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Annotation of linux/fs/block_dev.c, revision 1.1.1.7

1.1.1.2   root        1: /*
                      2:  *  linux/fs/block_dev.c
                      3:  *
1.1.1.7 ! root        4:  *  Copyright (C) 1991, 1992  Linus Torvalds
1.1.1.2   root        5:  */
                      6: 
1.1.1.7 ! root        7: #include <linux/errno.h>
1.1.1.2   root        8: #include <linux/sched.h>
1.1       root        9: #include <linux/kernel.h>
                     10: #include <asm/segment.h>
1.1.1.2   root       11: #include <asm/system.h>
1.1       root       12: 
1.1.1.3   root       13: extern int *blk_size[];
                     14: 
1.1.1.4   root       15: int block_write(struct inode * inode, struct file * filp, char * buf, int count)
1.1       root       16: {
1.1.1.4   root       17:        int block = filp->f_pos >> BLOCK_SIZE_BITS;
                     18:        int offset = filp->f_pos & (BLOCK_SIZE-1);
1.1       root       19:        int chars;
                     20:        int written = 0;
1.1.1.3   root       21:        int size;
1.1.1.4   root       22:        unsigned int dev;
1.1       root       23:        struct buffer_head * bh;
                     24:        register char * p;
                     25: 
1.1.1.4   root       26:        dev = inode->i_rdev;
1.1.1.3   root       27:        if (blk_size[MAJOR(dev)])
                     28:                size = blk_size[MAJOR(dev)][MINOR(dev)];
                     29:        else
                     30:                size = 0x7fffffff;
1.1       root       31:        while (count>0) {
1.1.1.3   root       32:                if (block >= size)
1.1.1.4   root       33:                        return written;
1.1.1.2   root       34:                chars = BLOCK_SIZE - offset;
                     35:                if (chars > count)
                     36:                        chars=count;
                     37:                if (chars == BLOCK_SIZE)
1.1.1.7 ! root       38:                        bh = getblk(dev, block, BLOCK_SIZE);
1.1.1.2   root       39:                else
                     40:                        bh = breada(dev,block,block+1,block+2,-1);
                     41:                block++;
1.1       root       42:                if (!bh)
                     43:                        return written?written:-EIO;
                     44:                p = offset + bh->b_data;
                     45:                offset = 0;
1.1.1.4   root       46:                filp->f_pos += chars;
1.1       root       47:                written += chars;
                     48:                count -= chars;
1.1.1.5   root       49:                memcpy_fromfs(p,buf,chars);
                     50:                p += chars;
                     51:                buf += chars;
1.1.1.6   root       52:                bh->b_uptodate = 1;
1.1       root       53:                bh->b_dirt = 1;
                     54:                brelse(bh);
                     55:        }
                     56:        return written;
                     57: }
                     58: 
1.1.1.4   root       59: int block_read(struct inode * inode, struct file * filp, char * buf, int count)
1.1       root       60: {
1.1.1.4   root       61:        unsigned int block = filp->f_pos >> BLOCK_SIZE_BITS;
                     62:        unsigned int offset = filp->f_pos & (BLOCK_SIZE-1);
                     63:        unsigned int chars;
                     64:        unsigned int size;
                     65:        unsigned int dev;
1.1       root       66:        int read = 0;
                     67:        struct buffer_head * bh;
                     68:        register char * p;
                     69: 
1.1.1.4   root       70:        dev = inode->i_rdev;
1.1.1.3   root       71:        if (blk_size[MAJOR(dev)])
                     72:                size = blk_size[MAJOR(dev)][MINOR(dev)];
                     73:        else
                     74:                size = 0x7fffffff;
1.1       root       75:        while (count>0) {
1.1.1.3   root       76:                if (block >= size)
1.1.1.4   root       77:                        return read;
1.1.1.2   root       78:                chars = BLOCK_SIZE-offset;
                     79:                if (chars > count)
                     80:                        chars = count;
                     81:                if (!(bh = breada(dev,block,block+1,block+2,-1)))
1.1       root       82:                        return read?read:-EIO;
1.1.1.2   root       83:                block++;
1.1       root       84:                p = offset + bh->b_data;
                     85:                offset = 0;
1.1.1.4   root       86:                filp->f_pos += chars;
1.1       root       87:                read += chars;
                     88:                count -= chars;
1.1.1.5   root       89:                memcpy_tofs(buf,p,chars);
                     90:                p += chars;
                     91:                buf += chars;
1.1       root       92:                brelse(bh);
                     93:        }
                     94:        return read;
                     95: }

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