void *
idr_find(struct idr *idr, int id)
{
void *res;
mtx_lock(&idr->lock);
res = idr_find_locked(idr, id);
mtx_unlock(&idr->lock);
return (res);
}
void *
idr_get_next(struct idr *idr, int *nextidp)
{
void *res = NULL;
int id = *nextidp;
mtx_lock(&idr->lock);
for (; id <= idr_max(idr); id++) {
res = idr_find_locked(idr, id);
if (res == NULL)
continue;
*nextidp = id;
break;
}
mtx_unlock(&idr->lock);
return (res);
}
int
idr_get_new_above(struct idr *idr, void *ptr, int starting_id, int *idp)
{
struct idr_layer *stack[MAX_LEVEL];
struct idr_layer *il;
int error;
int layer;
int idx, sidx;
int id;
error = -EAGAIN;
mtx_lock(&idr->lock);
/*
* Compute the layers required to support starting_id and the mask
* at the top layer.
*/
restart:
idx = starting_id;
layer = 0;
while (idx & ~IDR_MASK) {
layer++;
idx >>= IDR_BITS;
}
if (layer == MAX_LEVEL + 1) {
error = -ENOSPC;
goto out;
}
/*
* Expand the tree until there is free space at or beyond starting_id.
*/
while (idr->layers <= layer ||
idr->top->bitmap < (1 << idr_pos(starting_id, idr->layers - 1))) {
if (idr->layers == MAX_LEVEL + 1) {
error = -ENOSPC;
goto out;
}
il = idr_get(idr);
if (il == NULL)
goto out;
il->ary[0] = idr->top;
if (idr->top && idr->top->bitmap == 0)
il->bitmap &= ~1;
idr->top = il;
idr->layers++;
}
il = idr->top;
id = 0;
/*
* Walk the tree following free bitmaps, record our path.
*/
for (layer = idr->layers - 1;; layer--) {
stack[layer] = il;
sidx = idr_pos(starting_id, layer);
/* Returns index numbered from 0 or size if none exists. */
idx = find_next_bit(&il->bitmap, IDR_SIZE, sidx);
if (idx == IDR_SIZE && sidx == 0)
panic("idr_get_new: Invalid leaf state (%p, %p)\n",
idr, il);
/*
* We may have walked a path where there was a free bit but
* it was lower than what we wanted. Restart the search with
* a larger starting id. id contains the progress we made so
* far. Search the leaf one above this level. This may
* restart as many as MAX_LEVEL times but that is expected
* to be rare.
*/
if (idx == IDR_SIZE) {
starting_id = id + (1 << ((layer + 1) * IDR_BITS));
goto restart;
}
if (idx > sidx)
starting_id = 0; /* Search the whole subtree. */
id |= idx << (layer * IDR_BITS);
if (layer == 0)
break;
if (il->ary[idx] == NULL) {
il->ary[idx] = idr_get(idr);
if (il->ary[idx] == NULL)
goto out;
}
il = il->ary[idx];
}
/*
* Allocate the leaf to the consumer.
*/
il->bitmap &= ~(1 << idx);
il->ary[idx] = ptr;
*idp = id;
/*
* Clear bitmaps potentially up to the root.
*/
while (il->bitmap == 0 && ++layer < idr->layers) {
il = stack[layer];
il->bitmap &= ~(1 << idr_pos(id, layer));
}
error = 0;
out:
#ifdef INVARIANTS
if (error == 0 && idr_find_locked(idr, id) != ptr) {
panic("idr_get_new_above: Failed for idr %p, id %d, ptr %p\n",
idr, id, ptr);
}
#endif
mtx_unlock(&idr->lock);
return (error);
}
/*
* Could be implemented as get_new_above(idr, ptr, 0, idp) but written
* first for simplicity sake.
*/
int
idr_get_new(struct idr *idr, void *ptr, int *idp)
{
struct idr_layer *stack[MAX_LEVEL];
struct idr_layer *il;
int error;
int layer;
int idx;
int id;
error = -EAGAIN;
mtx_lock(&idr->lock);
/*
* Expand the tree until there is free space.
*/
if (idr->top == NULL || idr->top->bitmap == 0) {
if (idr->layers == MAX_LEVEL + 1) {
error = -ENOSPC;
goto out;
}
il = idr_get(idr);
if (il == NULL)
goto out;
il->ary[0] = idr->top;
if (idr->top)
il->bitmap &= ~1;
idr->top = il;
idr->layers++;
}
il = idr->top;
id = 0;
/*
* Walk the tree following free bitmaps, record our path.
*/
for (layer = idr->layers - 1;; layer--) {
stack[layer] = il;
idx = ffsl(il->bitmap);
if (idx == 0)
panic("idr_get_new: Invalid leaf state (%p, %p)\n",
idr, il);
idx--;
id |= idx << (layer * IDR_BITS);
if (layer == 0)
break;
if (il->ary[idx] == NULL) {
il->ary[idx] = idr_get(idr);
if (il->ary[idx] == NULL)
goto out;
}
il = il->ary[idx];
}
/*
* Allocate the leaf to the consumer.
*/
il->bitmap &= ~(1 << idx);
il->ary[idx] = ptr;
*idp = id;
/*
* Clear bitmaps potentially up to the root.
*/
while (il->bitmap == 0 && ++layer < idr->layers) {
il = stack[layer];
il->bitmap &= ~(1 << idr_pos(id, layer));
}
error = 0;
out:
#ifdef INVARIANTS
if (error == 0 && idr_find_locked(idr, id) != ptr) {
panic("idr_get_new: Failed for idr %p, id %d, ptr %p\n",
idr, id, ptr);
}
#endif
mtx_unlock(&idr->lock);
return (error);
}
