/*
* This initializes the initial buffer free list. nr_buffers is set
* to one less the actual number of buffers, as a sop to backwards
* compatibility --- the old code did this (I think unintentionally,
* but I'm not sure), and programs in the ps package expect it.
* - TYT 8/30/92
*/
void buffer_init(void)
{
int i;
for (i = 0 ; i < NR_HASH ; i++)
hash_table[i] = NULL;
free_list = 0;
grow_buffers(BLOCK_SIZE);
if (!free_list)
panic("Unable to initialize buffer free list!");
return;
}
/*
* This initializes the initial buffer free list. nr_buffers is set
* to one less the actual number of buffers, as a sop to backwards
* compatibility --- the old code did this (I think unintentionally,
* but I'm not sure), and programs in the ps package expect it.
* - TYT 8/30/92
*/
void buffer_init(void)
{
int i;
if (high_memory >= 4*1024*1024)
min_free_pages = 200;
else
min_free_pages = 20;
for (i = 0 ; i < NR_HASH ; i++)
hash_table[i] = NULL;
free_list = 0;
grow_buffers(GFP_KERNEL, BLOCK_SIZE);
if (!free_list)
panic("VFS: Unable to initialize buffer free list!");
return;
}
struct buffer_head * getblk(int dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
repeat:
if (bh = get_hash_table(dev, block, size))
return bh;
if (nr_free_pages > 30)
grow_buffers(size);
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt)
ll_rw_block(WRITEA,tmp);
#endif
}
if (!bh && nr_free_pages > 5) {
grow_buffers(size);
goto repeat;
}
/* and repeat until we find something good */
if (!bh) {
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(bh->b_dev);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of it's kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
struct buffer_head * getblk(dev_t dev, int block, int size)
{
struct buffer_head * bh, * tmp;
int buffers;
static int grow_size = 0;
repeat:
bh = get_hash_table(dev, block, size);
if (bh) {
if (bh->b_uptodate && !bh->b_dirt)
put_last_free(bh);
return bh;
}
grow_size -= size;
if (nr_free_pages > min_free_pages && grow_size <= 0) {
if (grow_buffers(GFP_BUFFER, size))
grow_size = PAGE_SIZE;
}
buffers = nr_buffers;
bh = NULL;
for (tmp = free_list; buffers-- > 0 ; tmp = tmp->b_next_free) {
if (tmp->b_count || tmp->b_size != size)
continue;
if (mem_map[MAP_NR((unsigned long) tmp->b_data)] != 1)
continue;
if (!bh || BADNESS(tmp)<BADNESS(bh)) {
bh = tmp;
if (!BADNESS(tmp))
break;
}
#if 0
if (tmp->b_dirt) {
tmp->b_count++;
ll_rw_block(WRITEA, 1, &tmp);
tmp->b_count--;
}
#endif
}
if (!bh) {
if (nr_free_pages > 5)
if (grow_buffers(GFP_BUFFER, size))
goto repeat;
if (!grow_buffers(GFP_ATOMIC, size))
sleep_on(&buffer_wait);
goto repeat;
}
wait_on_buffer(bh);
if (bh->b_count || bh->b_size != size)
goto repeat;
if (bh->b_dirt) {
sync_buffers(0,0);
goto repeat;
}
/* NOTE!! While we slept waiting for this block, somebody else might */
/* already have added "this" block to the cache. check it */
if (find_buffer(dev,block,size))
goto repeat;
/* OK, FINALLY we know that this buffer is the only one of its kind, */
/* and that it's unused (b_count=0), unlocked (b_lock=0), and clean */
bh->b_count=1;
bh->b_dirt=0;
bh->b_uptodate=0;
bh->b_req=0;
remove_from_queues(bh);
bh->b_dev=dev;
bh->b_blocknr=block;
insert_into_queues(bh);
return bh;
}
