md.c

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    1 /*      $NetBSD: md.c,v 1.47 2006/11/16 01:32:45 christos Exp $ */
    2 
    3 /*
    4  * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
    5  * All rights reserved.
    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  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above copyright
   13  *    notice, this list of conditions and the following disclaimer in the
   14  *    documentation and/or other materials provided with the distribution.
   15  * 3. The name of the author may not be used to endorse or promote products
   16  *    derived from this software without specific prior written permission.
   17  * 4. All advertising materials mentioning features or use of this software
   18  *    must display the following acknowledgement:
   19  *      This product includes software developed by
   20  *                      Gordon W. Ross and Leo Weppelman.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   32  */
   33 
   34 /*
   35  * This implements a general-purpose memory-disk.
   36  * See md.h for notes on the config types.
   37  *
   38  * Note that this driver provides the same functionality
   39  * as the MFS filesystem hack, but this is better because
   40  * you can use this for any filesystem type you'd like!
   41  *
   42  * Credit for most of the kmem ramdisk code goes to:
   43  *   Leo Weppelman (atari) and Phil Nelson (pc532)
   44  * Credit for the ideas behind the "user space memory" code goes
   45  * to the authors of the MFS implementation.
   46  */
   47 
   48 #include <sys/cdefs.h>
   49 __KERNEL_RCSID(0, "$NetBSD: md.c,v 1.47 2006/11/16 01:32:45 christos Exp $");
   50 
   51 #include "opt_md.h"
   52 
   53 #include <sys/param.h>
   54 #include <sys/kernel.h>
   55 #include <sys/malloc.h>
   56 #include <sys/systm.h>
   57 #include <sys/buf.h>
   58 #include <sys/bufq.h>
   59 #include <sys/device.h>
   60 #include <sys/disk.h>
   61 #include <sys/proc.h>
   62 #include <sys/conf.h>
   63 #include <sys/disklabel.h>
   64 
   65 #include <uvm/uvm_extern.h>
   66 
   67 #include <dev/md.h>
   68 
   69 /*
   70  * By default, include the user-space functionality.
   71  * Use  `options MEMORY_DISK_SERVER=0' to turn it off.
   72  */
   73 #ifndef MEMORY_DISK_SERVER
   74 #define MEMORY_DISK_SERVER 1
   75 #endif  /* MEMORY_DISK_SERVER */
   76 
   77 /*
   78  * We should use the raw partition for ioctl.
   79  */
   80 #define MD_MAX_UNITS    0x10
   81 #define MD_UNIT(unit)   DISKUNIT(unit)
   82 
   83 /* autoconfig stuff... */
   84 
   85 struct md_softc {
   86         struct device sc_dev;   /* REQUIRED first entry */
   87         struct disk sc_dkdev;   /* hook for generic disk handling */
   88         struct md_conf sc_md;
   89         struct bufq_state *sc_buflist;
   90 };
   91 /* shorthand for fields in sc_md: */
   92 #define sc_addr sc_md.md_addr
   93 #define sc_size sc_md.md_size
   94 #define sc_type sc_md.md_type
   95 
   96 void    mdattach(int);
   97 
   98 static void     md_attach(struct device *, struct device *, void *);
   99 
  100 static dev_type_open(mdopen);
  101 static dev_type_close(mdclose);
  102 static dev_type_read(mdread);
  103 static dev_type_write(mdwrite);
  104 static dev_type_ioctl(mdioctl);
  105 static dev_type_strategy(mdstrategy);
  106 static dev_type_size(mdsize);
  107 
  108 const struct bdevsw md_bdevsw = {
  109         mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK
  110 };
  111 
  112 const struct cdevsw md_cdevsw = {
  113         mdopen, mdclose, mdread, mdwrite, mdioctl,
  114         nostop, notty, nopoll, nommap, nokqfilter, D_DISK
  115 };
  116 
  117 static struct dkdriver mddkdriver = { mdstrategy, NULL };
  118 
  119 static int   ramdisk_ndevs;
  120 static void *ramdisk_devs[MD_MAX_UNITS];
  121 
  122 /*
  123  * This is called if we are configured as a pseudo-device
