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@@ -2,7 +2,7 @@
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* net/tipc/ref.c: TIPC object registry code
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* net/tipc/ref.c: TIPC object registry code
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*
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*
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* Copyright (c) 1991-2006, Ericsson AB
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* Copyright (c) 1991-2006, Ericsson AB
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- * Copyright (c) 2004-2005, Wind River Systems
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+ * Copyright (c) 2004-2007, Wind River Systems
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* All rights reserved.
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* All rights reserved.
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*
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*
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* Redistribution and use in source and binary forms, with or without
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* Redistribution and use in source and binary forms, with or without
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@@ -46,6 +46,37 @@
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#include "node.h"
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#include "node.h"
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#include "bcast.h"
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#include "bcast.h"
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+/**
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+ * struct reference - TIPC object reference entry
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+ * @object: pointer to object associated with reference entry
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+ * @lock: spinlock controlling access to object
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+ * @data: reference value associated with object (or link to next unused entry)
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+ */
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+
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+struct reference {
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+ void *object;
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+ spinlock_t lock;
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+ union {
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+ u32 next_plus_upper;
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+ u32 reference;
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+ } data;
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+};
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+
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+/**
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+ * struct tipc_ref_table - table of TIPC object reference entries
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+ * @entries: pointer to array of reference entries
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+ * @index_mask: bitmask for array index portion of reference values
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+ * @first_free: array index of first unused object reference entry
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+ * @last_free: array index of last unused object reference entry
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+ */
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+
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+struct ref_table {
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+ struct reference *entries;
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+ u32 index_mask;
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+ u32 first_free;
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+ u32 last_free;
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+};
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+
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/*
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/*
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* Object reference table consists of 2**N entries.
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* Object reference table consists of 2**N entries.
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*
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*
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@@ -61,7 +92,7 @@
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* because entry 0's reference field has the form XXXX|1--1.
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* because entry 0's reference field has the form XXXX|1--1.
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*/
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*/
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-struct ref_table tipc_ref_table = { NULL };
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+static struct ref_table tipc_ref_table = { NULL };
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static DEFINE_RWLOCK(ref_table_lock);
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static DEFINE_RWLOCK(ref_table_lock);
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@@ -198,8 +229,8 @@ void tipc_ref_discard(u32 ref)
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tipc_ref_table.first_free = index;
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tipc_ref_table.first_free = index;
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else
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else
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/* next_plus_upper is always XXXX|0--0 for last free entry */
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/* next_plus_upper is always XXXX|0--0 for last free entry */
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- tipc_ref_table.entries[tipc_ref_table.last_free].data.next_plus_upper
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- |= index;
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+ tipc_ref_table.entries[tipc_ref_table.last_free].
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+ data.next_plus_upper |= index;
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tipc_ref_table.last_free = index;
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tipc_ref_table.last_free = index;
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/* increment upper bits of entry to invalidate subsequent references */
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/* increment upper bits of entry to invalidate subsequent references */
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@@ -208,3 +239,55 @@ exit:
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write_unlock_bh(&ref_table_lock);
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write_unlock_bh(&ref_table_lock);
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}
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}
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+/**
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+ * tipc_ref_lock - lock referenced object and return pointer to it
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+ */
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+
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+void *tipc_ref_lock(u32 ref)
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+{
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+ if (likely(tipc_ref_table.entries)) {
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+ struct reference *r;
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+
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+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
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+ spin_lock_bh(&r->lock);
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+ if (likely(r->data.reference == ref))
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+ return r->object;
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+ spin_unlock_bh(&r->lock);
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+ }
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+ return NULL;
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+}
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+
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+/**
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+ * tipc_ref_unlock - unlock referenced object
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+ */
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+
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+void tipc_ref_unlock(u32 ref)
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+{
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+ if (likely(tipc_ref_table.entries)) {
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+ struct reference *r;
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+
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+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
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+ if (likely(r->data.reference == ref))
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+ spin_unlock_bh(&r->lock);
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+ else
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+ err("tipc_ref_unlock() invoked using "
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+ "obsolete reference\n");
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+ }
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+}
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+
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+/**
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+ * tipc_ref_deref - return pointer referenced object (without locking it)
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+ */
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+
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+void *tipc_ref_deref(u32 ref)
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+{
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+ if (likely(tipc_ref_table.entries)) {
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+ struct reference *r;
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+
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+ r = &tipc_ref_table.entries[ref & tipc_ref_table.index_mask];
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+ if (likely(r->data.reference == ref))
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+ return r->object;
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+ }
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+ return NULL;
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+}
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+
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