drivers/scsi/sg.c

/* */
This source file includes following definitions.
sg_ioctl
sg_open
sg_close
sg_malloc
sg_free
sg_read
sg_command_done
sg_write
sg_detect
sg_init
sg_attach
   1 /*
   2    History:
   3     Started: Aug 9 by Lawrence Foard (entropy@world.std.com), to allow user 
   4      process control of SCSI devices.
   5     Development Sponsored by Killy Corp. NY NY
   6     
   7     Borrows code from st driver.
   8 */
   9 
  10 #include <linux/fs.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/string.h>
  14 #include <linux/errno.h>
  15 #include <linux/mtio.h>
  16 #include <linux/ioctl.h>
  17 #include <linux/fcntl.h>
  18 #include <asm/io.h>
  19 #include <asm/segment.h>
  20 #include <asm/system.h>
  21 
  22 #include "../block/blk.h"
  23 #include "scsi.h"
  24 #include "hosts.h"
  25 #include "scsi_ioctl.h"
  26 #include "sg.h"
  27 
  28 static void sg_init(void);
  29 static void sg_attach(Scsi_Device *);
  30 static int sg_detect(Scsi_Device *);
  31 
  32 
  33 struct Scsi_Device_Template sg_template = {NULL, NULL, "sg", 0xff, 
  34                                              SCSI_GENERIC_MAJOR, 0, 0, 0, 0,
  35                                              sg_detect, sg_init,
  36                                              NULL, sg_attach, NULL};
  37 
  38 #ifdef SG_BIG_BUFF
  39 static char *big_buff;
  40 static struct wait_queue *big_wait;   /* wait for buffer available */
  41 static int big_inuse=0;
  42 #endif
  43 
  44 struct scsi_generic
  45  {
  46   Scsi_Device *device;
  47   int users;   /* how many people have it open? */
  48   struct wait_queue *generic_wait; /* wait for device to be available */
  49   struct wait_queue *read_wait;    /* wait for response */
  50   struct wait_queue *write_wait;   /* wait for free buffer */
  51   int timeout; /* current default value for device */
  52   int buff_len; /* length of current buffer */
  53   char *buff;   /* the buffer */
  54   struct sg_header header; /* header of pending command */
  55   char exclude; /* opened for exclusive access */
  56   char pending;  /* don't accept writes now */
  57   char complete; /* command complete allow a read */
  58  };
  59 
  60 static struct scsi_generic *scsi_generics=NULL;
  61 static void sg_free(char *buff,int size);
  62 
  63 static int sg_ioctl(struct inode * inode,struct file * file,
     /*  */
  64              unsigned int cmd_in, unsigned long arg)
  65  {
  66   int dev = MINOR(inode->i_rdev);
  67   if ((dev<0) || (dev>=sg_template.dev_max))
  68    return -ENXIO;
  69   switch(cmd_in)
  70    {
  71     case SG_SET_TIMEOUT:
  72      scsi_generics[dev].timeout=get_fs_long((int *) arg);
  73      return 0;
  74     case SG_GET_TIMEOUT:
  75      return scsi_generics[dev].timeout;
  76     default:
  77      return scsi_ioctl(scsi_generics[dev].device, cmd_in, (void *) arg);
  78    }
  79  }
  80 
  81 static int sg_open(struct inode * inode, struct file * filp)
     /*  */
  82  {
  83   int dev=MINOR(inode->i_rdev);
  84   int flags=filp->f_flags;
  85   if (dev>=sg_template.dev_max || !scsi_generics[dev].device)
  86    return -ENXIO;
  87   if (O_RDWR!=(flags & O_ACCMODE))
  88    return -EACCES;
  89   if (flags & O_EXCL)
  90    {
  91     while(scsi_generics[dev].users)
  92      {
  93       if (flags & O_NONBLOCK)
  94        return -EBUSY;
  95       interruptible_sleep_on(&scsi_generics[dev].generic_wait);
  96       if (current->signal & ~current->blocked)
  97        return -ERESTARTSYS;
  98      }
  99     scsi_generics[dev].exclude=1;
 100    }
 101   else
 102    while(scsi_generics[dev].exclude)
 103     {
 104      if (flags & O_NONBLOCK)
 105       return -EBUSY;
 106      interruptible_sleep_on(&scsi_generics[dev].generic_wait);
 107      if (current->signal & ~current->blocked)
 108       return -ERESTARTSYS;
 109     }
 110   if (!scsi_generics[dev].users && scsi_generics[dev].pending && scsi_generics[dev].complete)
 111    {
 112     if (scsi_generics[dev].buff != NULL)
 113       sg_free(scsi_generics[dev].buff,scsi_generics[dev].buff_len);
 114     scsi_generics[dev].buff=NULL;
 115     scsi_generics[dev].pending=0;
 116    }
 117   if (!scsi_generics[dev].users)
