include/acpi/acexcep.h


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299

/******************************************************************************
 *
 * Name: acexcep.h - Exception codes returned by the ACPI subsystem
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2006, R. Byron Moore
 * 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,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any 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.
 *
 * NO WARRANTY
 * 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 MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
 */

#ifndef __ACEXCEP_H__
#define __ACEXCEP_H__

/*
 * Exceptions returned by external ACPI interfaces
 */
#define AE_CODE_ENVIRONMENTAL           0x0000
#define AE_CODE_PROGRAMMER              0x1000
#define AE_CODE_ACPI_TABLES             0x2000
#define AE_CODE_AML                     0x3000
#define AE_CODE_CONTROL                 0x4000
#define AE_CODE_MASK                    0xF000

#define ACPI_SUCCESS(a)                 (!(a))
#define ACPI_FAILURE(a)                 (a)

#define AE_OK                           (acpi_status) 0x0000

/*
 * Environmental exceptions
 */
#define AE_ERROR                        (acpi_status) (0x0001 | AE_CODE_ENVIRONMENTAL)
#define AE_NO_ACPI_TABLES               (acpi_status) (0x0002 | AE_CODE_ENVIRONMENTAL)
#define AE_NO_NAMESPACE                 (acpi_status) (0x0003 | AE_CODE_ENVIRONMENTAL)
#define AE_NO_MEMORY                    (acpi_status) (0x0004 | AE_CODE_ENVIRONMENTAL)
#define AE_NOT_FOUND                    (acpi_status) (0x0005 | AE_CODE_ENVIRONMENTAL)
#define AE_NOT_EXIST                    (acpi_status) (0x0006 | AE_CODE_ENVIRONMENTAL)
#define AE_ALREADY_EXISTS               (acpi_status) (0x0007 | AE_CODE_ENVIRONMENTAL)
#define AE_TYPE                         (acpi_status) (0x0008 | AE_CODE_ENVIRONMENTAL)
#define AE_NULL_OBJECT                  (acpi_status) (0x0009 | AE_CODE_ENVIRONMENTAL)
#define AE_NULL_ENTRY                   (acpi_status) (0x000A | AE_CODE_ENVIRONMENTAL)
#define AE_BUFFER_OVERFLOW              (acpi_status) (0x000B | AE_CODE_ENVIRONMENTAL)
#define AE_STACK_OVERFLOW               (acpi_status) (0x000C | AE_CODE_ENVIRONMENTAL)
#define AE_STACK_UNDERFLOW              (acpi_status) (0x000D | AE_CODE_ENVIRONMENTAL)
#define AE_NOT_IMPLEMENTED              (acpi_status) (0x000E | AE_CODE_ENVIRONMENTAL)
#define AE_VERSION_MISMATCH             (acpi_status) (0x000F | AE_CODE_ENVIRONMENTAL)
#define AE_SUPPORT                      (acpi_status) (0x0010 | AE_CODE_ENVIRONMENTAL)
#define AE_SHARE                        (acpi_status) (0x0011 | AE_CODE_ENVIRONMENTAL)
#define AE_LIMIT                        (acpi_status) (0x0012 | AE_CODE_ENVIRONMENTAL)
#define AE_TIME                         (acpi_status) (0x0013 | AE_CODE_ENVIRONMENTAL)
#define AE_UNKNOWN_STATUS               (acpi_status) (0x0014 | AE_CODE_ENVIRONMENTAL)
#define AE_ACQUIRE_DEADLOCK             (acpi_status) (0x0015 | AE_CODE_ENVIRONMENTAL)
#define AE_RELEASE_DEADLOCK             (acpi_status) (0x0016 | AE_CODE_ENVIRONMENTAL)
#define AE_NOT_ACQUIRED                 (acpi_status) (0x0017 | AE_CODE_ENVIRONMENTAL)
#define AE_ALREADY_ACQUIRED             (acpi_status) (0x0018 | AE_CODE_ENVIRONMENTAL)
#define AE_NO_HARDWARE_RESPONSE         (acpi_status) (0x0019 | AE_CODE_ENVIRONMENTAL)
#define AE_NO_GLOBAL_LOCK               (acpi_status) (0x001A | AE_CODE_ENVIRONMENTAL)
#define AE_LOGICAL_ADDRESS              (acpi_status) (0x001B | AE_CODE_ENVIRONMENTAL)
#define AE_ABORT_METHOD                 (acpi_status) (0x001C | AE_CODE_ENVIRONMENTAL)
#define AE_SAME_HANDLER                 (acpi_status) (0x001D | AE_CODE_ENVIRONMENTAL)
#define AE_WAKE_ONLY_GPE                (acpi_status) (0x001E | AE_CODE_ENVIRONMENTAL)
#define AE_OWNER_ID_LIMIT               (acpi_status) (0x001F | AE_CODE_ENVIRONMENTAL)

