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Jens Axboe86db1e22008-01-29 14:53:40 +01001/*
2 * Functions related to setting various queue properties from drivers
3 */
4#include <linux/kernel.h>
5#include <linux/module.h>
6#include <linux/init.h>
7#include <linux/bio.h>
8#include <linux/blkdev.h>
9#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
Martin K. Petersen70dd5bf2009-07-31 11:49:12 -040010#include <linux/gcd.h>
Martin K. Petersen2cda2722010-03-15 12:46:51 +010011#include <linux/lcm.h>
Randy Dunlapad5ebd22009-11-11 13:47:45 +010012#include <linux/jiffies.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090013#include <linux/gfp.h>
Jens Axboe86db1e22008-01-29 14:53:40 +010014
15#include "blk.h"
16
Jens Axboe6728cb02008-01-31 13:03:55 +010017unsigned long blk_max_low_pfn;
Jens Axboe86db1e22008-01-29 14:53:40 +010018EXPORT_SYMBOL(blk_max_low_pfn);
Jens Axboe6728cb02008-01-31 13:03:55 +010019
20unsigned long blk_max_pfn;
Jens Axboe86db1e22008-01-29 14:53:40 +010021
22/**
23 * blk_queue_prep_rq - set a prepare_request function for queue
24 * @q: queue
25 * @pfn: prepare_request function
26 *
27 * It's possible for a queue to register a prepare_request callback which
28 * is invoked before the request is handed to the request_fn. The goal of
29 * the function is to prepare a request for I/O, it can be used to build a
30 * cdb from the request data for instance.
31 *
32 */
33void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
34{
35 q->prep_rq_fn = pfn;
36}
Jens Axboe86db1e22008-01-29 14:53:40 +010037EXPORT_SYMBOL(blk_queue_prep_rq);
38
39/**
James Bottomley28018c22010-07-01 19:49:17 +090040 * blk_queue_unprep_rq - set an unprepare_request function for queue
41 * @q: queue
42 * @ufn: unprepare_request function
43 *
44 * It's possible for a queue to register an unprepare_request callback
45 * which is invoked before the request is finally completed. The goal
46 * of the function is to deallocate any data that was allocated in the
47 * prepare_request callback.
48 *
49 */
50void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
51{
52 q->unprep_rq_fn = ufn;
53}
54EXPORT_SYMBOL(blk_queue_unprep_rq);
55
56/**
Jens Axboe86db1e22008-01-29 14:53:40 +010057 * blk_queue_merge_bvec - set a merge_bvec function for queue
58 * @q: queue
59 * @mbfn: merge_bvec_fn
60 *
61 * Usually queues have static limitations on the max sectors or segments that
62 * we can put in a request. Stacking drivers may have some settings that
63 * are dynamic, and thus we have to query the queue whether it is ok to
64 * add a new bio_vec to a bio at a given offset or not. If the block device
65 * has such limitations, it needs to register a merge_bvec_fn to control
66 * the size of bio's sent to it. Note that a block device *must* allow a
67 * single page to be added to an empty bio. The block device driver may want
68 * to use the bio_split() function to deal with these bio's. By default
69 * no merge_bvec_fn is defined for a queue, and only the fixed limits are
70 * honored.
71 */
72void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
73{
74 q->merge_bvec_fn = mbfn;
75}
Jens Axboe86db1e22008-01-29 14:53:40 +010076EXPORT_SYMBOL(blk_queue_merge_bvec);
77
78void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
79{
80 q->softirq_done_fn = fn;
81}
Jens Axboe86db1e22008-01-29 14:53:40 +010082EXPORT_SYMBOL(blk_queue_softirq_done);
83
Jens Axboe242f9dc2008-09-14 05:55:09 -070084void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
85{
86 q->rq_timeout = timeout;
87}
88EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
89
90void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
91{
92 q->rq_timed_out_fn = fn;
93}
94EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
95
Kiyoshi Uedaef9e3fa2008-10-01 16:12:15 +020096void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
97{
98 q->lld_busy_fn = fn;
99}
100EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
101
Jens Axboe86db1e22008-01-29 14:53:40 +0100102/**
Martin K. Petersene475bba2009-06-16 08:23:52 +0200103 * blk_set_default_limits - reset limits to default values
Randy Dunlapf740f5ca2009-06-19 09:18:32 +0200104 * @lim: the queue_limits structure to reset
Martin K. Petersene475bba2009-06-16 08:23:52 +0200105 *
106 * Description:
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100107 * Returns a queue_limit struct to its default state.
