static int trd_make_request(request_queue_t *q, int rw, struct buffer_head *bh)
{
u_long start, len;
char *b_addr;
void *addr;
u_long minor, page, ofs, len1;
start = bh->b_rsector << 9;
minor = MINOR(bh->b_rdev);
len = bh->b_size;
if (!trd_base[minor]) {
int ret;
printk(KERN_ERR DEVICE_NAME ": access to unopened device minor=%ld\n", minor);
ret = trd_allocate(minor);
if (ret != 0) return ret;
}
if (minor >= MAX_DEVS || !trd_base[minor]) {
printk(KERN_ERR DEVICE_NAME ": bad minor %ld\n", minor);
goto io_error;
}
if (start + bh->b_size > TRD_SIZE) {
printk(KERN_ERR DEVICE_NAME ": bad access: block=%ld, count=%d\n",
bh->b_rsector, bh->b_size);
goto io_error;
}
if (rw == READA) rw = READ;
if ((rw != READ) && (rw != WRITE)) {
printk(KERN_ERR DEVICE_NAME ": bad command: %d\n", rw);
goto io_error;
}
b_addr = bh_kmap(bh);
while (len) {
page = start >> PAGE_SHIFT;
ofs = start & (PAGE_SIZE-1);
addr = (void *) (((char *)(trd_base[minor][page])) + ofs);
len1 = len;
if (ofs + len1 > PAGE_SIZE) {
len1 = PAGE_SIZE - ofs;
}
if (rw == READ) {
memcpy(b_addr, (char *)addr, len1);
} else {
memcpy((char *)addr, b_addr, len1);
}
len -= len1;
start += len1;
b_addr += len1;
}
bh_kunmap(bh);
bh->b_end_io(bh,1);
return 0;
io_error:
buffer_IO_error(bh);
return 0;
}
static int rd_blkdev_pagecache_IO(int rw, struct buffer_head * sbh, int minor)
{
struct address_space * mapping;
unsigned long index;
int offset, size, err;
err = -EIO;
err = 0;
mapping = rd_bdev[minor]->bd_inode->i_mapping;
index = sbh->b_rsector >> (PAGE_CACHE_SHIFT - 9);
offset = (sbh->b_rsector << 9) & ~PAGE_CACHE_MASK;
size = sbh->b_size;
do {
int count;
struct page ** hash;
struct page * page;
char * src, * dst;
int unlock = 0;
count = PAGE_CACHE_SIZE - offset;
if (count > size)
count = size;
size -= count;
hash = page_hash(mapping, index);
page = __find_get_page(mapping, index, hash);
if (!page) {
page = grab_cache_page(mapping, index);
err = -ENOMEM;
if (!page)
goto out;
err = 0;
if (!Page_Uptodate(page)) {
memset(kmap(page), 0, PAGE_CACHE_SIZE);
kunmap(page);
SetPageUptodate(page);
}
unlock = 1;
}
index++;
if (rw == READ) {
src = kmap(page);
src += offset;
dst = bh_kmap(sbh);
} else {
dst = kmap(page);
dst += offset;
src = bh_kmap(sbh);
}
offset = 0;
memcpy(dst, src, count);
kunmap(page);
bh_kunmap(sbh);
if (rw == READ) {
flush_dcache_page(page);
} else {
SetPageDirty(page);
}
if (unlock)
UnlockPage(page);
__free_page(page);
} while (size);
out:
return err;
}