static void nfs4_callback_free_slot(struct nfs4_session *session)
{
struct nfs4_slot_table *tbl = &session->bc_slot_table;
spin_lock(&tbl->slot_tbl_lock);
/*
* Let the state manager know callback processing done.
* A single slot, so highest used slotid is either 0 or -1
*/
tbl->highest_used_slotid = NFS4_NO_SLOT;
nfs4_slot_tbl_drain_complete(tbl);
spin_unlock(&tbl->slot_tbl_lock);
}
/*
* nfs4_free_slot - free a slot and efficiently update slot table.
*
* freeing a slot is trivially done by clearing its respective bit
* in the bitmap.
* If the freed slotid equals highest_used_slotid we want to update it
* so that the server would be able to size down the slot table if needed,
* otherwise we know that the highest_used_slotid is still in use.
* When updating highest_used_slotid there may be "holes" in the bitmap
* so we need to scan down from highest_used_slotid to 0 looking for the now
* highest slotid in use.
* If none found, highest_used_slotid is set to NFS4_NO_SLOT.
*
* Must be called while holding tbl->slot_tbl_lock
*/
void nfs4_free_slot(struct nfs4_slot_table *tbl, struct nfs4_slot *slot)
{
u32 slotid = slot->slot_nr;
/* clear used bit in bitmap */
__clear_bit(slotid, tbl->used_slots);
/* update highest_used_slotid when it is freed */
if (slotid == tbl->highest_used_slotid) {
u32 new_max = find_last_bit(tbl->used_slots, slotid);
if (new_max < slotid)
tbl->highest_used_slotid = new_max;
else {
tbl->highest_used_slotid = NFS4_NO_SLOT;
nfs4_slot_tbl_drain_complete(tbl);
}
}
dprintk("%s: slotid %u highest_used_slotid %u\n", __func__,
slotid, tbl->highest_used_slotid);
}
