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 
  62 static int sg_ioctl(struct inode * inode,struct file * file,
     /*  */
  63              unsigned int cmd_in, unsigned long arg)
  64  {
  65   int dev = MINOR(inode->i_rdev);
  66   if ((dev<0) || (dev>=sg_template.dev_max))
  67    return -ENXIO;
  68   switch(cmd_in)
  69    {
  70     case SG_SET_TIMEOUT:
  71      scsi_generics[dev].timeout=get_fs_long((int *) arg);
  72      return 0;
  73     case SG_GET_TIMEOUT:
  74      return scsi_generics[dev].timeout;
  75     default:
  76      return scsi_ioctl(scsi_generics[dev].device, cmd_in, (void *) arg);
  77    }
  78  }
  79 
  80 static int sg_open(struct inode * inode, struct file * filp)
     /*  */
  81  {
  82   int dev=MINOR(inode->i_rdev);
  83   int flags=filp->f_flags;
  84   if (dev>=sg_template.dev_max || !scsi_generics[dev].device)
  85    return -ENXIO;
  86   if (O_RDWR!=(flags & O_ACCMODE))
  87    return -EACCES;
  88   if (flags & O_EXCL)
  89    {
  90     while(scsi_generics[dev].users)
  91      {
  92       if (flags & O_NONBLOCK)
  93        return -EBUSY;
  94       interruptible_sleep_on(&scsi_generics[dev].generic_wait);
  95       if (current->signal & ~current->blocked)
  96        return -ERESTARTSYS;
  97      }
  98     scsi_generics[dev].exclude=1;
  99    }
 100   else
 101    while(scsi_generics[dev].exclude)
 102     {
 103      if (flags & O_NONBLOCK)
 104       return -EBUSY;
 105      interruptible_sleep_on(&scsi_generics[dev].generic_wait);
 106      if (current->signal & ~current->blocked)
 107       return -ERESTARTSYS;
 108     }
 109   if (!scsi_generics[dev].users && scsi_generics[dev].pending && scsi_generics[dev].complete)
 110    {
 111     scsi_free(scsi_generics[dev].buff,scsi_generics[dev].buff_len);
 112     scsi_generics[dev].pending=0;
 113    }
 114   if (!scsi_generics[dev].users)
 115    scsi_generics[dev].timeout=SG_DEFAULT_TIMEOUT;
 116   scsi_generics[dev].users++;
 117   return 0;
 118  }
 119 
 120 static void sg_close(struct inode * inode, struct file * filp)
     /*  */
 121  {
 122   int dev=MINOR(inode->i_rdev);
 123   scsi_generics[dev].users--;
 124   scsi_generics[dev].exclude=0;
 125   wake_up(&scsi_generics[dev].generic_wait);
 126  }
 127 
 128 static char *sg_malloc(int size)
     /*  */
 129  {
 130   if (size<=4096)
 131    return (char *) scsi_malloc(size);
 132 #ifdef SG_BIG_BUFF
 133   if (size<SG_BIG_BUFF)
 134    {
 135     while(big_inuse)
 136      {
 137       interruptible_sleep_on(&big_wait);
 138       if (current->signal & ~current->blocked)
 139        return NULL;
 140      }
 141     big_inuse=1;
 142     return big_buff;
 143    }
 144 #endif   
 145   return NULL;
 146  }
 147 
 148 static void sg_free(char *buff,int size) 
     /*  */
 149  {
 150 #ifdef SG_BIG_BUFF
 151   if (buff==big_buff)
 152    {
 153     big_inuse=0;
 154     wake_up(&big_wait);
 155     return;
 156    }
 157 #endif
 158   scsi_free(buff,size);
 159  }
 160 
 161 static int sg_read(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 162  {
 163   int dev=MINOR(inode->i_rdev);
 164   int i;
 165   struct scsi_generic *device=&scsi_generics[dev];
 166   if ((i=verify_area(VERIFY_WRITE,buf,count)))
 167    return i;
 168   while(!device->pending || !device->complete)
 169    {
 170     if (filp->f_flags & O_NONBLOCK)