 118    scsi_generics[dev].timeout=SG_DEFAULT_TIMEOUT;
 119   scsi_generics[dev].users++;
 120   return 0;
 121  }
 122 
 123 static void sg_close(struct inode * inode, struct file * filp)
     /*  */
 124  {
 125   int dev=MINOR(inode->i_rdev);
 126   scsi_generics[dev].users--;
 127   scsi_generics[dev].exclude=0;
 128   wake_up(&scsi_generics[dev].generic_wait);
 129  }
 130 
 131 static char *sg_malloc(int size)
     /*  */
 132  {
 133   if (size<=4096)
 134    return (char *) scsi_malloc(size);
 135 #ifdef SG_BIG_BUFF
 136   if (size<SG_BIG_BUFF)
 137    {
 138     while(big_inuse)
 139      {
 140       interruptible_sleep_on(&big_wait);
 141       if (current->signal & ~current->blocked)
 142        return NULL;
 143      }
 144     big_inuse=1;
 145     return big_buff;
 146    }
 147 #endif   
 148   return NULL;
 149  }
 150 
 151 static void sg_free(char *buff,int size) 
     /*  */
 152  {
 153 #ifdef SG_BIG_BUFF
 154   if (buff==big_buff)
 155    {
 156     big_inuse=0;
 157     wake_up(&big_wait);
 158     return;
 159    }
 160 #endif
 161   scsi_free(buff,size);
 162  }
 163 
 164 static int sg_read(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 165  {
 166   int dev=MINOR(inode->i_rdev);
 167   int i;
 168   struct scsi_generic *device=&scsi_generics[dev];
 169   if ((i=verify_area(VERIFY_WRITE,buf,count)))
 170    return i;
 171   while(!device->pending || !device->complete)
 172    {
 173     if (filp->f_flags & O_NONBLOCK)
 174      return -EWOULDBLOCK;
 175     interruptible_sleep_on(&device->read_wait);
 176     if (current->signal & ~current->blocked)
 177      return -ERESTARTSYS;
 178    }
 179   device->header.pack_len=device->header.reply_len;
 180   device->header.result=0;
 181   if (count>=sizeof(struct sg_header))
 182    {
 183     memcpy_tofs(buf,&device->header,sizeof(struct sg_header));
 184     buf+=sizeof(struct sg_header);
 185     if (count>device->header.pack_len)
 186      count=device->header.pack_len;
 187     if (count > sizeof(struct sg_header)) {
 188        memcpy_tofs(buf,device->buff,count-sizeof(struct sg_header));
 189     }
 190    }
 191   else
 192    count=0;
 193   sg_free(device->buff,device->buff_len);
 194   device->buff = NULL;
 195   device->pending=0;
 196   wake_up(&device->write_wait);
 197   return count;
 198  }
 199 
 200 static void sg_command_done(Scsi_Cmnd * SCpnt)
     /*  */
 201  {
 202   int dev=SCpnt->request.dev;
 203   struct scsi_generic *device=&scsi_generics[dev];
 204   if (!device->pending)
 205    {
 206     printk("unexpected done for sg %d\n",dev);
 207     SCpnt->request.dev=-1;
 208     return;
 209    }
 210   memcpy(device->header.sense_buffer, SCpnt->sense_buffer, sizeof(SCpnt->sense_buffer));
 211   if (SCpnt->sense_buffer[0])
 212    {
 213     device->header.result=EIO;
 214    }
 215   else
 216    device->header.result=SCpnt->result;
 217   device->complete=1;
 218   SCpnt->request.dev=-1;
 219   wake_up(&scsi_generics[dev].read_wait);
 220  }
 221 
 222 static int sg_write(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 223  {
 224   int dev=MINOR(inode->i_rdev);
 225   Scsi_Cmnd *SCpnt;
 226   int bsize,size,amt,i;
 227   unsigned char opcode;
 228   unsigned char cmnd[MAX_COMMAND_SIZE];
 229   struct scsi_generic *device=&scsi_generics[dev];
 230 
 231   if ((i=verify_area(VERIFY_READ,buf,count)))
 232    return i;
 233   if (count<sizeof(struct sg_header))
 234    return -EIO;
 235   /* make sure we can fit */
 236   while(device->pending)
 237    {
 238     if (filp->f_flags & O_NONBLOCK)
 239      return -EWOULDBLOCK;
 240 #ifdef DEBUG
 241     printk("sg_write: sleeping on pending request\n");
 242 #endif     
 243     interruptible_sleep_on(&device->write_wait);
 244     if (current->signal & ~current->blocked)
 245      return -ERESTARTSYS;
 246    }
 247   device->pending=1;
 248   device->complete=0;
 249   memcpy_fromfs(&device->header,buf,sizeof(struct sg_header));
 250   /* fix input size */
 251   device->header.pack_len=count;
 252   buf+=sizeof(struct sg_header);
 253   bsize=(device->header.pack_len>device->header.reply_len) ? device->header.pack_len : device->header.reply_len;
 254   bsize-=sizeof(struct sg_header);
