diff options
Diffstat (limited to 'net/tipc/ref.c')
-rw-r--r-- | net/tipc/ref.c | 270 |
1 files changed, 0 insertions, 270 deletions
diff --git a/net/tipc/ref.c b/net/tipc/ref.c deleted file mode 100644 index ea981bed967b..000000000000 --- a/net/tipc/ref.c +++ /dev/null @@ -1,270 +0,0 @@ -/* - * net/tipc/ref.c: TIPC socket registry code - * - * Copyright (c) 1991-2006, 2014, 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 socket reference entry - * @tsk: pointer to socket associated with reference entry - * @ref: reference value for socket (combines instance & array index info) - */ -struct reference { - struct tipc_sock *tsk; - u32 ref; -}; - -/** - * struct tipc_ref_table - table of TIPC socket 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 socket reference entry - * @last_free: array index of last unused socket 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; -}; - -/* - * Socket reference table consists of 2**N entries. - * - * State Socket 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_RWLOCK(ref_table_lock); - -/** - * tipc_ref_table_init - create reference table for sockets - */ -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 sockets - */ -void tipc_ref_table_stop(void) -{ - if (!tipc_ref_table.entries) - return; - vfree(tipc_ref_table.entries); - tipc_ref_table.entries = NULL; -} - -/* tipc_ref_acquire - create reference to a socket - * - * Register an socket pointer in the reference table. - * Returns a unique reference value that is used from then on to retrieve the - * socket pointer, or to determine if the socket has been deregistered. - */ -u32 tipc_ref_acquire(struct tipc_sock *tsk) -{ - u32 index; - u32 index_mask; - u32 next_plus_upper; - u32 ref = 0; - struct reference *entry; - - if (unlikely(!tsk)) { - pr_err("Attempt to acquire ref. to non-existent obj\n"); - return 0; - } - if (unlikely(!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 one */ - write_lock_bh(&ref_table_lock); - index = tipc_ref_table.first_free; - entry = &tipc_ref_table.entries[index]; - - if (likely(index)) { - 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; - entry->tsk = tsk; - } else if (tipc_ref_table.init_point < tipc_ref_table.capacity) { - index = tipc_ref_table.init_point++; - entry = &(tipc_ref_table.entries[index]); - ref = tipc_ref_table.start_mask + index; - } - - if (ref) { - entry->ref = ref; - entry->tsk = tsk; - } - write_unlock_bh(&ref_table_lock); - return ref; -} - -/* tipc_ref_discard - invalidate reference to an socket - * - * Disallow future references to an socket and free up the entry for re-use. - */ -void tipc_ref_discard(u32 ref) -{ - struct reference *entry; - u32 index; - u32 index_mask; - - if (unlikely(!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]); - - write_lock_bh(&ref_table_lock); - - if (unlikely(!entry->tsk)) { - pr_err("Attempt to discard ref. to non-existent socket\n"); - goto exit; - } - if (unlikely(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->tsk = NULL; - entry->ref = (ref & ~index_mask) + (index_mask + 1); - - /* Append entry to free entry list */ - if (unlikely(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: - write_unlock_bh(&ref_table_lock); -} - -/* tipc_sk_get - find referenced socket and return pointer to it - */ -struct tipc_sock *tipc_sk_get(u32 ref) -{ - struct reference *entry; - struct tipc_sock *tsk; - - if (unlikely(!tipc_ref_table.entries)) - return NULL; - read_lock_bh(&ref_table_lock); - entry = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask]; - tsk = entry->tsk; - if (likely(tsk && (entry->ref == ref))) - sock_hold(&tsk->sk); - else - tsk = NULL; - read_unlock_bh(&ref_table_lock); - return tsk; -} - -/* tipc_sk_get_next - lock & return next socket after referenced one -*/ -struct tipc_sock *tipc_sk_get_next(u32 *ref) -{ - struct reference *entry; - struct tipc_sock *tsk = NULL; - uint index = *ref & tipc_ref_table.index_mask; - - read_lock_bh(&ref_table_lock); - while (++index < tipc_ref_table.capacity) { - entry = &tipc_ref_table.entries[index]; - if (!entry->tsk) - continue; - tsk = entry->tsk; - sock_hold(&tsk->sk); - *ref = entry->ref; - break; - } - read_unlock_bh(&ref_table_lock); - return tsk; -} |