#define AE_CODE_ENV_MAX                 0x001F

/*
 * Programmer exceptions
 */
#define AE_BAD_PARAMETER                (acpi_status) (0x0001 | AE_CODE_PROGRAMMER)
#define AE_BAD_CHARACTER                (acpi_status) (0x0002 | AE_CODE_PROGRAMMER)
#define AE_BAD_PATHNAME                 (acpi_status) (0x0003 | AE_CODE_PROGRAMMER)
#define AE_BAD_DATA                     (acpi_status) (0x0004 | AE_CODE_PROGRAMMER)
#define AE_BAD_ADDRESS                  (acpi_status) (0x0005 | AE_CODE_PROGRAMMER)
#define AE_ALIGNMENT                    (acpi_status) (0x0006 | AE_CODE_PROGRAMMER)
#define AE_BAD_HEX_CONSTANT             (acpi_status) (0x0007 | AE_CODE_PROGRAMMER)
#define AE_BAD_OCTAL_CONSTANT           (acpi_status) (0x0008 | AE_CODE_PROGRAMMER)
#define AE_BAD_DECIMAL_CONSTANT         (acpi_status) (0x0009 | AE_CODE_PROGRAMMER)

#define AE_CODE_PGM_MAX                 0x0009

/*
 * Acpi table exceptions
 */
#define AE_BAD_SIGNATURE                (acpi_status) (0x0001 | AE_CODE_ACPI_TABLES)
#define AE_BAD_HEADER                   (acpi_status) (0x0002 | AE_CODE_ACPI_TABLES)
#define AE_BAD_CHECKSUM                 (acpi_status) (0x0003 | AE_CODE_ACPI_TABLES)
#define AE_BAD_VALUE                    (acpi_status) (0x0004 | AE_CODE_ACPI_TABLES)
#define AE_TABLE_NOT_SUPPORTED          (acpi_status) (0x0005 | AE_CODE_ACPI_TABLES)
#define AE_INVALID_TABLE_LENGTH         (acpi_status) (0x0006 | AE_CODE_ACPI_TABLES)

