kernel/blk_drv/blk.h

/* */
This source file includes following definitions.
end_request
   1 #ifndef _BLK_H
   2 #define _BLK_H
   3 
   4 #include <linux/sched.h>
   5 #include <linux/locks.h>
   6 #include <linux/genhd.h>
   7 
   8 /*
   9  * NR_REQUEST is the number of entries in the request-queue.
  10  * NOTE that writes may use only the low 2/3 of these: reads
  11  * take precedence.
  12  *
  13  * 32 seems to be a reasonable number: enough to get some benefit
  14  * from the elevator-mechanism, but not so much as to lock a lot of
  15  * buffers when they are in the queue. 64 seems to be too many (easily
  16  * long pauses in reading when heavy writing/syncing is going on)
  17  */
  18 #define NR_REQUEST      32
  19 
  20 /*
  21  * Ok, this is an expanded form so that we can use the same
  22  * request for paging requests when that is implemented. In
  23  * paging, 'bh' is NULL, and 'waiting' is used to wait for
  24  * read/write completion.
  25  */
  26 struct request {
  27         int dev;                /* -1 if no request */
  28         int cmd;                /* READ or WRITE */
  29         int errors;
  30         unsigned long sector;
  31         unsigned long nr_sectors;
  32         unsigned long current_nr_sectors;
  33         char * buffer;
  34         struct task_struct * waiting;
  35         struct buffer_head * bh;
  36         struct buffer_head * bhtail;
  37         struct request * next;
  38 };
  39 
  40 /*
  41  * This is used in the elevator algorithm: Note that
  42  * reads always go before writes. This is natural: reads
  43  * are much more time-critical than writes.
  44  */
  45 #define IN_ORDER(s1,s2) \
  46 ((s1)->cmd < (s2)->cmd || ((s1)->cmd == (s2)->cmd && \
  47 ((s1)->dev < (s2)->dev || (((s1)->dev == (s2)->dev && \
  48 (s1)->sector < (s2)->sector)))))
  49 
  50 struct blk_dev_struct {
  51         void (*request_fn)(void);
  52         struct request * current_request;
  53 };
  54 
  55 
  56 struct sec_size {
  57         unsigned block_size;
  58         unsigned block_size_bits;
  59 };
  60 
  61 /*
  62  * These will have to be changed to be aware of different buffer
  63  * sizes etc.. It actually needs a major cleanup.
  64  */
  65 #define SECTOR_MASK (blksize_size[MAJOR_NR] &&     \
  66         blksize_size[MAJOR_NR][MINOR(CURRENT->dev)] ? \
  67         ((blksize_size[MAJOR_NR][MINOR(CURRENT->dev)] >> 9) - 1) :  \
  68         ((BLOCK_SIZE >> 9)  -  1))
  69 
  70 #define SUBSECTOR(block) (CURRENT->current_nr_sectors > 0)
  71 
  72 extern struct sec_size * blk_sec[MAX_BLKDEV];
  73 extern struct blk_dev_struct blk_dev[MAX_BLKDEV];
  74 extern struct request request[NR_REQUEST];
  75 extern struct wait_queue * wait_for_request;
  76 extern void resetup_one_dev(struct gendisk *dev, int drive);
  77 
  78 extern int * blk_size[MAX_BLKDEV];
  79 
  80 extern int * blksize_size[MAX_BLKDEV];
  81 
  82 extern unsigned long hd_init(unsigned long mem_start, unsigned long mem_end);
  83 extern unsigned long cdu31a_init(unsigned long mem_start, unsigned long mem_end);
  84 extern unsigned long mcd_init(unsigned long mem_start, unsigned long mem_end);
  85 extern int is_read_only(int dev);
  86 extern void set_device_ro(int dev,int flag);
  87 
  88 extern void rd_load(void);
  89 extern long rd_init(long mem_start, int length);
  90 extern int ramdisk_size;
  91 
  92 extern unsigned long xd_init(unsigned long mem_start, unsigned long mem_end);
  93 
  94 #define RO_IOCTLS(dev,where) \
  95   case BLKROSET: if (!suser()) return -EPERM; \
  96                  set_device_ro((dev),get_fs_long((long *) (where))); return 0; \
  97   case BLKROGET: { int __err = verify_area(VERIFY_WRITE, (void *) (where), sizeof(long)); \
  98                    if (!__err) put_fs_long(is_read_only(dev),(long *) (where)); return __err; }
  99                  
 100 #ifdef MAJOR_NR
 101 
 102 /*
 103  * Add entries as needed. Currently the only block devices
 104  * supported are hard-disks and floppies.
