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Diffstat (limited to 'net/tipc/ref.c')
| -rw-r--r-- | net/tipc/ref.c | 266 |
1 files changed, 0 insertions, 266 deletions
diff --git a/net/tipc/ref.c b/net/tipc/ref.c deleted file mode 100644 index 3d4ecd754eee..000000000000 --- a/net/tipc/ref.c +++ /dev/null @@ -1,266 +0,0 @@ -/* - * net/tipc/ref.c: TIPC object registry code - * - * Copyright (c) 1991-2006, Ericsson AB - * Copyright (c) 2004-2007, Wind River Systems - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions are met: - * - * 1. Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * 2. Redistributions in binary form must reproduce the above copyright - * notice, this list of conditions and the following disclaimer in the - * documentation and/or other materials provided with the distribution. - * 3. Neither the names of the copyright holders nor the names of its - * contributors may be used to endorse or promote products derived from - * this software without specific prior written permission. - * - * Alternatively, this software may be distributed under the terms of the - * GNU General Public License ("GPL") version 2 as published by the Free - * Software Foundation. - * - * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" - * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE - * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE - * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE - * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR - * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF - * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS - * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN - * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) - * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE - * POSSIBILITY OF SUCH DAMAGE. - */ - -#include "core.h" -#include "ref.h" - -/** - * struct reference - TIPC object reference entry - * @object: pointer to object associated with reference entry - * @lock: spinlock controlling access to object - * @ref: reference value for object (combines instance & array index info) - */ -struct reference { - void *object; - spinlock_t lock; - u32 ref; -}; - -/** - * struct tipc_ref_table - table of TIPC object reference entries - * @entries: pointer to array of reference entries - * @capacity: array index of first unusable entry - * @init_point: array index of first uninitialized entry - * @first_free: array index of first unused object reference entry - * @last_free: array index of last unused object reference entry - * @index_mask: bitmask for array index portion of reference values - * @start_mask: initial value for instance value portion of reference values - */ -struct ref_table { - struct reference *entries; - u32 capacity; - u32 init_point; - u32 first_free; - u32 last_free; - u32 index_mask; - u32 start_mask; -}; - -/* - * Object reference table consists of 2**N entries. - * - * State Object ptr Reference - * ----- ---------- --------- - * In use non-NULL XXXX|own index - * (XXXX changes each time entry is acquired) - * Free NULL YYYY|next free index - * (YYYY is one more than last used XXXX) - * Uninitialized NULL 0 - * - * Entry 0 is not used; this allows index 0 to denote the end of the free list. - * - * Note that a reference value of 0 does not necessarily indicate that an - * entry is uninitialized, since the last entry in the free list could also - * have a reference value of 0 (although this is unlikely). - */ - -static struct ref_table tipc_ref_table; - -static DEFINE_SPINLOCK(ref_table_lock); - -/** - * tipc_ref_table_init - create reference table for objects - */ -int tipc_ref_table_init(u32 requested_size, u32 start) -{ - struct reference *table; - u32 actual_size; - - /* account for unused entry, then round up size to a power of 2 */ - - requested_size++; - for (actual_size = 16; actual_size < requested_size; actual_size <<= 1) - /* do nothing */ ; - - /* allocate table & mark all entries as uninitialized */ - table = vzalloc(actual_size * sizeof(struct reference)); - if (table == NULL) - return -ENOMEM; - - tipc_ref_table.entries = table; - tipc_ref_table.capacity = requested_size; - tipc_ref_table.init_point = 1; - tipc_ref_table.first_free = 0; - tipc_ref_table.last_free = 0; - tipc_ref_table.index_mask = actual_size - 1; - tipc_ref_table.start_mask = start & ~tipc_ref_table.index_mask; - - return 0; -} - -/** - * tipc_ref_table_stop - destroy reference table for objects - */ -void tipc_ref_table_stop(void) -{ - vfree(tipc_ref_table.entries); - tipc_ref_table.entries = NULL; -} - -/** - * tipc_ref_acquire - create reference to an object - * - * Register an object pointer in reference table and lock the object. - * Returns a unique reference value that is used from then on to retrieve the - * object pointer, or to determine that the object has been deregistered. - * - * Note: The object is returned in the locked state so that the caller can - * register a partially initialized object, without running the risk that - * the object will be accessed before initialization is complete. - */ -u32 tipc_ref_acquire(void *object, spinlock_t **lock) -{ - u32 index; - u32 index_mask; - u32 next_plus_upper; - u32 ref; - struct reference *entry = NULL; - - if (!object) { - pr_err("Attempt to acquire ref. to non-existent obj\n"); - return 0; - } - if (!tipc_ref_table.entries) { - pr_err("Ref. table not found in acquisition attempt\n"); - return 0; - } - - /* take a free entry, if available; otherwise initialize a new entry */ - spin_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; - next_plus_upper = entry->ref; - tipc_ref_table.first_free = next_plus_upper & index_mask; - ref = (next_plus_upper & ~index_mask) + index; - } else if (tipc_ref_table.init_point < tipc_ref_table.capacity) { - index = tipc_ref_table.init_point++; - entry = &(tipc_ref_table.entries[index]); - spin_lock_init(&entry->lock); - ref = tipc_ref_table.start_mask + index; - } else { - ref = 0; - } - spin_unlock_bh(&ref_table_lock); - - /* - * Grab the lock so no one else can modify this entry - * While we assign its ref value & object pointer - */ - if (entry) { - spin_lock_bh(&entry->lock); - entry->ref = ref; - entry->object = object; - *lock = &entry->lock; - /* - * keep it locked, the caller is responsible - * for unlocking this when they're done with it - */ - } - - return ref; -} - -/** - * 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_mask; - - if (!tipc_ref_table.entries) { - pr_err("Ref. table not found during discard attempt\n"); - return; - } - - index_mask = tipc_ref_table.index_mask; - index = ref & index_mask; - entry = &(tipc_ref_table.entries[index]); - - spin_lock_bh(&ref_table_lock); - - if (!entry->object) { - pr_err("Attempt to discard ref. to non-existent obj\n"); - goto exit; - } - if (entry->ref != ref) { - pr_err("Attempt to discard non-existent reference\n"); - goto exit; - } - - /* - * mark entry as unused; increment instance part of entry's reference - * to invalidate any subsequent references - */ - entry->object = NULL; - entry->ref = (ref & ~index_mask) + (index_mask + 1); - - /* append entry to free entry list */ - if (tipc_ref_table.first_free == 0) - tipc_ref_table.first_free = index; - else - tipc_ref_table.entries[tipc_ref_table.last_free].ref |= index; - tipc_ref_table.last_free = index; - -exit: - spin_unlock_bh(&ref_table_lock); -} - -/** - * tipc_ref_lock - lock referenced object and return pointer to it - */ -void *tipc_ref_lock(u32 ref) -{ - if (likely(tipc_ref_table.entries)) { - struct reference *entry; - - entry = &tipc_ref_table.entries[ref & - tipc_ref_table.index_mask]; - if (likely(entry->ref != 0)) { - spin_lock_bh(&entry->lock); - if (likely((entry->ref == ref) && (entry->object))) - return entry->object; - spin_unlock_bh(&entry->lock); - } - } - return NULL; -} |