@@ -91,6 +91,69 @@ struct block_op {
dm_block_t block;
};
+struct bop_ring_buffer {
+ unsigned begin;
+ unsigned end;
+ struct block_op bops[MAX_RECURSIVE_ALLOCATIONS + 1];
+};
+
+static void brb_init(struct bop_ring_buffer *brb)
+{
+ brb->begin = 0;
+ brb->end = 0;
+}
+
+static bool brb_empty(struct bop_ring_buffer *brb)
+{
+ return brb->begin == brb->end;
+}
+
+static unsigned brb_next(struct bop_ring_buffer *brb, unsigned old)
+{
+ unsigned r = old + 1;
+ return (r >= (sizeof(brb->bops) / sizeof(*brb->bops))) ? 0 : r;
+}
+
+static int brb_push(struct bop_ring_buffer *brb,
+ enum block_op_type type, dm_block_t b)
+{
+ struct block_op *bop;
+ unsigned next = brb_next(brb, brb->end);
+
+ /*
+ * We don't allow the last bop to be filled, this way we can
+ * differentiate between full and empty.
+ */
+ if (next == brb->begin)
+ return -ENOMEM;
+
+ bop = brb->bops + brb->end;
+ bop->type = type;
+ bop->block = b;
+
+ brb->end = next;
+
+ return 0;
+}
+
+static int brb_pop(struct bop_ring_buffer *brb, struct block_op *result)
+{
+ struct block_op *bop;
+
+ if (brb_empty(brb))
+ return -ENODATA;
+
+ bop = brb->bops + brb->begin;
+ result->type = bop->type;
+ result->block = bop->block;
+
+ brb->begin = brb_next(brb, brb->begin);
+
+ return 0;
+}
+
+/*----------------------------------------------------------------*/
+
struct sm_metadata {
struct dm_space_map sm;
@@ -101,25 +164,20 @@ struct sm_metadata {
unsigned recursion_count;
unsigned allocated_this_transaction;
- unsigned nr_uncommitted;
- struct block_op uncommitted[MAX_RECURSIVE_ALLOCATIONS];
+ struct bop_ring_buffer uncommitted;
struct threshold threshold;
};
static int add_bop(struct sm_metadata *smm, enum block_op_type type, dm_block_t b)
{
- struct block_op *op;
+ int r = brb_push(&smm->uncommitted, type, b);
- if (smm->nr_uncommitted == MAX_RECURSIVE_ALLOCATIONS) {
+ if (r) {
DMERR("too many recursive allocations");
return -ENOMEM;
}
- op = smm->uncommitted + smm->nr_uncommitted++;
- op->type = type;
- op->block = b;
-
return 0;
}
@@ -158,11 +216,17 @@ static int out(struct sm_metadata *smm)
return -ENOMEM;
}
- if (smm->recursion_count == 1 && smm->nr_uncommitted) {
- while (smm->nr_uncommitted && !r) {
- smm->nr_uncommitted--;
- r = commit_bop(smm, smm->uncommitted +
- smm->nr_uncommitted);
+ if (smm->recursion_count == 1) {
+ while (!brb_empty(&smm->uncommitted)) {
+ struct block_op bop;
+
+ r = brb_pop(&smm->uncommitted, &bop);
+ if (r) {
+ DMERR("bug in bop ring buffer");
+ break;
+ }
+
+ r = commit_bop(smm, &bop);
if (r)
break;
}
@@ -217,7 +281,8 @@ static int sm_metadata_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
uint32_t *result)
{
- int r, i;
+ int r;
+ unsigned i;
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
unsigned adjustment = 0;
@@ -225,8 +290,10 @@ static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
* We may have some uncommitted adjustments to add. This list
* should always be really short.
*/
- for (i = 0; i < smm->nr_uncommitted; i++) {
- struct block_op *op = smm->uncommitted + i;
+ for (i = smm->uncommitted.begin;
+ i != smm->uncommitted.end;
+ i = brb_next(&smm->uncommitted, i)) {
+ struct block_op *op = smm->uncommitted.bops + i;
if (op->block != b)
continue;
@@ -254,7 +321,8 @@ static int sm_metadata_get_count(struct dm_space_map *sm, dm_block_t b,
static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
dm_block_t b, int *result)
{
- int r, i, adjustment = 0;
+ int r, adjustment = 0;
+ unsigned i;
struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
uint32_t rc;
@@ -262,8 +330,11 @@ static int sm_metadata_count_is_more_than_one(struct dm_space_map *sm,
* We may have some uncommitted adjustments to add. This list
* should always be really short.
*/
- for (i = 0; i < smm->nr_uncommitted; i++) {
- struct block_op *op = smm->uncommitted + i;
+ for (i = smm->uncommitted.begin;
+ i != smm->uncommitted.end;
+ i = brb_next(&smm->uncommitted, i)) {
+
+ struct block_op *op = smm->uncommitted.bops + i;
if (op->block != b)
continue;
@@ -671,7 +742,7 @@ int dm_sm_metadata_create(struct dm_space_map *sm,
smm->begin = superblock + 1;
smm->recursion_count = 0;
smm->allocated_this_transaction = 0;
- smm->nr_uncommitted = 0;
+ brb_init(&smm->uncommitted);
threshold_init(&smm->threshold);
memcpy(&smm->sm, &bootstrap_ops, sizeof(smm->sm));
@@ -713,7 +784,7 @@ int dm_sm_metadata_open(struct dm_space_map *sm,
smm->begin = 0;
smm->recursion_count = 0;
smm->allocated_this_transaction = 0;
- smm->nr_uncommitted = 0;
+ brb_init(&smm->uncommitted);
threshold_init(&smm->threshold);
memcpy(&smm->old_ll, &smm->ll, sizeof(smm->old_ll));