Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / infiniband / hw / cxgb4 / id_table.c

diff --git a/kernel/drivers/infiniband/hw/cxgb4/id_table.c b/kernel/drivers/infiniband/hw/cxgb4/id_table.c
new file mode 100644 (file)
index 0000000..0161ae6
--- /dev/null
+++ b/kernel/drivers/infiniband/hw/cxgb4/id_table.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2011 Chelsio Communications.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - 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.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <linux/kernel.h>
+#include <linux/random.h>
+#include "iw_cxgb4.h"
+
+#define RANDOM_SKIP 16
+
+/*
+ * Trivial bitmap-based allocator. If the random flag is set, the
+ * allocator is designed to:
+ * - pseudo-randomize the id returned such that it is not trivially predictable.
+ * - avoid reuse of recently used id (at the expense of predictability)
+ */
+u32 c4iw_id_alloc(struct c4iw_id_table *alloc)
+{
+       unsigned long flags;
+       u32 obj;
+
+       spin_lock_irqsave(&alloc->lock, flags);
+
+       obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last);
+       if (obj >= alloc->max)
+               obj = find_first_zero_bit(alloc->table, alloc->max);
+
+       if (obj < alloc->max) {
+               if (alloc->flags & C4IW_ID_TABLE_F_RANDOM)
+                       alloc->last += prandom_u32() % RANDOM_SKIP;
+               else
+                       alloc->last = obj + 1;
+               if (alloc->last >= alloc->max)
+                       alloc->last = 0;
+               set_bit(obj, alloc->table);
+               obj += alloc->start;
+       } else
+               obj = -1;
+
+       spin_unlock_irqrestore(&alloc->lock, flags);
+       return obj;
+}
+
+void c4iw_id_free(struct c4iw_id_table *alloc, u32 obj)
+{
+       unsigned long flags;
+
+       obj -= alloc->start;
+       BUG_ON((int)obj < 0);
+
+       spin_lock_irqsave(&alloc->lock, flags);
+       clear_bit(obj, alloc->table);
+       spin_unlock_irqrestore(&alloc->lock, flags);
+}
+
+int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num,
+                       u32 reserved, u32 flags)
+{
+       int i;
+
+       alloc->start = start;
+       alloc->flags = flags;
+       if (flags & C4IW_ID_TABLE_F_RANDOM)
+               alloc->last = prandom_u32() % RANDOM_SKIP;
+       else
+               alloc->last = 0;
+       alloc->max  = num;
+       spin_lock_init(&alloc->lock);
+       alloc->table = kmalloc(BITS_TO_LONGS(num) * sizeof(long),
+                               GFP_KERNEL);
+       if (!alloc->table)
+               return -ENOMEM;
+
+       bitmap_zero(alloc->table, num);
+       if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY))
+               for (i = 0; i < reserved; ++i)
+                       set_bit(i, alloc->table);
+
+       return 0;
+}
+
+void c4iw_id_table_free(struct c4iw_id_table *alloc)
+{
+       kfree(alloc->table);
+}