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     if (scsi_generics[dev].buff != NULL)
 112       scsi_free(scsi_generics[dev].buff,scsi_generics[dev].buff_len);
 113     scsi_generics[dev].buff=NULL;
 114     scsi_generics[dev].pending=0;
 115    }
 116   if (!scsi_generics[dev].users)
 117    scsi_generics[dev].timeout=SG_DEFAULT_TIMEOUT;
 118   scsi_generics[dev].users++;
 119   return 0;
 120  }
 121 
 122 static void sg_close(struct inode * inode, struct file * filp)
     /*  */
 123  {
 124   int dev=MINOR(inode->i_rdev);
 125   scsi_generics[dev].users--;
 126   scsi_generics[dev].exclude=0;
 127   wake_up(&scsi_generics[dev].generic_wait);
 128  }
 129 
 130 static char *sg_malloc(int size)
     /*  */
 131  {
 132   if (size<=4096)
 133    return (char *) scsi_malloc(size);
 134 #ifdef SG_BIG_BUFF
 135   if (size<SG_BIG_BUFF)
 136    {
 137     while(big_inuse)
 138      {
 139       interruptible_sleep_on(&big_wait);
 140       if (current->signal & ~current->blocked)
 141        return NULL;
 142      }
 143     big_inuse=1;
 144     return big_buff;
 145    }
 146 #endif   
 147   return NULL;
 148  }
 149 
 150 static void sg_free(char *buff,int size) 
     /*  */
 151  {
 152 #ifdef SG_BIG_BUFF
 153   if (buff==big_buff)
 154    {
 155     big_inuse=0;
 156     wake_up(&big_wait);
 157     return;
 158    }
 159 #endif
 160   scsi_free(buff,size);
 161  }
 162 
 163 static int sg_read(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 164  {
 165   int dev=MINOR(inode->i_rdev);
 166   int i;
 167   struct scsi_generic *device=&scsi_generics[dev];
 168   if ((i=verify_area(VERIFY_WRITE,buf,count)))
 169    return i;
 170   while(!device->pending || !device->complete)
 171    {
 172     if (filp->f_flags & O_NONBLOCK)
 173      return -EWOULDBLOCK;
 174     interruptible_sleep_on(&device->read_wait);
 175     if (current->signal & ~current->blocked)
 176      return -ERESTARTSYS;
 177    }
 178   device->header.pack_len=device->header.reply_len;
 179   device->header.result=0;
 180   if (count>=sizeof(struct sg_header))
 181    {
 182     memcpy_tofs(buf,&device->header,sizeof(struct sg_header));
 183     buf+=sizeof(struct sg_header);
 184     if (count>device->header.pack_len)
 185      count=device->header.pack_len;
 186     if (count > sizeof(struct sg_header)) {
 187        memcpy_tofs(buf,device->buff,count-sizeof(struct sg_header));
 188     }
 189    }
 190   else
 191    count=0;
 192   sg_free(device->buff,device->buff_len);
 193   device->buff = NULL;
 194   device->pending=0;
 195   wake_up(&device->write_wait);
 196   return count;
 197  }
 198 
 199 static void sg_command_done(Scsi_Cmnd * SCpnt)
     /*  */
 200  {
 201   int dev=SCpnt->request.dev;
 202   struct scsi_generic *device=&scsi_generics[dev];
 203   if (!device->pending)
 204    {
 205     printk("unexpected done for sg %d\n",dev);
 206     SCpnt->request.dev=-1;
 207     return;
 208    }
 209   memcpy(device->header.sense_buffer, SCpnt->sense_buffer, sizeof(SCpnt->sense_buffer));
 210   if (SCpnt->sense_buffer[0])
 211    {
 212     device->header.result=EIO;
 213    }
 214   else
 215    device->header.result=SCpnt->result;
 216   device->complete=1;
 217   SCpnt->request.dev=-1;
 218   wake_up(&scsi_generics[dev].read_wait);
 219  }
 220 
 221 static int sg_write(struct inode *inode,struct file *filp,char *buf,int count)
     /*  */
 222  {
 223   int dev=MINOR(inode->i_rdev);
 224   Scsi_Cmnd *SCpnt;
 225   int bsize,size,amt,i;
 226   unsigned char opcode;
 227   unsigned char cmnd[MAX_COMMAND_SIZE];
 228   struct scsi_generic *device=&scsi_generics[dev];
 229 
 230   if ((i=verify_area(VERIFY_READ,buf,count)))
 231    return i;
 232   if (count<sizeof(struct sg_header))
 233    return -EIO;
 234   /* make sure we can fit */
 235   while(device->pending)
 236    {
 237     if (filp->f_flags & O_NONBLOCK)
 238      return -EWOULDBLOCK;
 239 #ifdef DEBUG
 240     printk("sg_write: sleeping on pending request\n");
 241 #endif     
 242     interruptible_sleep_on(&device->write_wait);
 243     if (current->signal & ~current->blocked)
 244      return -ERESTARTSYS;
 245    }
 246   device->pending=1;
 247   device->complete=0;
 248   memcpy_fromfs(&device->header,buf,sizeof(struct sg_header));
 249   /* fix input size */
 250   device->header.pack_len=count;
 251   buf+=sizeof(struct sg_header);
