/*
* net/tipc/ref.c: TIPC object registry code
- *
+ *
* Copyright (c) 1991-2006, Ericsson AB
* Copyright (c) 2004-2005, Wind River Systems
* All rights reserved.
* Object reference table consists of 2**N entries.
*
* A used entry has object ptr != 0, reference == XXXX|own index
- * (XXXX changes each time entry is acquired)
+ * (XXXX changes each time entry is acquired)
* A free entry has object ptr == 0, reference == YYYY|next free index
* (YYYY is one more than last used XXXX)
*
- * Free list is initially chained from entry (2**N)-1 to entry 1.
+ * Free list is initially chained from entry (2**N)-1 to entry 1.
* Entry 0 is not used to allow index 0 to indicate the end of the free list.
*
* Note: Any accidental reference of the form XXXX|0--0 won't match entry 0
struct ref_table tipc_ref_table = { NULL };
-static rwlock_t ref_table_lock = RW_LOCK_UNLOCKED;
+static DEFINE_RWLOCK(ref_table_lock);
/**
* tipc_ref_table_init - create reference table for objects
while (sz < requested_size) {
sz <<= 1;
}
- table = (struct reference *)vmalloc(sz * sizeof(struct reference));
+ table = vmalloc(sz * sizeof(*table));
if (table == NULL)
return -ENOMEM;
index_mask = sz - 1;
for (i = sz - 1; i >= 0; i--) {
table[i].object = NULL;
- table[i].lock = SPIN_LOCK_UNLOCKED;
+ spin_lock_init(&table[i].lock);
table[i].data.next_plus_upper = (start & ~index_mask) + i - 1;
}
tipc_ref_table.entries = table;
/**
* tipc_ref_acquire - create reference to an object
- *
+ *
* Return a unique reference value which can be translated back to the pointer
- * 'object' at a later time. Also, pass back a pointer to the lock protecting
+ * 'object' at a later time. Also, pass back a pointer to the lock protecting
* the object, but without locking it.
*/
u32 next_plus_upper;
u32 reference = 0;
- assert(tipc_ref_table.entries && object);
+ if (!object) {
+ err("Attempt to acquire reference to non-existent object\n");
+ return 0;
+ }
+ if (!tipc_ref_table.entries) {
+ err("Reference table not found during acquisition attempt\n");
+ return 0;
+ }
write_lock_bh(&ref_table_lock);
if (tipc_ref_table.first_free) {
index = tipc_ref_table.first_free;
entry = &(tipc_ref_table.entries[index]);
index_mask = tipc_ref_table.index_mask;
- /* take lock in case a previous user of entry still holds it */
- spin_lock_bh(&entry->lock);
+ /* take lock in case a previous user of entry still holds it */
+ spin_lock_bh(&entry->lock);
next_plus_upper = entry->data.next_plus_upper;
tipc_ref_table.first_free = next_plus_upper & index_mask;
reference = (next_plus_upper & ~index_mask) + index;
entry->data.reference = reference;
entry->object = object;
- if (lock != 0)
- *lock = &entry->lock;
+ if (lock != 0)
+ *lock = &entry->lock;
spin_unlock_bh(&entry->lock);
}
write_unlock_bh(&ref_table_lock);
/**
* tipc_ref_discard - invalidate references to an object
- *
+ *
* Disallow future references to an object and free up the entry for re-use.
* Note: The entry's spin_lock may still be busy after discard
*/
void tipc_ref_discard(u32 ref)
{
struct reference *entry;
- u32 index;
+ u32 index;
u32 index_mask;
- assert(tipc_ref_table.entries);
- assert(ref != 0);
+ if (!ref) {
+ err("Attempt to discard reference 0\n");
+ return;
+ }
+ if (!tipc_ref_table.entries) {
+ err("Reference table not found during discard attempt\n");
+ return;
+ }
write_lock_bh(&ref_table_lock);
index_mask = tipc_ref_table.index_mask;
index = ref & index_mask;
entry = &(tipc_ref_table.entries[index]);
- assert(entry->object != 0);
- assert(entry->data.reference == ref);
+
+ if (!entry->object) {
+ err("Attempt to discard reference to non-existent object\n");
+ goto exit;
+ }
+ if (entry->data.reference != ref) {
+ err("Attempt to discard non-existent reference\n");
+ goto exit;
+ }
/* mark entry as unused */
entry->object = NULL;
tipc_ref_table.first_free = index;
else
/* next_plus_upper is always XXXX|0--0 for last free entry */
- tipc_ref_table.entries[tipc_ref_table.last_free].data.next_plus_upper
+ tipc_ref_table.entries[tipc_ref_table.last_free].data.next_plus_upper
|= index;
tipc_ref_table.last_free = index;
/* increment upper bits of entry to invalidate subsequent references */
entry->data.next_plus_upper = (ref & ~index_mask) + (index_mask + 1);
+exit:
write_unlock_bh(&ref_table_lock);
}