#define AE_CODE_TBL_MAX                 0x0006

/*
 * AML exceptions.  These are caused by problems with
 * the actual AML byte stream
 */
#define AE_AML_ERROR                    (acpi_status) (0x0001 | AE_CODE_AML)
#define AE_AML_PARSE                    (acpi_status) (0x0002 | AE_CODE_AML)
#define AE_AML_BAD_OPCODE               (acpi_status) (0x0003 | AE_CODE_AML)
#define AE_AML_NO_OPERAND               (acpi_status) (0x0004 | AE_CODE_AML)
#define AE_AML_OPERAND_TYPE             (acpi_status) (0x0005 | AE_CODE_AML)
#define AE_AML_OPERAND_VALUE            (acpi_status) (0x0006 | AE_CODE_AML)
#define AE_AML_UNINITIALIZED_LOCAL      (acpi_status) (0x0007 | AE_CODE_AML)
#define AE_AML_UNINITIALIZED_ARG        (acpi_status) (0x0008 | AE_CODE_AML)
#define AE_AML_UNINITIALIZED_ELEMENT    (acpi_status) (0x0009 | AE_CODE_AML)
#define AE_AML_NUMERIC_OVERFLOW         (acpi_status) (0x000A | AE_CODE_AML)
#define AE_AML_REGION_LIMIT             (acpi_status) (0x000B | AE_CODE_AML)
#define AE_AML_BUFFER_LIMIT             (acpi_status) (0x000C | AE_CODE_AML)
#define AE_AML_PACKAGE_LIMIT            (acpi_status) (0x000D | AE_CODE_AML)
#define AE_AML_DIVIDE_BY_ZERO           (acpi_status) (0x000E | AE_CODE_AML)
#define AE_AML_BAD_NAME                 (acpi_status) (0x000F | AE_CODE_AML)
#define AE_AML_NAME_NOT_FOUND           (acpi_status) (0x0010 | AE_CODE_AML)
#define AE_AML_INTERNAL                 (acpi_status) (0x0011 | AE_CODE_AML)
#define AE_AML_INVALID_SPACE_ID         (acpi_status) (0x0012 | AE_CODE_AML)
#define AE_AML_STRING_LIMIT             (acpi_status) (0x0013 | AE_CODE_AML)
#define AE_AML_NO_RETURN_VALUE          (acpi_status) (0x0014 | AE_CODE_AML)
#define AE_AML_METHOD_LIMIT             (acpi_status) (0x0015 | AE_CODE_AML)
#define AE_AML_NOT_OWNER                (acpi_status) (0x0016 | AE_CODE_AML)
#define AE_AML_MUTEX_ORDER              (acpi_status) (0x0017 | AE_CODE_AML)
#define AE_AML_MUTEX_NOT_ACQUIRED       (acpi_status) (0x0018 | AE_CODE_AML)
#define AE_AML_INVALID_RESOURCE_TYPE    (acpi_status) (0x0019 | AE_CODE_AML)
#define AE_AML_INVALID_INDEX            (acpi_status) (0x001A | AE_CODE_AML)
#define AE_AML_REGISTER_LIMIT           (acpi_status) (0x001B | AE_CODE_AML)
#define AE_AML_NO_WHILE                 (acpi_status) (0x001C | AE_CODE_AML)
#define AE_AML_ALIGNMENT                (acpi_status) (0x001D | AE_CODE_AML)
#define AE_AML_NO_RESOURCE_END_TAG      (acpi_status) (0x001E | AE_CODE_AML)
#define AE_AML_BAD_RESOURCE_VALUE       (acpi_status) (0x001F | AE_CODE_AML)
#define AE_AML_CIRCULAR_REFERENCE       (acpi_status) (0x0020 | AE_CODE_AML)
#define AE_AML_BAD_RESOURCE_LENGTH      (acpi_status) (0x0021 | AE_CODE_AML)
#define AE_AML_ILLEGAL_ADDRESS          (acpi_status) (0x0022 | AE_CODE_AML)

#define AE_CODE_AML_MAX                 0x0022

/*
 * Internal exceptions used for control
 */
#define AE_CTRL_RETURN_VALUE            (acpi_status) (0x0001 | AE_CODE_CONTROL)
#define AE_CTRL_PENDING                 (acpi_status) (0x0002 | AE_CODE_CONTROL)
#define AE_CTRL_TERMINATE               (acpi_status) (0x0003 | AE_CODE_CONTROL)
#define AE_CTRL_TRUE                    (acpi_status) (0x0004 | AE_CODE_CONTROL)
#define AE_CTRL_FALSE                   (acpi_status) (0x0005 | AE_CODE_CONTROL)
#define AE_CTRL_DEPTH                   (acpi_status) (0x0006 | AE_CODE_CONTROL)
#define AE_CTRL_END                     (acpi_status) (0x0007 | AE_CODE_CONTROL)
#define AE_CTRL_TRANSFER                (acpi_status) (0x0008 | AE_CODE_CONTROL)
#define AE_CTRL_BREAK                   (acpi_status) (0x0009 | AE_CODE_CONTROL)
#define AE_CTRL_CONTINUE                (acpi_status) (0x000A | AE_CODE_CONTROL)
#define AE_CTRL_SKIP                    (acpi_status) (0x000B | AE_CODE_CONTROL)

#define AE_CODE_CTRL_MAX                0x000B

#ifdef DEFINE_ACPI_GLOBALS

/*
 * String versions of the exception codes above
 * These strings must match the corresponding defines exactly
 */
char const *acpi_gbl_exception_names_env[] = {
	"AE_OK",
	"AE_ERROR",
	"AE_NO_ACPI_TABLES",
	"AE_NO_NAMESPACE",
	"AE_NO_MEMORY",
	"AE_NOT_FOUND",
	"AE_NOT_EXIST",
	"AE_ALREADY_EXISTS",
	"AE_TYPE",
	"AE_NULL_OBJECT",
	"AE_NULL_ENTRY",
	"AE_BUFFER_OVERFLOW",
	"AE_STACK_OVERFLOW",
	"AE_STACK_UNDERFLOW",
	"AE_NOT_IMPLEMENTED",
	"AE_VERSION_MISMATCH",
	"AE_SUPPORT",
	"AE_SHARE",
	"AE_LIMIT",
	"AE_TIME",
	"AE_UNKNOWN_STATUS",
	"AE_ACQUIRE_DEADLOCK",
	"AE_RELEASE_DEADLOCK",
	"AE_NOT_ACQUIRED",
	"AE_ALREADY_ACQUIRED",
	"AE_NO_HARDWARE_RESPONSE",
	"AE_NO_GLOBAL_LOCK",
	"AE_LOGICAL_ADDRESS",
	"AE_ABORT_METHOD",
	"AE_SAME_HANDLER",
	"AE_WAKE_ONLY_GPE",
	"AE_OWNER_ID_LIMIT"
};

