| #ifndef _BLK_H |
| #define _BLK_H |
| |
| #include <linux/fs.h> |
| #include <linux/locks.h> |
| |
| /* |
| * NR_REQUEST is the number of entries in the request-queue. |
| * NOTE that writes may use only the low 2/3 of these: reads |
| * take precedence. |
| * |
| * 32 seems to be a reasonable number: enough to get some benefit |
| * from the elevator-mechanism, but not so much as to lock a lot of |
| * buffers when they are in the queue. 64 seems to be too many (easily |
| * long pauses in reading when heavy writing/syncing is going on) |
| */ |
| #define NR_REQUEST 32 |
| |
| /* |
| * Ok, this is an expanded form so that we can use the same |
| * request for paging requests when that is implemented. In |
| * paging, 'bh' is NULL, and 'waiting' is used to wait for |
| * read/write completion. |
| */ |
| struct request { |
| int dev; /* -1 if no request */ |
| int cmd; /* READ or WRITE */ |
| int errors; |
| unsigned long sector; |
| unsigned long nr_sectors; |
| unsigned long current_nr_sectors; |
| char * buffer; |
| struct task_struct * waiting; |
| struct buffer_head * bh; |
| struct buffer_head * bhtail; |
| struct request * next; |
| }; |
| |
| /* |
| * This is used in the elevator algorithm: Note that |
| * reads always go before writes. This is natural: reads |
| * are much more time-critical than writes. |
| */ |
| #define IN_ORDER(s1,s2) \ |
| ((s1)->cmd < (s2)->cmd || ((s1)->cmd == (s2)->cmd && \ |
| ((s1)->dev < (s2)->dev || (((s1)->dev == (s2)->dev && \ |
| (s1)->sector < (s2)->sector))))) |
| |
| struct blk_dev_struct { |
| void (*request_fn)(void); |
| struct request * current_request; |
| }; |
| |
| |
| struct sec_size { |
| unsigned block_size; |
| unsigned block_size_bits; |
| }; |
| |
| /* |
| * These will have to be changed to be aware of different buffer |
| * sizes etc.. |
| */ |
| #define SECTOR_MASK ((1 << (BLOCK_SIZE_BITS - 9)) -1) |
| #define SUBSECTOR(block) ((block) & SECTOR_MASK) |
| |
| extern struct sec_size * blk_sec[MAX_BLKDEV]; |
| extern struct blk_dev_struct blk_dev[MAX_BLKDEV]; |
| extern struct request request[NR_REQUEST]; |
| extern struct wait_queue * wait_for_request; |
| |
| extern int * blk_size[MAX_BLKDEV]; |
| |
| extern unsigned long hd_init(unsigned long mem_start, unsigned long mem_end); |
| extern int is_read_only(int dev); |
| extern void set_device_ro(int dev,int flag); |
| |
| extern void rd_load(void); |
| extern long rd_init(long mem_start, int length); |
| extern int ramdisk_size; |
| |
| extern unsigned long xd_init(unsigned long mem_start, unsigned long mem_end); |
| |
| #define RO_IOCTLS(dev,where) \ |
| case BLKROSET: if (!suser()) return -EPERM; \ |
| set_device_ro((dev),get_fs_long((long *) (where))); return 0; \ |
| case BLKROGET: { int __err = verify_area(VERIFY_WRITE, (void *) (where), sizeof(long)); \ |
| if (!__err) put_fs_long(is_read_only(dev),(long *) (where)); return __err; } |
| |
| #ifdef MAJOR_NR |
| |
| /* |
| * Add entries as needed. Currently the only block devices |
| * supported are hard-disks and floppies. |
| */ |
| |
| #if (MAJOR_NR == 1) |
| /* ram disk */ |
| #define DEVICE_NAME "ramdisk" |
| #define DEVICE_REQUEST do_rd_request |
| #define DEVICE_NR(device) ((device) & 7) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #elif (MAJOR_NR == 2) |
| /* floppy */ |
| static void floppy_on(unsigned int nr); |
| static void floppy_off(unsigned int nr); |
| |
| #define DEVICE_NAME "floppy" |
| #define DEVICE_INTR do_floppy |
| #define DEVICE_REQUEST do_fd_request |
| #define DEVICE_NR(device) ((device) & 3) |
| #define DEVICE_ON(device) floppy_on(DEVICE_NR(device)) |
| #define DEVICE_OFF(device) floppy_off(DEVICE_NR(device)) |
| |
| #elif (MAJOR_NR == 3) |
| /* harddisk: timeout is 6 seconds.. */ |
| #define DEVICE_NAME "harddisk" |