 171      return -EWOULDBLOCK;
 172     interruptible_sleep_on(&device->read_wait);
 173     if (current->signal & ~current->blocked)
 174      return -ERESTARTSYS;
 175    }
 176   device->header.pack_len=device->header.reply_len;
 177   device->header.result=0;
 178   if (count>=sizeof(struct sg_header))
 179    {
 180     memcpy_tofs(buf,&device->header,sizeof(struct sg_header));
 181     buf+=sizeof(struct sg_header);
 182     if (count>device->header.pack_len)
 183      count=device->header.pack_len;
 184     if (count > sizeof(struct sg_header)) {
 185        memcpy_tofs(buf,device->buff,count-sizeof(struct sg_header));
 186     }
 187    }
 188   else
 189    count=0;
 190   sg_free(device->buff,device->buff_len);
 191   device->pending=0;
 192   wake_up(&device->write_wait);
 193   return count;
 194  }
 195 
 196 static void sg_command_done(Scsi_Cmnd * SCpnt)
     /*  */
 197  {
 198   int dev=SCpnt->request.dev;
 199   struct scsi_generic *device=&scsi_generics[dev];
 200   if (!device->pending)
 201    {
 202     printk("unexpected done for sg %d\n",dev);
 203     SCpnt->request.dev=-1;
 204     return;
 205    }
 206   memcpy(device->header.sense_buffer, SCpnt->sense_buffer, sizeof(SCpnt->sense_buffer));
 207   if (SCpnt->sense_buffer[0])
 208    {
 209     device->header.result=EIO;
 210    }
 211   else
 212    device->header.result=SCpnt->result;
 213   device->complete=1;
 214   SCpnt->request.dev=-1;
 215   wake_up(&scsi_generics[dev].read_wait);
 216  }
 217 
 218 static int sg_write(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 219  {
 220   int dev=MINOR(inode->i_rdev);
 221   Scsi_Cmnd *SCpnt;
 222   int bsize,size,amt,i;
 223   unsigned char cmnd[MAX_COMMAND_SIZE];
 224   struct scsi_generic *device=&scsi_generics[dev];
 225 
 226   if ((i=verify_area(VERIFY_READ,buf,count)))
 227    return i;
 228   if (count<sizeof(struct sg_header))
 229    return -EIO;
 230   /* make sure we can fit */
 231   while(device->pending)
 232    {
 233     if (filp->f_flags & O_NONBLOCK)
 234      return -EWOULDBLOCK;
 235 #ifdef DEBUG
 236     printk("sg_write: sleeping on pending request\n");
 237 #endif     
 238     interruptible_sleep_on(&device->write_wait);
 239     if (current->signal & ~current->blocked)
 240      return -ERESTARTSYS;
 241    }
 242   device->pending=1;
 243   device->complete=0;
 244   memcpy_fromfs(&device->header,buf,sizeof(struct sg_header));
 245   /* fix input size */
 246   device->header.pack_len=count;
 247   buf+=sizeof(struct sg_header);
 248   bsize=(device->header.pack_len>device->header.reply_len) ? device->header.pack_len : device->header.reply_len;
 249   bsize-=sizeof(struct sg_header);
 250   amt=bsize;
 251   if (!bsize)
 252    bsize++;
 253   bsize=(bsize+511) & ~511;
 254   if ((bsize<0) || !(device->buff=sg_malloc(device->buff_len=bsize)))
 255    {
 256     device->pending=0;
 257     wake_up(&device->write_wait);
 258     return -ENOMEM;
 259    }
 260 #ifdef DEBUG
 261   printk("allocating device\n");
 262 #endif
 263   if (!(SCpnt=allocate_device(NULL,device->device, !(filp->f_flags & O_NONBLOCK))))
 264    {
 265     device->pending=0;
 266     wake_up(&device->write_wait);
 267     sg_free(device->buff,device->buff_len);
 268     return -EWOULDBLOCK;
 269    } 
 270 #ifdef DEBUG
 271   printk("device allocated\n");
 272 #endif    