  124  */
  125 void
  126 mdattach(int n)
  127 {
  128         struct md_softc *sc;
  129         int i;
  130 
  131 #ifdef  DIAGNOSTIC
  132         if (ramdisk_ndevs) {
  133                 aprint_error("ramdisk: multiple attach calls?\n");
  134                 return;
  135         }
  136 #endif
  137 
  138         /* XXX:  Are we supposed to provide a default? */
  139         if (n <= 1)
  140                 n = 1;
  141         if (n > MD_MAX_UNITS)
  142                 n = MD_MAX_UNITS;
  143         ramdisk_ndevs = n;
  144 
  145         /* Attach as if by autoconfig. */
  146         for (i = 0; i < n; i++) {
  147 
  148                 sc = malloc(sizeof(*sc), M_DEVBUF, M_NOWAIT|M_ZERO);
  149                 if (!sc) {
  150                         aprint_error("ramdisk: malloc for attach failed!\n");
  151                         return;
  152                 }
  153                 ramdisk_devs[i] = sc;
  154                 sc->sc_dev.dv_unit = i;
  155                 snprintf(sc->sc_dev.dv_xname, sizeof(sc->sc_dev.dv_xname),
  156                     "md%d", i);
  157                 md_attach(NULL, &sc->sc_dev, NULL);
  158         }
  159 }
  160 
  161 static void
  162 md_attach(struct device *parent, struct device *self,
  163     void *aux)
  164 {
  165         struct md_softc *sc = (struct md_softc *)self;
  166 
  167         bufq_alloc(&sc->sc_buflist, "fcfs", 0);
  168 
  169         /* XXX - Could accept aux info here to set the config. */
  170 #ifdef  MEMORY_DISK_HOOKS
  171         /*
  172          * This external function might setup a pre-loaded disk.
  173          * All it would need to do is setup the md_conf struct.
  174          * See sys/dev/md_root.c for an example.
  175          */
  176         md_attach_hook(device_unit(&sc->sc_dev), &sc->sc_md);
  177 #endif
  178 
  179         /*
  180          * Initialize and attach the disk structure.
  181          */
  182         sc->sc_dkdev.dk_driver = &mddkdriver;
  183         sc->sc_dkdev.dk_name = sc->sc_dev.dv_xname;
  184         disk_attach(&sc->sc_dkdev);
  185 }
  186 
  187 /*
  188  * operational routines:
  189  * open, close, read, write, strategy,
  190  * ioctl, dump, size
  191  */
  192 
  193 #if MEMORY_DISK_SERVER
  194 static int      md_server_loop(struct md_softc *sc);
  195 static int      md_ioctl_server(struct md_softc *sc, struct md_conf *umd,
  196                     struct lwp *l);
  197 #endif  /* MEMORY_DISK_SERVER */
  198 static int      md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd,
  199                     struct lwp *l);
  200 
  201 static int
  202 mdsize(dev_t dev)
  203 {
  204         int unit;
  205         struct md_softc *sc;
  206 
  207         unit = MD_UNIT(dev);
  208         if (unit >= ramdisk_ndevs)
  209                 return 0;
  210         sc = ramdisk_devs[unit];
  211         if (sc == NULL)
  212                 return 0;
  213 
  214         if (sc->sc_type == MD_UNCONFIGURED)
  215                 return 0;
  216 
  217         return (sc->sc_size >> DEV_BSHIFT);
  218 }
  219 
  220 static int
  221 mdopen(dev_t dev, int flag, int fmt, struct lwp *l)
  222 {
  223         int unit;
  224         struct md_softc *sc;
  225 
  226         unit = MD_UNIT(dev);
  227         if (unit >= ramdisk_ndevs)
  228                 return ENXIO;
  229         sc = ramdisk_devs[unit];
  230         if (sc == NULL)
  231                 return ENXIO;
  232 
  233         /*
  234          * The raw partition is used for ioctl to configure.
  235          */
  236         if (DISKPART(dev) == RAW_PART)
  237                 return 0;
  238 
  239 #ifdef  MEMORY_DISK_HOOKS
  240         /* Call the open hook to allow loading the device. */
  241         md_open_hook(unit, &sc->sc_md);
  242 #endif
  243 
  244         /*
  245          * This is a normal, "slave" device, so
  246          * enforce initialized.