char const *acpi_gbl_exception_names_pgm[] = {
	"AE_BAD_PARAMETER",
	"AE_BAD_CHARACTER",
	"AE_BAD_PATHNAME",
	"AE_BAD_DATA",
	"AE_BAD_ADDRESS",
	"AE_ALIGNMENT",
	"AE_BAD_HEX_CONSTANT",
	"AE_BAD_OCTAL_CONSTANT",
	"AE_BAD_DECIMAL_CONSTANT"
};

char const *acpi_gbl_exception_names_tbl[] = {
	"AE_BAD_SIGNATURE",
	"AE_BAD_HEADER",
	"AE_BAD_CHECKSUM",
	"AE_BAD_VALUE",
	"AE_TABLE_NOT_SUPPORTED",
	"AE_INVALID_TABLE_LENGTH"
};

char const *acpi_gbl_exception_names_aml[] = {
	"AE_AML_ERROR",
	"AE_AML_PARSE",
	"AE_AML_BAD_OPCODE",
	"AE_AML_NO_OPERAND",
	"AE_AML_OPERAND_TYPE",
	"AE_AML_OPERAND_VALUE",
	"AE_AML_UNINITIALIZED_LOCAL",
	"AE_AML_UNINITIALIZED_ARG",
	"AE_AML_UNINITIALIZED_ELEMENT",
	"AE_AML_NUMERIC_OVERFLOW",
	"AE_AML_REGION_LIMIT",
	"AE_AML_BUFFER_LIMIT",
	"AE_AML_PACKAGE_LIMIT",
	"AE_AML_DIVIDE_BY_ZERO",
	"AE_AML_BAD_NAME",
	"AE_AML_NAME_NOT_FOUND",
	"AE_AML_INTERNAL",
	"AE_AML_INVALID_SPACE_ID",
	"AE_AML_STRING_LIMIT",
	"AE_AML_NO_RETURN_VALUE",
	"AE_AML_METHOD_LIMIT",
	"AE_AML_NOT_OWNER",
	"AE_AML_MUTEX_ORDER",
	"AE_AML_MUTEX_NOT_ACQUIRED",
	"AE_AML_INVALID_RESOURCE_TYPE",
	"AE_AML_INVALID_INDEX",
	"AE_AML_REGISTER_LIMIT",
	"AE_AML_NO_WHILE",
	"AE_AML_ALIGNMENT",
	"AE_AML_NO_RESOURCE_END_TAG",
	"AE_AML_BAD_RESOURCE_VALUE",
	"AE_AML_CIRCULAR_REFERENCE",
	"AE_AML_BAD_RESOURCE_LENGTH",
	"AE_AML_ILLEGAL_ADDRESS"
};

char const *acpi_gbl_exception_names_ctrl[] = {
	"AE_CTRL_RETURN_VALUE",
	"AE_CTRL_PENDING",
	"AE_CTRL_TERMINATE",
	"AE_CTRL_TRUE",
	"AE_CTRL_FALSE",
	"AE_CTRL_DEPTH",
	"AE_CTRL_END",
	"AE_CTRL_TRANSFER",
	"AE_CTRL_BREAK",
	"AE_CTRL_CONTINUE",
	"AE_CTRL_SKIP"
};

#endif				/* ACPI GLOBALS */

#endif				/* __ACEXCEP_H__ */
/*
 *  Deadline i/o scheduler.
 *
 *  Copyright (C) 2002 Jens Axboe <axboe@kernel.dk>
 */
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
#include <linux/bio.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/rbtree.h>

