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o Added two new functions get_child [Andrew Clausen] and get_node. I think

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this makes 'high()' a bit more understandable.
This commit is contained in:
Joe Thornber 2001-09-04 10:17:28 +00:00
parent a612e52245
commit e69ce84e34
3 changed files with 34 additions and 15 deletions
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18
driver/device-mapper/dm-table.c
View File

@ -64,10 +64,10 @@ static offset_t high(struct dm_table *t, int l, int n)
return (offset_t) -1;
if (l == t->depth - 1)
return t->index[l][((n + 1) * KEYS_PER_NODE) - 1];
return get_node(t, l, n)[KEYS_PER_NODE - 1];
l++;
n = (n + 1) * CHILD_PER_NODE - 1;
n = get_child(n, CHILDREN_PER_NODE - 1);
}
return -1;
@ -82,12 +82,14 @@ static int setup_btree_index(int l, struct dm_table *t)
int n, c, cn;
for (n = 0, cn = 0; n < t->counts[l]; n++) {
offset_t *k = t->index[l] + (n * KEYS_PER_NODE);
offset_t *node = get_node(t, l, n);
for (c = 0; c < KEYS_PER_NODE; c++)
k[c] = high(t, l + 1, cn++);
cn++; /* one extra for the child that's
greater than all keys */
node[c] = high(t, l + 1, cn++);
/* one extra for the child that's greater
than all keys in the node */
cn++;
}
return 0;
@ -313,7 +315,7 @@ int dm_table_complete(struct dm_table *t)
/* how many indexes will the btree have ? */
leaf_nodes = div_up(t->num_targets, KEYS_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILD_PER_NODE);
t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
/* leaf layer has already been set up */
t->counts[t->depth - 1] = leaf_nodes;
@ -321,7 +323,7 @@ int dm_table_complete(struct dm_table *t)
/* set up internal nodes, bottom-up */
for (i = t->depth - 2; i >= 0; i--) {
t->counts[i] = div_up(t->counts[i + 1], CHILD_PER_NODE);
t->counts[i] = div_up(t->counts[i + 1], CHILDREN_PER_NODE);
t->index[i] = vmalloc(NODE_SIZE * t->counts[i]);
setup_btree_index(i, t);
}

12
driver/device-mapper/dm.c
View File

@ -338,19 +338,19 @@ static inline int __map_buffer(struct mapped_device *md,
*/
static inline int __find_node(struct dm_table *t, struct buffer_head *bh)
{
int i = 0, l, r = 0;
int l, n = 0, k = 0;
offset_t *node;
for (l = 0; l < t->depth; l++) {
r = (CHILD_PER_NODE * r) + i;
node = t->index[l] + (r * KEYS_PER_NODE);
n = get_child(n, k);
node = get_node(t, l, n);
for (i = 0; i < KEYS_PER_NODE; i++)
if (node[i] >= bh->b_rsector)
for (k = 0; k < KEYS_PER_NODE; k++)
if (node[k] >= bh->b_rsector)
break;
}
return (KEYS_PER_NODE * r) + i;
return (KEYS_PER_NODE * n) + k;
}
static int request(request_queue_t *q, int rw, struct buffer_head *bh)

19
driver/device-mapper/dm.h
View File

@ -134,7 +134,7 @@
#define MAX_DEPTH 16
#define NODE_SIZE L1_CACHE_BYTES
#define KEYS_PER_NODE (NODE_SIZE / sizeof(offset_t))
#define CHILD_PER_NODE (KEYS_PER_NODE + 1)
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
#define DM_NAME_LEN 64
enum {
@ -263,6 +263,23 @@ int dm_fs_remove(struct mapped_device *md);
#define WARN(f, x...) printk(KERN_WARNING "device-mapper: " f "\n" , ## x)
/*
* calculate the index of the child node of the
* n'th node k'th key.
*/
static inline int get_child(int n, int k)
{
return (n * CHILDREN_PER_NODE) + k;
}
/*
* returns the n'th node of level l from table t.
*/
static inline offset_t *get_node(struct dm_table *t, int l, int n)
{
return t->index[l] + (n * KEYS_PER_NODE);
}
static inline int is_active(struct mapped_device *md)
{
return test_bit(DM_ACTIVE, &md->state);