 255   amt=bsize;
 256   if (!bsize)
 257    bsize++;
 258   bsize=(bsize+511) & ~511;
 259   if ((bsize<0) || !(device->buff=sg_malloc(device->buff_len=bsize)))
 260    {
 261     device->pending=0;
 262     wake_up(&device->write_wait);
 263     return -ENOMEM;
 264    }
 265 #ifdef DEBUG
 266   printk("allocating device\n");
 267 #endif
 268   if (!(SCpnt=allocate_device(NULL,device->device, !(filp->f_flags & O_NONBLOCK))))
 269    {
 270     device->pending=0;
 271     wake_up(&device->write_wait);
 272     sg_free(device->buff,device->buff_len);
 273     device->buff = NULL;
 274     return -EWOULDBLOCK;
 275    } 
 276 #ifdef DEBUG
 277   printk("device allocated\n");
 278 #endif    
 279   /* now issue command */
 280   SCpnt->request.dev=dev;
 281   SCpnt->sense_buffer[0]=0;
 282   opcode = get_fs_byte(buf);
 283   size=COMMAND_SIZE(opcode);
 284   if (opcode >= 0xc0 && device->header.twelve_byte) size = 12;
 285   SCpnt->cmd_len = size;
 286   memcpy_fromfs(cmnd,buf,size);
 287   buf+=size;
 288   memcpy_fromfs(device->buff,buf,device->header.pack_len-size-sizeof(struct sg_header));
 289   cmnd[1]=(cmnd[1] & 0x1f) | (device->device->lun<<5);
 290 #ifdef DEBUG
 291   printk("do cmd\n");
 292 #endif
 293   scsi_do_cmd (SCpnt,(void *) cmnd,
 294                (void *) device->buff,amt,sg_command_done,device->timeout,SG_DEFAULT_RETRIES);
 295 #ifdef DEBUG
 296   printk("done cmd\n");
 297 #endif               
 298   return count;
 299  }
 300 
 301 static struct file_operations sg_fops = {
 302    NULL,            /* lseek */
 303    sg_read,         /* read */
 304    sg_write,        /* write */
 305    NULL,            /* readdir */
 306    NULL,            /* select */
 307    sg_ioctl,        /* ioctl */
 308    NULL,            /* mmap */
 309    sg_open,         /* open */
 310    sg_close,        /* release */
 311    NULL             /* fsync */
 312 };
 313 
 314 
 315 static int sg_detect(Scsi_Device * SDp){
     /*  */
 316   /* We do not support attaching loadable devices yet. */
 317   if(scsi_loadable_module_flag) return 0;
 318 
 319   ++sg_template.dev_noticed;
 320   return 1;
 321 }
 322 
 323 /* Driver initialization */
 324 static void sg_init()
     /*  */
 325  {
 326    static int sg_registered = 0;
 327    
 328    if (sg_template.dev_noticed == 0) return;
 329 
 330    if(!sg_registered) {
 331      if (register_chrdev(SCSI_GENERIC_MAJOR,"sg",&sg_fops)) 
 332        {
 333          printk("Unable to get major %d for generic SCSI device\n",
 334                 SCSI_GENERIC_MAJOR);
 335          return;
 336        }
 337      sg_registered++;
 338    }
 339 
 340    /* We do not support attaching loadable devices yet. */
 341    if(scsi_loadable_module_flag) return;
 342 #ifdef DEBUG
 343   printk("sg: Init generic device.\n");
 344 #endif
 345 
 346 #ifdef SG_BIG_BUFF
 347   big_buff= (char *) scsi_init_malloc(SG_BIG_BUFF);
 348 #endif
 349 
 350    scsi_generics = (struct scsi_generic *) 
 351      scsi_init_malloc(sg_template.dev_noticed * sizeof(struct scsi_generic));
 352    memset(scsi_generics, 0, sg_template.dev_noticed * sizeof(struct scsi_generic));
 353 
 354    sg_template.dev_max = sg_template.dev_noticed;
 355  }
 356 
 357 static void sg_attach(Scsi_Device * SDp)
     /*  */
 358  {
 359    struct scsi_generic * gpnt;
 360    int i;
 361 
 362    /* We do not support attaching loadable devices yet. */
 363    if(scsi_loadable_module_flag) return;
 364 
 365    if(sg_template.nr_dev >= sg_template.dev_max) 
 366      panic ("scsi_devices corrupt (sg)");
 367 
 368    for(gpnt = scsi_generics, i=0; i<sg_template.dev_max; i++, gpnt++) 
 369      if(!gpnt->device) break;
 370 
 371    if(i >= sg_template.dev_max) panic ("scsi_devices corrupt (sg)");
 372 
 373    scsi_generics[i].device=SDp;
 374    scsi_generics[i].users=0;
 375    scsi_generics[i].generic_wait=NULL;
 376    scsi_generics[i].read_wait=NULL;
 377    scsi_generics[i].write_wait=NULL;
 378    scsi_generics[i].buff=NULL;
 379    scsi_generics[i].exclude=0;
 380    scsi_generics[i].pending=0;
 381    scsi_generics[i].timeout=SG_DEFAULT_TIMEOUT;
 382    sg_template.nr_dev++;
 383  };
/* */
root/drivers/scsi/sg.c

DEFINITIONS