/*
 * See Documentation/block/deadline-iosched.txt
 */
static const int read_expire = HZ / 2;  /* max time before a read is submitted. */
static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
static const int writes_starved = 2;    /* max times reads can starve a write */
static const int fifo_batch = 16;       /* # of sequential requests treated as one
				     by the above parameters. For throughput. */

struct deadline_data {
	/*
	 * run time data
	 */

	/*
	 * requests (deadline_rq s) are present on both sort_list and fifo_list
	 */
	struct rb_root sort_list[2];	
	struct list_head fifo_list[2];

	/*
	 * next in sort order. read, write or both are NULL
	 */
	struct request *next_rq[2];
	unsigned int batching;		/* number of sequential requests made */
	sector_t last_sector;		/* head position */
	unsigned int starved;		/* times reads have starved writes */

	/*
	 * settings that change how the i/o scheduler behaves
	 */
	int fifo_expire[2];
	int fifo_batch;
	int writes_starved;
	int front_merges;
};

static void deadline_move_request(struct deadline_data *, struct request *);

static inline struct rb_root *
deadline_rb_root(struct deadline_data *dd, struct request *rq)
{
	return &dd->sort_list[rq_data_dir(rq)];
}

/*
 * get the request after `rq' in sector-sorted order
 */
static inline struct request *
deadline_latter_request(struct request *rq)
{
	struct rb_node *node = rb_next(&rq->rb_node);

	if (node)
		return rb_entry_rq(node);

	return NULL;
}

static void
deadline_add_rq_rb(struct deadline_data *dd, struct request *rq)
{
	struct rb_root *root = deadline_rb_root(dd, rq);
	struct request *__alias;

	while (unlikely(__alias = elv_rb_add(root, rq)))
		deadline_move_request(dd, __alias);
}

static inline void
deadline_del_rq_rb(struct deadline_data *dd, struct request *rq)
{
	const int data_dir = rq_data_dir(rq);

	if (dd->next_rq[data_dir] == rq)
		dd->next_rq[data_dir] = deadline_latter_request(rq);

	elv_rb_del(deadline_rb_root(dd, rq), rq);
}

/*
 * add rq to rbtree and fifo
 */
static void
deadline_add_request(struct request_queue *q, struct request *rq)
{
	struct deadline_data *dd = q->elevator->elevator_data;
	const int data_dir = rq_data_dir(rq);

	deadline_add_rq_rb(dd, rq);

	/*
	 * set expire time and add to fifo list
	 */
	rq_set_fifo_time(rq, jiffies + dd->fifo_expire[data_dir]);
	list_add_tail(&rq->queuelist, &dd->fifo_list[data_dir]);
}

/*
 * remove rq from rbtree and fifo.
 */
static void deadline_remove_request(struct request_queue *q, struct request *rq)
{
	struct deadline_data *dd = q->elevator->elevator_data;

	rq_fifo_clear(rq);
	deadline_del_rq_rb(dd, rq);
}

static int
deadline_merge(struct request_queue *q, struct request **req, struct bio *bio)
{
	struct deadline_data *dd = q->elevator->elevator_data;
	struct request *__rq;
	int ret;

	/*
	 * check for front merge
	 */
	if (dd->front_merges) {
		sector_t sector = bio->bi_sector + bio_sectors(bio);

		__rq = elv_rb_find(&dd->sort_list[bio_data_dir(bio)], sector);
		if (__rq) {
			BUG_ON(sector != __rq->sector);

			if (elv_rq_merge_ok(__rq, bio)) {
				ret = ELEVATOR_FRONT_MERGE;
				goto out;
			}
		}
	}

	return ELEVATOR_NO_MERGE;
out:
	*req = __rq;
	return ret;
}

static void deadline_merged_request(struct request_queue *q,
				    struct request *req, int type)
{
	struct deadline_data *dd = q->elevator->elevator_data;

	/*
	 * if the merge was a front merge, we need to reposition request
	 */
	if (type == ELEVATOR_FRONT_MERGE) {
		elv_rb_del(deadline_rb_root(dd, req), req);
		deadline_add_rq_rb(dd, req);
	}
}

static void
deadline_merged_requests(struct request_queue *q, struct request *req,
			 struct request *next)
{
	/*
	 * if next expires before rq, assign its expire time to rq
	 * and move into next position (next will be deleted) in fifo
	 */
	if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
		if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {
			list_move(&req->queuelist, &next->queuelist);
			rq_set_fifo_time(req, rq_fifo_time(next));
		}
	}

	/*
	 * kill knowledge of next, this one is a goner
	 */
	deadline_remove_request(q, next);
}