 273   /* now issue command */
 274   SCpnt->request.dev=dev;
 275   SCpnt->sense_buffer[0]=0;
 276   size=COMMAND_SIZE(get_fs_byte(buf));
 277   memcpy_fromfs(cmnd,buf,size);
 278   buf+=size;
 279   memcpy_fromfs(device->buff,buf,device->header.pack_len-size-sizeof(struct sg_header));
 280   cmnd[1]=(cmnd[1] & 0x1f) | (device->device->lun<<5);
 281 #ifdef DEBUG
 282   printk("do cmd\n");
 283 #endif
 284   scsi_do_cmd (SCpnt,(void *) cmnd,
 285                (void *) device->buff,amt,sg_command_done,device->timeout,SG_DEFAULT_RETRIES);
 286 #ifdef DEBUG
 287   printk("done cmd\n");
 288 #endif               
 289   return count;
 290  }
 291 
 292 static struct file_operations sg_fops = {
 293    NULL,            /* lseek */
 294    sg_read,         /* read */
 295    sg_write,        /* write */
 296    NULL,            /* readdir */
 297    NULL,            /* select */
 298    sg_ioctl,        /* ioctl */
 299    NULL,            /* mmap */
 300    sg_open,         /* open */
 301    sg_close,        /* release */
 302    NULL             /* fsync */
 303 };
 304 
 305 
 306 static int sg_detect(Scsi_Device * SDp){
     /*  */
 307   /* We do not support attaching loadable devices yet. */
 308   if(scsi_loadable_module_flag) return 0;
 309 
 310   ++sg_template.dev_noticed;
 311   return 1;
 312 }
 313 
 314 /* Driver initialization */
 315 static void sg_init()
     /*  */
 316  {
 317    static int sg_registered = 0;
 318    
 319    if (sg_template.dev_noticed == 0) return;
 320 
 321    if(!sg_registered) {
 322      if (register_chrdev(SCSI_GENERIC_MAJOR,"sg",&sg_fops)) 
 323        {
 324          printk("Unable to get major %d for generic SCSI device\n",
 325                 SCSI_GENERIC_MAJOR);
 326          return;
 327        }
 328      sg_registered++;
 329    }
 330 
 331    /* We do not support attaching loadable devices yet. */
 332    if(scsi_loadable_module_flag) return;
 333 #ifdef DEBUG
 334   printk("sg: Init generic device.\n");
 335 #endif
 336 
 337 #ifdef SG_BIG_BUFF
 338   big_buff= (char *) scsi_init_malloc(SG_BIG_BUFF);
 339 #endif
 340 
 341    scsi_generics = (struct scsi_generic *) 
 342      scsi_init_malloc(sg_template.dev_noticed * sizeof(struct scsi_generic));
 343    memset(scsi_generics, 0, sg_template.dev_noticed * sizeof(struct scsi_generic));
 344 
 345    sg_template.dev_max = sg_template.dev_noticed;
 346  }
 347 
 348 static void sg_attach(Scsi_Device * SDp)
     /*  */
 349  {
 350    struct scsi_generic * gpnt;
 351    int i;
 352 
 353    /* We do not support attaching loadable devices yet. */
 354    if(scsi_loadable_module_flag) return;
 355 
 356    if(sg_template.nr_dev >= sg_template.dev_max) 
 357      panic ("scsi_devices corrupt (sg)");
 358 
 359    for(gpnt = scsi_generics, i=0; i<sg_template.dev_max; i++, gpnt++) 
 360      if(!gpnt->device) break;
 361 
 362    if(i >= sg_template.dev_max) panic ("scsi_devices corrupt (sg)");
 363 
 364    scsi_generics[i].device=SDp;
 365    scsi_generics[i].users=0;
 366    scsi_generics[i].generic_wait=NULL;
 367    scsi_generics[i].read_wait=NULL;
 368    scsi_generics[i].write_wait=NULL;
 369    scsi_generics[i].exclude=0;
 370    scsi_generics[i].pending=0;
 371    scsi_generics[i].timeout=SG_DEFAULT_TIMEOUT;
 372    sg_template.nr_dev++;
 373  };
/* */
root/drivers/scsi/sg.c

DEFINITIONS