 252   bsize=(device->header.pack_len>device->header.reply_len) ? device->header.pack_len : device->header.reply_len;
 253   bsize-=sizeof(struct sg_header);
 254   amt=bsize;
 255   if (!bsize)
 256    bsize++;
 257   bsize=(bsize+511) & ~511;
 258   if ((bsize<0) || !(device->buff=sg_malloc(device->buff_len=bsize)))
 259    {
 260     device->pending=0;
 261     wake_up(&device->write_wait);
 262     return -ENOMEM;
 263    }
 264 #ifdef DEBUG
 265   printk("allocating device\n");
 266 #endif
 267   if (!(SCpnt=allocate_device(NULL,device->device, !(filp->f_flags & O_NONBLOCK))))
 268    {
 269     device->pending=0;
 270     wake_up(&device->write_wait);
 271     sg_free(device->buff,device->buff_len);
 272     device->buff = NULL;
 273     return -EWOULDBLOCK;
 274    } 
 275 #ifdef DEBUG
 276   printk("device allocated\n");
 277 #endif    
 278   /* now issue command */
 279   SCpnt->request.dev=dev;
 280   SCpnt->sense_buffer[0]=0;
 281   opcode = get_fs_byte(buf);
 282   size=COMMAND_SIZE(opcode);
 283   if (opcode >= 0xc0 && device->header.twelve_byte) size = 12;
 284   SCpnt->cmd_len = size;
 285   memcpy_fromfs(cmnd,buf,size);
 286   buf+=size;
 287   memcpy_fromfs(device->buff,buf,device->header.pack_len-size-sizeof(struct sg_header));
 288   cmnd[1]=(cmnd[1] & 0x1f) | (device->device->lun<<5);
 289 #ifdef DEBUG
 290   printk("do cmd\n");
 291 #endif
 292   scsi_do_cmd (SCpnt,(void *) cmnd,
 293                (void *) device->buff,amt,sg_command_done,device->timeout,SG_DEFAULT_RETRIES);
 294 #ifdef DEBUG
 295   printk("done cmd\n");
 296 #endif               
 297   return count;
 298  }
 299 
 300 static struct file_operations sg_fops = {
 301    NULL,            /* lseek */
 302    sg_read,         /* read */
 303    sg_write,        /* write */
 304    NULL,            /* readdir */
 305    NULL,            /* select */
 306    sg_ioctl,        /* ioctl */
 307    NULL,            /* mmap */
 308    sg_open,         /* open */
 309    sg_close,        /* release */
 310    NULL             /* fsync */
 311 };
 312 
 313 
 314 static int sg_detect(Scsi_Device * SDp){
     /*  */
 315   /* We do not support attaching loadable devices yet. */
 316   if(scsi_loadable_module_flag) return 0;
 317 
 318   ++sg_template.dev_noticed;
 319   return 1;
 320 }
 321 
 322 /* Driver initialization */
 323 static void sg_init()
     /*  */
 324  {
 325    static int sg_registered = 0;
 326    
 327    if (sg_template.dev_noticed == 0) return;
 328 
 329    if(!sg_registered) {
 330      if (register_chrdev(SCSI_GENERIC_MAJOR,"sg",&sg_fops)) 
 331        {
 332          printk("Unable to get major %d for generic SCSI device\n",
 333                 SCSI_GENERIC_MAJOR);
 334          return;
 335        }
 336      sg_registered++;
 337    }
 338 
 339    /* We do not support attaching loadable devices yet. */
 340    if(scsi_loadable_module_flag) return;
 341 #ifdef DEBUG
 342   printk("sg: Init generic device.\n");
 343 #endif
 344 
 345 #ifdef SG_BIG_BUFF
 346   big_buff= (char *) scsi_init_malloc(SG_BIG_BUFF);
 347 #endif
 348 
 349    scsi_generics = (struct scsi_generic *) 
 350      scsi_init_malloc(sg_template.dev_noticed * sizeof(struct scsi_generic));
 351    memset(scsi_generics, 0, sg_template.dev_noticed * sizeof(struct scsi_generic));
 352 
 353    sg_template.dev_max = sg_template.dev_noticed;
 354  }
 355 
 356 static void sg_attach(Scsi_Device * SDp)
     /*  */
 357  {
 358    struct scsi_generic * gpnt;
 359    int i;
 360 
 361    /* We do not support attaching loadable devices yet. */
 362    if(scsi_loadable_module_flag) return;
 363 
 364    if(sg_template.nr_dev >= sg_template.dev_max) 
 365      panic ("scsi_devices corrupt (sg)");
 366 
 367    for(gpnt = scsi_generics, i=0; i<sg_template.dev_max; i++, gpnt++) 
 368      if(!gpnt->device) break;
 369 
 370    if(i >= sg_template.dev_max) panic ("scsi_devices corrupt (sg)");
 371 
 372    scsi_generics[i].device=SDp;
 373    scsi_generics[i].users=0;
 374    scsi_generics[i].generic_wait=NULL;
 375    scsi_generics[i].read_wait=NULL;
 376    scsi_generics[i].write_wait=NULL;
 377    scsi_generics[i].buff=NULL;
 378    scsi_generics[i].exclude=0;
 379    scsi_generics[i].pending=0;
 380    scsi_generics[i].timeout=SG_DEFAULT_TIMEOUT;
 381    sg_template.nr_dev++;
 382  };
/* */
root/drivers/scsi/sg.c

DEFINITIONS