/*
 * move request from sort list to dispatch queue.
 */
static inline void
deadline_move_to_dispatch(struct deadline_data *dd, struct request *rq)
{
	struct request_queue *q = rq->q;

	deadline_remove_request(q, rq);
	elv_dispatch_add_tail(q, rq);
}

/*
 * move an entry to dispatch queue
 */
static void
deadline_move_request(struct deadline_data *dd, struct request *rq)
{
	const int data_dir = rq_data_dir(rq);

	dd->next_rq[READ] = NULL;
	dd->next_rq[WRITE] = NULL;
	dd->next_rq[data_dir] = deadline_latter_request(rq);

	dd->last_sector = rq_end_sector(rq);

	/*
	 * take it off the sort and fifo list, move
	 * to dispatch queue
	 */
	deadline_move_to_dispatch(dd, rq);
}

/*
 * deadline_check_fifo returns 0 if there are no expired requests on the fifo,
 * 1 otherwise. Requires !list_empty(&dd->fifo_list[data_dir])
 */
static inline int deadline_check_fifo(struct deadline_data *dd, int ddir)
{
	struct request *rq = rq_entry_fifo(dd->fifo_list[ddir].next);

	/*
	 * rq is expired!
	 */
	if (time_after(jiffies, rq_fifo_time(rq)))
		return 1;

	return 0;
}

/*
 * deadline_dispatch_requests selects the best request according to
 * read/write expire, fifo_batch, etc
 */
static int deadline_dispatch_requests(struct request_queue *q, int force)
{
	struct deadline_data *dd = q->elevator->elevator_data;
	const int reads = !list_empty(&dd->fifo_list[READ]);
	const int writes = !list_empty(&dd->fifo_list[WRITE]);
	struct request *rq;
	int data_dir;

	/*
	 * batches are currently reads XOR writes
	 */
	if (dd->next_rq[WRITE])
		rq = dd->next_rq[WRITE];
	else
		rq = dd->next_rq[READ];

	if (rq && dd->batching < dd->fifo_batch)
		/* we have a next request are still entitled to batch */
		goto dispatch_request;

	/*
	 * at this point we are not running a batch. select the appropriate
	 * data direction (read / write)
	 */

	if (reads) {
		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[READ]));

		if (writes && (dd->starved++ >= dd->writes_starved))
			goto dispatch_writes;

		data_dir = READ;

		goto dispatch_find_request;
	}

	/*
	 * there are either no reads or writes have been starved
	 */

	if (writes) {
dispatch_writes:
		BUG_ON(RB_EMPTY_ROOT(&dd->sort_list[WRITE]));

		dd->starved = 0;

		data_dir = WRITE;

		goto dispatch_find_request;
	}

	return 0;

dispatch_find_request:
	/*
	 * we are not running a batch, find best request for selected data_dir
	 */
	if (deadline_check_fifo(dd, data_dir) || !dd->next_rq[data_dir]) {
		/*
		 * A deadline has expired, the last request was in the other
		 * direction, or we have run out of higher-sectored requests.
		 * Start again from the request with the earliest expiry time.
		 */
		rq = rq_entry_fifo(dd->fifo_list[data_dir].next);
	} else {
		/*
		 * The last req was the same dir and we have a next request in
		 * sort order. No expired requests so continue on from here.
		 */
		rq = dd->next_rq[data_dir];
	}

	dd->batching = 0;

dispatch_request:
	/*
	 * rq is the selected appropriate request.
	 */
	dd->batching++;
	deadline_move_request(dd, rq);

	return 1;
}

static int deadline_queue_empty(struct request_queue *q)
{
	struct deadline_data *dd = q->elevator->elevator_data;

	return list_empty(&dd->fifo_list[WRITE])
		&& list_empty(&dd->fifo_list[READ]);
}

static void deadline_exit_queue(struct elevator_queue *e)
{
	struct deadline_data *dd = e->elevator_data;

	BUG_ON(!list_empty(&dd->fifo_list[READ]));
	BUG_ON(!list_empty(&dd->fifo_list[WRITE]));

	kfree(dd);
}

/*
 * initialize elevator private data (deadline_data).
 */
static void *deadline_init_queue(struct request_queue *q)
{
	struct deadline_data *dd;

	dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node);
	if (!dd)
		return NULL;