 105  */
 106 
 107 #if (MAJOR_NR == 1)
 108 /* ram disk */
 109 #define DEVICE_NAME "ramdisk"
 110 #define DEVICE_REQUEST do_rd_request
 111 #define DEVICE_NR(device) ((device) & 7)
 112 #define DEVICE_ON(device) 
 113 #define DEVICE_OFF(device)
 114 
 115 #elif (MAJOR_NR == 2)
 116 /* floppy */
 117 static void floppy_on(unsigned int nr);
 118 static void floppy_off(unsigned int nr);
 119 
 120 #define DEVICE_NAME "floppy"
 121 #define DEVICE_INTR do_floppy
 122 #define DEVICE_REQUEST do_fd_request
 123 #define DEVICE_NR(device) ((device) & 3)
 124 #define DEVICE_ON(device) floppy_on(DEVICE_NR(device))
 125 #define DEVICE_OFF(device) floppy_off(DEVICE_NR(device))
 126 
 127 #elif (MAJOR_NR == 3)
 128 /* harddisk: timeout is 6 seconds.. */
 129 #define DEVICE_NAME "harddisk"
 130 #define DEVICE_INTR do_hd
 131 #define DEVICE_TIMEOUT HD_TIMER
 132 #define TIMEOUT_VALUE 600
 133 #define DEVICE_REQUEST do_hd_request
 134 #define DEVICE_NR(device) (MINOR(device)>>6)
 135 #define DEVICE_ON(device)
 136 #define DEVICE_OFF(device)
 137 
 138 #elif (MAJOR_NR == 8)
 139 /* scsi disk */
 140 #define DEVICE_NAME "scsidisk"
 141 #define DEVICE_INTR do_sd  
 142 #define TIMEOUT_VALUE 200
 143 #define DEVICE_REQUEST do_sd_request
 144 #define DEVICE_NR(device) (MINOR(device) >> 4)
 145 #define DEVICE_ON(device)
 146 #define DEVICE_OFF(device)
 147 
 148 #elif (MAJOR_NR == 9)
 149 /* scsi tape */
 150 #define DEVICE_NAME "scsitape"
 151 #define DEVICE_INTR do_st  
 152 #define DEVICE_REQUEST do_st_request
 153 #define DEVICE_NR(device) (MINOR(device))
 154 #define DEVICE_ON(device)
 155 #define DEVICE_OFF(device)
 156 
 157 #elif (MAJOR_NR == 11)
 158 /* scsi CD-ROM */
 159 #define DEVICE_NAME "CD-ROM"
 160 #define DEVICE_INTR do_sr
 161 #define DEVICE_REQUEST do_sr_request
 162 #define DEVICE_NR(device) (MINOR(device))
 163 #define DEVICE_ON(device)
 164 #define DEVICE_OFF(device)
 165 
 166 #elif (MAJOR_NR == 13)
 167 /* xt hard disk */
 168 #define DEVICE_NAME "xt disk"
 169 #define DEVICE_REQUEST do_xd_request
 170 #define DEVICE_NR(device) (MINOR(device) >> 6)
 171 #define DEVICE_ON(device)
 172 #define DEVICE_OFF(device)
 173 
 174 #elif (MAJOR_NR == 15)
 175 /* CDU31A CD-ROM */
 176 #define DEVICE_NAME "CDU31A"
 177 #define DEVICE_REQUEST do_cdu31a_request
 178 #define DEVICE_NR(device) (MINOR(device))
 179 #define DEVICE_ON(device)
 180 #define DEVICE_OFF(device)
 181 
 182 #elif (MAJOR_NR == 23)
 183 /* MITSUMI CD-ROM */
 184 #define DEVICE_NAME "Mitsumi CD-ROM"
 185 /* #define DEVICE_INTR do_mcd */
 186 #define DEVICE_REQUEST do_mcd_request
 187 #define DEVICE_NR(device) (MINOR(device))
 188 #define DEVICE_ON(device)
 189 #define DEVICE_OFF(device)
 190 
 191 #else
 192 /* unknown blk device */
 193 #error "unknown blk device"
 194 
 195 #endif
 196 
 197 #if (MAJOR_NR != 9)
 198 
 199 #ifndef CURRENT
 200 #define CURRENT (blk_dev[MAJOR_NR].current_request)
 201 #endif
 202 
 203 #define CURRENT_DEV DEVICE_NR(CURRENT->dev)
 204 
 205 #ifdef DEVICE_INTR
 206 void (*DEVICE_INTR)(void) = NULL;
 207 #endif