| #define DEVICE_INTR do_hd |
| #define DEVICE_TIMEOUT HD_TIMER |
| #define TIMEOUT_VALUE 600 |
| #define DEVICE_REQUEST do_hd_request |
| #define DEVICE_NR(device) (MINOR(device)>>6) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #elif (MAJOR_NR == 8) |
| /* scsi disk */ |
| #define DEVICE_NAME "scsidisk" |
| #define DEVICE_INTR do_sd |
| #define TIMEOUT_VALUE 200 |
| #define DEVICE_REQUEST do_sd_request |
| #define DEVICE_NR(device) (MINOR(device) >> 4) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #elif (MAJOR_NR == 9) |
| /* scsi tape */ |
| #define DEVICE_NAME "scsitape" |
| #define DEVICE_INTR do_st |
| #define DEVICE_REQUEST do_st_request |
| #define DEVICE_NR(device) (MINOR(device)) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #elif (MAJOR_NR == 11) |
| /* scsi CD-ROM */ |
| #define DEVICE_NAME "CD-ROM" |
| #define DEVICE_INTR do_sr |
| #define DEVICE_REQUEST do_sr_request |
| #define DEVICE_NR(device) (MINOR(device)) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #elif (MAJOR_NR == 13) |
| /* xt hard disk */ |
| #define DEVICE_NAME "xt disk" |
| #define DEVICE_REQUEST do_xd_request |
| #define DEVICE_NR(device) (MINOR(device) >> 6) |
| #define DEVICE_ON(device) |
| #define DEVICE_OFF(device) |
| |
| #else |
| /* unknown blk device */ |
| #error "unknown blk device" |
| |
| #endif |
| |
| #if (MAJOR_NR != 9) |
| |
| #ifndef CURRENT |
| #define CURRENT (blk_dev[MAJOR_NR].current_request) |
| #endif |
| |
| #define CURRENT_DEV DEVICE_NR(CURRENT->dev) |
| |
| #ifdef DEVICE_INTR |
| void (*DEVICE_INTR)(void) = NULL; |
| #endif |
| #ifdef DEVICE_TIMEOUT |
| |
| #define SET_TIMER \ |
| ((timer_table[DEVICE_TIMEOUT].expires = jiffies + TIMEOUT_VALUE), \ |
| (timer_active |= 1<<DEVICE_TIMEOUT)) |
| |
| #define CLEAR_TIMER \ |
| timer_active &= ~(1<<DEVICE_TIMEOUT) |
| |
| #define SET_INTR(x) \ |
| if ((DEVICE_INTR = (x)) != NULL) \ |
| SET_TIMER; \ |
| else \ |
| CLEAR_TIMER; |
| |
| #else |
| |
| #define SET_INTR(x) (DEVICE_INTR = (x)) |
| |
| #endif |
| static void (DEVICE_REQUEST)(void); |
| |
| /* SCSI devices have their own version */ |
| #if (MAJOR_NR != 8 && MAJOR_NR != 9 && MAJOR_NR != 11) |
| static void end_request(int uptodate) |
| { |
| struct request * req; |
| struct buffer_head * bh; |
| struct task_struct * p; |
| |
| req = CURRENT; |
| req->errors = 0; |
| if (!uptodate) { |
| printk(DEVICE_NAME " I/O error\n"); |
| printk("dev %04x, sector %d\n",req->dev,req->sector); |
| req->nr_sectors--; |
| req->nr_sectors &= ~SECTOR_MASK; |
| req->sector += (BLOCK_SIZE / 512); |
| req->sector &= ~SECTOR_MASK; |
| } |
| |
| if ((bh = req->bh) != NULL) { |
| req->bh = bh->b_reqnext; |
| bh->b_reqnext = NULL; |
| bh->b_uptodate = uptodate; |
| unlock_buffer(bh); |
| if ((bh = req->bh) != NULL) { |
| req->current_nr_sectors = bh->b_size >> 9; |
| if (req->nr_sectors < req->current_nr_sectors) { |
| req->nr_sectors = req->current_nr_sectors; |
| printk("end_request: buffer-list destroyed\n"); |
| } |
| req->buffer = bh->b_data; |
| return; |
| } |
| } |
| DEVICE_OFF(req->dev); |
| CURRENT = req->next; |
| if ((p = req->waiting) != NULL) { |
| req->waiting = NULL; |
| p->state = TASK_RUNNING; |
| if (p->counter > current->counter) |
| need_resched = 1; |
| } |
| req->dev = -1; |
| wake_up(&wait_for_request); |
| } |
| #endif |
| |
| #ifdef DEVICE_INTR |
| #define CLEAR_INTR SET_INTR(NULL) |
| #else |
| #define CLEAR_INTR |
| #endif |
| |
| #define INIT_REQUEST \ |
| if (!CURRENT) {\ |
| CLEAR_INTR; \ |
| return; \ |
| } \ |
| if (MAJOR(CURRENT->dev) != MAJOR_NR) \ |
| panic(DEVICE_NAME ": request list destroyed"); \ |
| if (CURRENT->bh) { \ |
| if (!CURRENT->bh->b_lock) \ |
| panic(DEVICE_NAME ": block not locked"); \ |
| } |
| |
| #endif |
| |
| #endif |
| #endif |