linux/drivers/scsi/isci/pool.h

/*
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
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 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
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 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 * The full GNU General Public License is included in this distribution
 * in the file called LICENSE.GPL.
 *
 * BSD LICENSE
 *
 * Copyright(c) 2008 - 2011 Intel Corporation. All rights reserved.
 * All rights reserved.
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 * modification, are permitted provided that the following conditions
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 *     notice, this list of conditions and the following disclaimer.
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 *     from this software without specific prior written permission.
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/**
 * This file contains the interface to the pool class. This class allows two
 *    different two different priority tasks to insert and remove items from
 *    the free pool. The user of the pool is expected to evaluate the pool
 *    condition empty before a get operation and pool condition full before a
 *    put operation. Methods Provided: - sci_pool_create() -
 *    sci_pool_initialize() - sci_pool_empty() - sci_pool_full() -
 *    sci_pool_get() - sci_pool_put()
 *
 *
 */

#ifndef _SCI_POOL_H_
#define _SCI_POOL_H_

/**
 * SCI_POOL_INCREMENT() -
 *
 * Private operation for the pool
 */
#define SCI_POOL_INCREMENT(pool, index) \
	(((index) + 1) == (pool).size ? 0 : (index) + 1)

/**
 * SCI_POOL_CREATE() -
 *
 * This creates a pool structure of pool_name. The members in the pool are of
 * type with number of elements equal to size.
 */
#define SCI_POOL_CREATE(pool_name, type, pool_size) \
	struct \
	{ \
		u32 size; \
		u32 get; \
		u32 put; \
		type array[(pool_size) + 1]; \
	} pool_name


/**
 * sci_pool_empty() -
 *
 * This macro evaluates the pool and returns true if the pool is empty. If the
 * pool is empty the user should not perform any get operation on the pool.
 */
#define sci_pool_empty(pool) \
	((pool).get == (pool).put)

/**
 * sci_pool_full() -
 *
 * This macro evaluates the pool and returns true if the pool is full.  If the
 * pool is full the user should not perform any put operation.
 */
#define sci_pool_full(pool) \
	(SCI_POOL_INCREMENT(pool, (pool).put) == (pool).get)

/**
 * sci_pool_size() -
 *
 * This macro returns the size of the pool created.  The internal size of the
 * pool is actually 1 larger then necessary in order to ensure get and put
 * pointers can be written simultaneously by different users.  As a result,
 * this macro subtracts 1 from the internal size
 */
#define sci_pool_size(pool) \
	((pool).size - 1)

/**
 * sci_pool_count() -
 *
 * This macro indicates the number of elements currently contained in the pool.
 */
#define sci_pool_count(pool) \
	(\
		sci_pool_empty((pool)) \
		? 0 \
		: (\
			sci_pool_full((pool)) \
			? sci_pool_size((pool)) \
			: (\
				(pool).get > (pool).put \
				? ((pool).size - (pool).get + (pool).put) \
				: ((pool).put - (pool).get) \
				) \
			) \
	)

/**
 * sci_pool_initialize() -
 *
 * This macro initializes the pool to an empty condition.
 */
#define sci_pool_initialize(pool) \
	{ \
		(pool).size = (sizeof((pool).array) / sizeof((pool).array[0])); \
		(pool).get = 0; \
		(pool).put = 0; \
	}

/**
 * sci_pool_get() -
 *
 * This macro will get the next free element from the pool. This should only be
 * called if the pool is not empty.
 */
#define sci_pool_get(pool, my_value) \
	{ \
		(my_value) = (pool).array[(pool).get]; \
		(pool).get = SCI_POOL_INCREMENT((pool), (pool).get); \
	}

/**
 * sci_pool_put() -
 *
 * This macro will put the value into the pool. This should only be called if
 * the pool is not full.
 */
#define sci_pool_put(pool, value) \
	{ \
		(pool).array[(pool).put] = (value); \
		(pool).put = SCI_POOL_INCREMENT((pool), (pool).put); \
	}

/**
 * sci_pool_erase() -
 *
 * This macro will search the pool and remove any elements in the pool matching
 * the supplied value. This method can only be utilized on pools
 */
#define sci_pool_erase(pool, type, value) \
	{ \
		type tmp_value;	\
		u32 index; \
		u32 element_count = sci_pool_count((pool)); \
 \
		for (index = 0; index < element_count; index++) {	\
			sci_pool_get((pool), tmp_value); \
			if (tmp_value != (value)) \
				sci_pool_put((pool), tmp_value); \
		} \
	}

#endif /* _SCI_POOL_H_ */