drivers/block/blk.h

/* */
This source file includes following definitions.
end_request
   1 #ifndef _BLK_H
   2 #define _BLK_H
   3 
   4 #include <linux/major.h>
   5 #include <linux/sched.h>
   6 #include <linux/locks.h>
   7 #include <linux/genhd.h>
   8 
   9 /*
  10  * NR_REQUEST is the number of entries in the request-queue.
  11  * NOTE that writes may use only the low 2/3 of these: reads
  12  * take precedence.
  13  *
  14  * 32 seems to be a reasonable number: enough to get some benefit
  15  * from the elevator-mechanism, but not so much as to lock a lot of
  16  * buffers when they are in the queue. 64 seems to be too many (easily
  17  * long pauses in reading when heavy writing/syncing is going on)
  18  */
  19 #define NR_REQUEST      64
  20 
  21 /*
  22  * Ok, this is an expanded form so that we can use the same
  23  * request for paging requests when that is implemented. In
  24  * paging, 'bh' is NULL, and 'waiting' is used to wait for
  25  * read/write completion.
  26  */
  27 struct request {
  28         int dev;                /* -1 if no request */
  29         int cmd;                /* READ or WRITE */
  30         int errors;
  31         unsigned long sector;
  32         unsigned long nr_sectors;
  33         unsigned long current_nr_sectors;
  34         char * buffer;
  35         struct task_struct * waiting;
  36         struct buffer_head * bh;
  37         struct buffer_head * bhtail;
  38         struct request * next;
  39 };
  40 
  41 /*
  42  * This is used in the elevator algorithm: Note that
  43  * reads always go before writes. This is natural: reads
  44  * are much more time-critical than writes.
  45  */
  46 #define IN_ORDER(s1,s2) \
  47 ((s1)->cmd < (s2)->cmd || ((s1)->cmd == (s2)->cmd && \
  48 ((s1)->dev < (s2)->dev || (((s1)->dev == (s2)->dev && \
  49 (s1)->sector < (s2)->sector)))))
  50 
  51 struct blk_dev_struct {
  52         void (*request_fn)(void);
  53         struct request * current_request;
  54 };
  55 
  56 
  57 struct sec_size {
  58         unsigned block_size;
  59         unsigned block_size_bits;
  60 };
  61 
  62 /*
  63  * These will have to be changed to be aware of different buffer
  64  * sizes etc.. It actually needs a major cleanup.
  65  */
  66 #define SECTOR_MASK (blksize_size[MAJOR_NR] &&     \
  67         blksize_size[MAJOR_NR][MINOR(CURRENT->dev)] ? \
  68         ((blksize_size[MAJOR_NR][MINOR(CURRENT->dev)] >> 9) - 1) :  \
  69         ((BLOCK_SIZE >> 9)  -  1))
  70 
  71 #define SUBSECTOR(block) (CURRENT->current_nr_sectors > 0)
  72 
  73 extern struct sec_size * blk_sec[MAX_BLKDEV];
  74 extern struct blk_dev_struct blk_dev[MAX_BLKDEV];
  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 == MEM_MAJOR)
 108 
 109 /* ram disk */
 110 #define DEVICE_NAME "ramdisk"
 111 #define DEVICE_REQUEST do_rd_request
 112 #define DEVICE_NR(device) ((device) & 7)
 113 #define DEVICE_ON(device) 
 114 #define DEVICE_OFF(device)
 115 
 116 #elif (MAJOR_NR == FLOPPY_MAJOR)
 117 
 118 static void floppy_on(unsigned int nr);
 119 static void floppy_off(unsigned int nr);
 120 
 121 #define DEVICE_NAME "floppy"
 122 #define DEVICE_INTR do_floppy
 123 #define DEVICE_REQUEST do_fd_request
 124 #define DEVICE_NR(device) ((device) & 3)
 125 #define DEVICE_ON(device) floppy_on(DEVICE_NR(device))
 126 #define DEVICE_OFF(device) floppy_off(DEVICE_NR(device))
 127 
 128 #elif (MAJOR_NR == HD_MAJOR)
 129 
 130 /* harddisk: timeout is 6 seconds.. */
 131 #define DEVICE_NAME "harddisk"
 132 #define DEVICE_INTR do_hd
 133 #define DEVICE_TIMEOUT HD_TIMER
 134 #define TIMEOUT_VALUE 600
 135 #define DEVICE_REQUEST do_hd_request
 136 #define DEVICE_NR(device) (MINOR(device)>>6)
 137 #define DEVICE_ON(device)
 138 #define DEVICE_OFF(device)
 139 
 140 #elif (MAJOR_NR == SCSI_DISK_MAJOR)
 141 
 142 #define DEVICE_NAME "scsidisk"
 143 #define DEVICE_INTR do_sd  
 144 #define TIMEOUT_VALUE 200
 145 #define DEVICE_REQUEST do_sd_request
 146 #define DEVICE_NR(device) (MINOR(device) >> 4)
 147 #define DEVICE_ON(device)
 148 #define DEVICE_OFF(device)
 149 
 150 #elif (MAJOR_NR == SCSI_TAPE_MAJOR)
 151 
 152 #define DEVICE_NAME "scsitape"
 153 #define DEVICE_INTR do_st  
 154 #define DEVICE_NR(device) (MINOR(device))
 155 #define DEVICE_ON(device)
 156 #define DEVICE_OFF(device)
 157 
 158 #elif (MAJOR_NR == SCSI_CDROM_MAJOR)
 159 
 160 #define DEVICE_NAME "CD-ROM"
 161 #define DEVICE_INTR do_sr
 162 #define DEVICE_REQUEST do_sr_request
 163 #define DEVICE_NR(device) (MINOR(device))
 164 #define DEVICE_ON(device)
