461         sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
 462         bcopy(kptr, (char *)sf_buf_kva(sf) + offset, n);
 463         sf_buf_free(sf);
 464         bytes -= n;
 465         kptr = (const char *)kptr + n;
 466         if (bytes == 0)
 467             break;
 468         if ((n = bytes) > PAGE_SIZE)
 469             n = PAGE_SIZE;
 470         offset = 0;
 471     }
 472     return(error);
 473 }