	INIT_LIST_HEAD(&dd->fifo_list[READ]);
	INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
	dd->sort_list[READ] = RB_ROOT;
	dd->sort_list[WRITE] = RB_ROOT;
	dd->fifo_expire[READ] = read_expire;
	dd->fifo_expire[WRITE] = write_expire;
	dd->writes_starved = writes_starved;
	dd->front_merges = 1;
	dd->fifo_batch = fifo_batch;
	return dd;
}

/*
 * sysfs parts below
 */

static ssize_t
deadline_var_show(int var, char *page)
{
	return sprintf(page, "%d\n", var);
}

static ssize_t
deadline_var_store(int *var, const char *page, size_t count)
{
	char *p = (char *) page;

	*var = simple_strtol(p, &p, 10);
	return count;
}

#define SHOW_FUNCTION(__FUNC, __VAR, __CONV)				\
static ssize_t __FUNC(struct elevator_queue *e, char *page)		\
{									\
	struct deadline_data *dd = e->elevator_data;			\
	int __data = __VAR;						\
	if (__CONV)							\
		__data = jiffies_to_msecs(__data);			\
	return deadline_var_show(__data, (page));			\
}
SHOW_FUNCTION(deadline_read_expire_show, dd->fifo_expire[READ], 1);
SHOW_FUNCTION(deadline_write_expire_show, dd->fifo_expire[WRITE], 1);
SHOW_FUNCTION(deadline_writes_starved_show, dd->writes_starved, 0);
SHOW_FUNCTION(deadline_front_merges_show, dd->front_merges, 0);
SHOW_FUNCTION(deadline_fifo_batch_show, dd->fifo_batch, 0);
#undef SHOW_FUNCTION

#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)			\
static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)	\
{									\
	struct deadline_data *dd = e->elevator_data;			\
	int __data;							\
	int ret = deadline_var_store(&__data, (page), count);		\
	if (__data < (MIN))						\
		__data = (MIN);						\
	else if (__data > (MAX))					\
		__data = (MAX);						\
	if (__CONV)							\
		*(__PTR) = msecs_to_jiffies(__data);			\
	else								\
		*(__PTR) = __data;					\
	return ret;							\
}
STORE_FUNCTION(deadline_read_expire_store, &dd->fifo_expire[READ], 0, INT_MAX, 1);
STORE_FUNCTION(deadline_write_expire_store, &dd->fifo_expire[WRITE], 0, INT_MAX, 1);
STORE_FUNCTION(deadline_writes_starved_store, &dd->writes_starved, INT_MIN, INT_MAX, 0);
STORE_FUNCTION(deadline_front_merges_store, &dd->front_merges, 0, 1, 0);
STORE_FUNCTION(deadline_fifo_batch_store, &dd->fifo_batch, 0, INT_MAX, 0);
#undef STORE_FUNCTION

#define DD_ATTR(name) \
	__ATTR(name, S_IRUGO|S_IWUSR, deadline_##name##_show, \
				      deadline_##name##_store)

static struct elv_fs_entry deadline_attrs[] = {
	DD_ATTR(read_expire),
	DD_ATTR(write_expire),
	DD_ATTR(writes_starved),
	DD_ATTR(front_merges),
	DD_ATTR(fifo_batch),
	__ATTR_NULL
};

static struct elevator_type iosched_deadline = {
	.ops = {
		.elevator_merge_fn = 		deadline_merge,
		.elevator_merged_fn =		deadline_merged_request,
		.elevator_merge_req_fn =	deadline_merged_requests,
		.elevator_dispatch_fn =		deadline_dispatch_requests,
		.elevator_add_req_fn =		deadline_add_request,
		.elevator_queue_empty_fn =	deadline_queue_empty,
		.elevator_former_req_fn =	elv_rb_former_request,
		.elevator_latter_req_fn =	elv_rb_latter_request,
		.elevator_init_fn =		deadline_init_queue,
		.elevator_exit_fn =		deadline_exit_queue,
	},

	.elevator_attrs = deadline_attrs,
	.elevator_name = "deadline",
	.elevator_owner = THIS_MODULE,
};

static int __init deadline_init(void)
{
	elv_register(&iosched_deadline);

	return 0;
}

static void __exit deadline_exit(void)
{
	elv_unregister(&iosched_deadline);
}

module_init(deadline_init);
module_exit(deadline_exit);

MODULE_AUTHOR("Jens Axboe");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("deadline IO scheduler");