 165 #define DEVICE_OFF(device)
 166 
 167 #elif (MAJOR_NR == XT_DISK_MAJOR)
 168 
 169 #define DEVICE_NAME "xt disk"
 170 #define DEVICE_REQUEST do_xd_request
 171 #define DEVICE_NR(device) (MINOR(device) >> 6)
 172 #define DEVICE_ON(device)
 173 #define DEVICE_OFF(device)
 174 
 175 #elif (MAJOR_NR == CDU31A_CDROM_MAJOR)
 176 
 177 #define DEVICE_NAME "CDU31A"
 178 #define DEVICE_REQUEST do_cdu31a_request
 179 #define DEVICE_NR(device) (MINOR(device))
 180 #define DEVICE_ON(device)
 181 #define DEVICE_OFF(device)
 182 
 183 #elif (MAJOR_NR == MITSUMI_CDROM_MAJOR)
 184 
 185 #define DEVICE_NAME "Mitsumi CD-ROM"
 186 /* #define DEVICE_INTR do_mcd */
 187 #define DEVICE_REQUEST do_mcd_request
 188 #define DEVICE_NR(device) (MINOR(device))
 189 #define DEVICE_ON(device)
 190 #define DEVICE_OFF(device)
 191 
 192 #elif (MAJOR_NR == MATSUSHITA_CDROM_MAJOR)
 193 
 194 #define DEVICE_NAME "Matsushita CD-ROM"
 195 #define DEVICE_REQUEST do_sbpcd_request
 196 #define DEVICE_NR(device) (MINOR(device))
 197 #define DEVICE_ON(device)
 198 #define DEVICE_OFF(device)
 199 
 200 #else
 201 
 202 #error "unknown blk device"
 203 
 204 #endif
 205 
 206 #if (MAJOR_NR != SCSI_TAPE_MAJOR)
 207 
 208 #ifndef CURRENT
 209 #define CURRENT (blk_dev[MAJOR_NR].current_request)
 210 #endif
 211 
 212 #define CURRENT_DEV DEVICE_NR(CURRENT->dev)
 213 
 214 #ifdef DEVICE_INTR
 215 void (*DEVICE_INTR)(void) = NULL;
 216 #endif
 217 #ifdef DEVICE_TIMEOUT
 218 
 219 #define SET_TIMER \
 220 ((timer_table[DEVICE_TIMEOUT].expires = jiffies + TIMEOUT_VALUE), \
 221 (timer_active |= 1<<DEVICE_TIMEOUT))
 222 
 223 #define CLEAR_TIMER \
 224 timer_active &= ~(1<<DEVICE_TIMEOUT)
 225 
 226 #define SET_INTR(x) \
 227 if ((DEVICE_INTR = (x)) != NULL) \
 228         SET_TIMER; \
 229 else \
 230         CLEAR_TIMER;
 231 
 232 #else
 233 
 234 #define SET_INTR(x) (DEVICE_INTR = (x))
 235 
 236 #endif
 237 static void (DEVICE_REQUEST)(void);
 238 
 239 /* end_request() - SCSI devices have their own version */
 240 
 241 #if ! SCSI_MAJOR(MAJOR_NR)
 242 
 243 static void end_request(int uptodate)
     /*  */
 244 {
 245         struct request * req;
 246         struct buffer_head * bh;
 247         struct task_struct * p;
 248 
 249         req = CURRENT;
 250         req->errors = 0;
 251         if (!uptodate) {
 252                 printk(DEVICE_NAME " I/O error\n");
 253                 printk("dev %04lX, sector %lu\n",
 254                        (unsigned long)req->dev, req->sector);
 255                 req->nr_sectors--;
 256                 req->nr_sectors &= ~SECTOR_MASK;
 257                 req->sector += (BLOCK_SIZE / 512);
 258                 req->sector &= ~SECTOR_MASK;            
 259         }
 260 
 261         if ((bh = req->bh) != NULL) {
 262                 req->bh = bh->b_reqnext;
 263                 bh->b_reqnext = NULL;
 264                 bh->b_uptodate = uptodate;
 265                 unlock_buffer(bh);
 266                 if ((bh = req->bh) != NULL) {
 267                         req->current_nr_sectors = bh->b_size >> 9;
 268                         if (req->nr_sectors < req->current_nr_sectors) {
 269                                 req->nr_sectors = req->current_nr_sectors;
 270                                 printk("end_request: buffer-list destroyed\n");
 271                         }
 272                         req->buffer = bh->b_data;
 273                         return;
 274                 }
 275         }
 276         DEVICE_OFF(req->dev);
 277         CURRENT = req->next;
 278         if ((p = req->waiting) != NULL) {
 279                 req->waiting = NULL;
 280                 p->state = TASK_RUNNING;
 281                 if (p->counter > current->counter)
 282                         need_resched = 1;
 283         }
 284         req->dev = -1;
 285         wake_up(&wait_for_request);
 286 }
 287 #endif
 288 
 289 #ifdef DEVICE_INTR
 290 #define CLEAR_INTR SET_INTR(NULL)
 291 #else
 292 #define CLEAR_INTR
 293 #endif
 294 
 295 #define INIT_REQUEST \
 296         if (!CURRENT) {\
 297                 CLEAR_INTR; \
 298                 return; \
 299         } \
 300         if (MAJOR(CURRENT->dev) != MAJOR_NR) \
 301                 panic(DEVICE_NAME ": request list destroyed"); \
 302         if (CURRENT->bh) { \
 303                 if (!CURRENT->bh->b_lock) \
 304                         panic(DEVICE_NAME ": block not locked"); \
 305         }
 306 
 307 #endif
 308 
 309 #endif
 310 #endif
/* */
root/drivers/block/blk.h

INCLUDED FROM

DEFINITIONS