  247          */
  248         if (sc->sc_type == MD_UNCONFIGURED)
  249                 return ENXIO;
  250 
  251         return 0;
  252 }
  253 
  254 static int
  255 mdclose(dev_t dev, int flag, int fmt, struct lwp *l)
  256 {
  257         int unit;
  258 
  259         unit = MD_UNIT(dev);
  260 
  261         if (unit >= ramdisk_ndevs)
  262                 return ENXIO;
  263 
  264         return 0;
  265 }
  266 
  267 static int
  268 mdread(dev_t dev, struct uio *uio, int flags)
  269 {
  270         int unit;
  271         struct md_softc *sc;
  272 
  273         unit = MD_UNIT(dev);
  274 
  275         if (unit >= ramdisk_ndevs)
  276                 return ENXIO;
  277 
  278         sc = ramdisk_devs[unit];
  279 
  280         if (sc->sc_type == MD_UNCONFIGURED)
  281                 return ENXIO;
  282 
  283         return (physio(mdstrategy, NULL, dev, B_READ, minphys, uio));
  284 }
  285 
  286 static int
  287 mdwrite(dev_t dev, struct uio *uio, int flags)
  288 {
  289         int unit;
  290         struct md_softc *sc;
  291 
  292         unit = MD_UNIT(dev);
  293 
  294         if (unit >= ramdisk_ndevs)
  295                 return ENXIO;
  296 
  297         sc = ramdisk_devs[unit];
  298 
  299         if (sc->sc_type == MD_UNCONFIGURED)
  300                 return ENXIO;
  301 
  302         return (physio(mdstrategy, NULL, dev, B_WRITE, minphys, uio));
  303 }
  304 
  305 /*
  306  * Handle I/O requests, either directly, or
  307  * by passing them to the server process.
  308  */
  309 static void
  310 mdstrategy(struct buf *bp)
  311 {
  312         int unit;
  313         struct md_softc *sc;
  314         caddr_t addr;
  315         size_t off, xfer;
  316 
  317         unit = MD_UNIT(bp->b_dev);
  318         sc = ramdisk_devs[unit];
  319 
  320         if (sc->sc_type == MD_UNCONFIGURED) {
  321                 bp->b_error = ENXIO;
  322                 bp->b_flags |= B_ERROR;
  323                 goto done;
  324         }
  325 
  326         switch (sc->sc_type) {
  327 #if MEMORY_DISK_SERVER
  328         case MD_UMEM_SERVER:
  329                 /* Just add this job to the server's queue. */
  330                 BUFQ_PUT(sc->sc_buflist, bp);
  331                 wakeup((caddr_t)sc);
  332                 /* see md_server_loop() */
  333                 /* no biodone in this case */
  334                 return;
  335 #endif  /* MEMORY_DISK_SERVER */
  336 
  337         case MD_KMEM_FIXED:
  338         case MD_KMEM_ALLOCATED:
  339                 /* These are in kernel space.  Access directly. */
  340                 bp->b_resid = bp->b_bcount;
  341                 off = (bp->b_blkno << DEV_BSHIFT);
  342                 if (off >= sc->sc_size) {
  343                         if (bp->b_flags & B_READ)
  344                                 break;  /* EOF */
  345                         goto set_eio;
  346                 }
  347                 xfer = bp->b_resid;
  348                 if (xfer > (sc->sc_size - off))
  349                         xfer = (sc->sc_size - off);
  350                 addr = sc->sc_addr + off;
  351                 if (bp->b_flags & B_READ)
  352                         memcpy(bp->b_data, addr, xfer);
  353                 else
  354                         memcpy(addr, bp->b_data, xfer);
  355                 bp->b_resid -= xfer;
  356                 break;
  357 
  358         default:
  359                 bp->b_resid = bp->b_bcount;
  360         set_eio:
  361                 bp->b_error = EIO;
  362                 bp->b_flags |= B_ERROR;
  363                 break;
  364         }
  365  done:
  366         biodone(bp);
  367 }
  368 
  369 static int
  370 mdioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct lwp *l)
  371 {
  372         int unit;
  373         struct md_softc *sc;
  374         struct md_conf *umd;
  375 
  376         unit = MD_UNIT(dev);
  377         sc = ramdisk_devs[unit];
  378 
  379         /* If this is not the raw partition, punt! */
  380         if (DISKPART(dev) != RAW_PART)
  381                 return ENOTTY;
  382 
  383         umd = (struct md_conf *)data;
  384         switch (cmd) {
  385         case MD_GETCONF:
  386                 *umd = sc->sc_md;
  387                 return 0;
  388 
  389         case MD_SETCONF:
  390                 /* Can only set it once. */
  391                 if (sc->sc_type != MD_UNCONFIGURED)
  392                         break;
  393                 switch (umd->md_type) {
  394                 case MD_KMEM_ALLOCATED:
  395                         return md_ioctl_kalloc(sc, umd, l);
  396 #if MEMORY_DISK_SERVER
  397                 case MD_UMEM_SERVER:
  398                         return md_ioctl_server(sc, umd, l);
  399 #endif  /* MEMORY_DISK_SERVER */
  400                 default:
  401                         break;
  402                 }
  403                 break;
  404         }
  405         return EINVAL;
  406 }
  407 
  408 /*
  409  * Handle ioctl MD_SETCONF for (sc_type == MD_KMEM_ALLOCATED)
  410  * Just allocate some kernel memory and return.