 208 #ifdef DEVICE_TIMEOUT
 209 
 210 #define SET_TIMER \
 211 ((timer_table[DEVICE_TIMEOUT].expires = jiffies + TIMEOUT_VALUE), \
 212 (timer_active |= 1<<DEVICE_TIMEOUT))
 213 
 214 #define CLEAR_TIMER \
 215 timer_active &= ~(1<<DEVICE_TIMEOUT)
 216 
 217 #define SET_INTR(x) \
 218 if ((DEVICE_INTR = (x)) != NULL) \
 219         SET_TIMER; \
 220 else \
 221         CLEAR_TIMER;
 222 
 223 #else
 224 
 225 #define SET_INTR(x) (DEVICE_INTR = (x))
 226 
 227 #endif
 228 static void (DEVICE_REQUEST)(void);
 229 
 230 /* SCSI devices have their own version */
 231 #if (MAJOR_NR != 8 && MAJOR_NR != 9 && MAJOR_NR != 11)
 232 static void end_request(int uptodate)
     /*  */
 233 {
 234         struct request * req;
 235         struct buffer_head * bh;
 236         struct task_struct * p;
 237 
 238         req = CURRENT;
 239         req->errors = 0;
 240         if (!uptodate) {
 241                 printk(DEVICE_NAME " I/O error\n");
 242                 printk("dev %04x, sector %d\n",req->dev,req->sector);
 243                 req->nr_sectors--;
 244                 req->nr_sectors &= ~SECTOR_MASK;
 245                 req->sector += (BLOCK_SIZE / 512);
 246                 req->sector &= ~SECTOR_MASK;            
 247         }
 248 
 249         if ((bh = req->bh) != NULL) {
 250                 req->bh = bh->b_reqnext;
 251                 bh->b_reqnext = NULL;
 252                 bh->b_uptodate = uptodate;
 253                 unlock_buffer(bh);
 254                 if ((bh = req->bh) != NULL) {
 255                         req->current_nr_sectors = bh->b_size >> 9;
 256                         if (req->nr_sectors < req->current_nr_sectors) {
 257                                 req->nr_sectors = req->current_nr_sectors;
 258                                 printk("end_request: buffer-list destroyed\n");
 259                         }
 260                         req->buffer = bh->b_data;
 261                         return;
 262                 }
 263         }
 264         DEVICE_OFF(req->dev);
 265         CURRENT = req->next;
 266         if ((p = req->waiting) != NULL) {
 267                 req->waiting = NULL;
 268                 p->state = TASK_RUNNING;
 269                 if (p->counter > current->counter)
 270                         need_resched = 1;
 271         }
 272         req->dev = -1;
 273         wake_up(&wait_for_request);
 274 }
 275 #endif
 276 
 277 #ifdef DEVICE_INTR
 278 #define CLEAR_INTR SET_INTR(NULL)
 279 #else
 280 #define CLEAR_INTR
 281 #endif
 282 
 283 #define INIT_REQUEST \
 284         if (!CURRENT) {\
 285                 CLEAR_INTR; \
 286                 return; \
 287         } \
 288         if (MAJOR(CURRENT->dev) != MAJOR_NR) \
 289                 panic(DEVICE_NAME ": request list destroyed"); \
 290         if (CURRENT->bh) { \
 291                 if (!CURRENT->bh->b_lock) \
 292                         panic(DEVICE_NAME ": block not locked"); \
 293         }
 294 
 295 #endif
 296 
 297 #endif
 298 #endif
/* */
root/kernel/blk_drv/blk.h

INCLUDED FROM

DEFINITIONS