  411  */
  412 static int
  413 md_ioctl_kalloc(struct md_softc *sc, struct md_conf *umd,
  414     struct lwp *l)
  415 {
  416         vaddr_t addr;
  417         vsize_t size;
  418 
  419         /* Sanity check the size. */
  420         size = umd->md_size;
  421         addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO);
  422         if (!addr)
  423                 return ENOMEM;
  424 
  425         /* This unit is now configured. */
  426         sc->sc_addr = (caddr_t)addr;    /* kernel space */
  427         sc->sc_size = (size_t)size;
  428         sc->sc_type = MD_KMEM_ALLOCATED;
  429         return 0;
  430 }
  431 
  432 #if MEMORY_DISK_SERVER
  433 
  434 /*
  435  * Handle ioctl MD_SETCONF for (sc_type == MD_UMEM_SERVER)
  436  * Set config, then become the I/O server for this unit.
  437  */
  438 static int
  439 md_ioctl_server(struct md_softc *sc, struct md_conf *umd,
  440     struct lwp *l)
  441 {
  442         vaddr_t end;
  443         int error;
  444 
  445         /* Sanity check addr, size. */
  446         end = (vaddr_t) (umd->md_addr + umd->md_size);
  447 
  448         if ((end >= VM_MAXUSER_ADDRESS) ||
  449                 (end < ((vaddr_t) umd->md_addr)) )
  450                 return EINVAL;
  451 
  452         /* This unit is now configured. */
  453         sc->sc_addr = umd->md_addr;     /* user space */
  454         sc->sc_size = umd->md_size;
  455         sc->sc_type = MD_UMEM_SERVER;
  456 
  457         /* Become the server daemon */
  458         error = md_server_loop(sc);
  459 
  460         /* This server is now going away! */
  461         sc->sc_type = MD_UNCONFIGURED;
  462         sc->sc_addr = 0;
  463         sc->sc_size = 0;
  464 
  465         return (error);
  466 }
  467 
  468 static int md_sleep_pri = PWAIT | PCATCH;
  469 
  470 static int
  471 md_server_loop(struct md_softc *sc)
  472 {
  473         struct buf *bp;
  474         caddr_t addr;   /* user space address */
  475         size_t off;     /* offset into "device" */
  476         size_t xfer;    /* amount to transfer */
  477         int error;
  478 
  479         for (;;) {
  480                 /* Wait for some work to arrive. */
  481                 while ((bp = BUFQ_GET(sc->sc_buflist)) == NULL) {
  482                         error = tsleep((caddr_t)sc, md_sleep_pri, "md_idle", 0);
  483                         if (error)
  484                                 return error;
  485                 }
  486 
  487                 /* Do the transfer to/from user space. */
  488                 error = 0;
  489                 bp->b_resid = bp->b_bcount;
  490                 off = (bp->b_blkno << DEV_BSHIFT);
  491                 if (off >= sc->sc_size) {
  492                         if (bp->b_flags & B_READ)
  493                                 goto done;      /* EOF (not an error) */
  494                         error = EIO;
  495                         goto done;
  496                 }
  497                 xfer = bp->b_resid;
  498                 if (xfer > (sc->sc_size - off))
  499                         xfer = (sc->sc_size - off);
  500                 addr = sc->sc_addr + off;
  501                 if (bp->b_flags & B_READ)
  502                         error = copyin(addr, bp->b_data, xfer);
  503                 else
  504                         error = copyout(bp->b_data, addr, xfer);
  505                 if (!error)
  506                         bp->b_resid -= xfer;
  507 
  508         done:
  509                 if (error) {
  510                         bp->b_error = error;
  511                         bp->b_flags |= B_ERROR;
  512                 }
  513                 biodone(bp);
  514         }
  515 }
  516 #endif  /* MEMORY_DISK_SERVER */
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FreeBSD/Linux Kernel Cross Reference sys/dev/md.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/md.c