Martin K. Petersene475bba2009-06-16 08:23:52 +0200108 */
109void blk_set_default_limits(struct queue_limits *lim)
110{
Martin K. Petersen8a783622010-02-26 00:20:39 -0500111 lim->max_segments = BLK_MAX_SEGMENTS;
Martin K. Petersen13f05c82010-09-10 20:50:10 +0200112 lim->max_integrity_segments = 0;
Martin K. Petersene475bba2009-06-16 08:23:52 +0200113 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
Martin K. Peterseneb28d312010-02-26 00:20:37 -0500114 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100115 lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
Jens Axboe762380a2014-06-05 13:38:39 -0600116 lim->chunk_sectors = 0;
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400117 lim->max_write_same_sectors = 0;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100118 lim->max_discard_sectors = 0;
119 lim->discard_granularity = 0;
120 lim->discard_alignment = 0;
121 lim->discard_misaligned = 0;
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100122 lim->discard_zeroes_data = 0;
Martin K. Petersene475bba2009-06-16 08:23:52 +0200123 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
Martin K. Petersen3a02c8e2009-06-18 09:56:03 +0200124 lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
Martin K. Petersene475bba2009-06-16 08:23:52 +0200125 lim->alignment_offset = 0;
126 lim->io_opt = 0;
127 lim->misaligned = 0;
Martin K. Petersene692cb62010-12-01 19:41:49 +0100128 lim->cluster = 1;
Martin K. Petersene475bba2009-06-16 08:23:52 +0200129}
130EXPORT_SYMBOL(blk_set_default_limits);
131
132/**
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100133 * blk_set_stacking_limits - set default limits for stacking devices
134 * @lim: the queue_limits structure to reset
135 *
136 * Description:
137 * Returns a queue_limit struct to its default state. Should be used
138 * by stacking drivers like DM that have no internal limits.
139 */
140void blk_set_stacking_limits(struct queue_limits *lim)
141{
142 blk_set_default_limits(lim);
143
144 /* Inherit limits from component devices */
145 lim->discard_zeroes_data = 1;
146 lim->max_segments = USHRT_MAX;
147 lim->max_hw_sectors = UINT_MAX;
Mike Snitzerd82ae522013-10-18 09:44:49 -0600148 lim->max_segment_size = UINT_MAX;
Mike Snitzerfe86cdc2012-08-01 10:44:28 +0200149 lim->max_sectors = UINT_MAX;
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400150 lim->max_write_same_sectors = UINT_MAX;
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100151}
152EXPORT_SYMBOL(blk_set_stacking_limits);
153
154/**
Jens Axboe86db1e22008-01-29 14:53:40 +0100155 * blk_queue_make_request - define an alternate make_request function for a device
156 * @q: the request queue for the device to be affected
157 * @mfn: the alternate make_request function
158 *
159 * Description:
160 * The normal way for &struct bios to be passed to a device
161 * driver is for them to be collected into requests on a request
162 * queue, and then to allow the device driver to select requests
163 * off that queue when it is ready. This works well for many block
164 * devices. However some block devices (typically virtual devices
165 * such as md or lvm) do not benefit from the processing on the
166 * request queue, and are served best by having the requests passed
167 * directly to them. This can be achieved by providing a function
168 * to blk_queue_make_request().
169 *
170 * Caveat:
171 * The driver that does this *must* be able to deal appropriately
172 * with buffers in "highmemory". This can be accomplished by either calling
173 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
174 * blk_queue_bounce() to create a buffer in normal memory.
175 **/
Jens Axboe6728cb02008-01-31 13:03:55 +0100176void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
Jens Axboe86db1e22008-01-29 14:53:40 +0100177{
178 /*
179 * set defaults
180 */
181 q->nr_requests = BLKDEV_MAX_RQ;
Milan Broz0e435ac2008-12-03 12:55:08 +0100182
Jens Axboe86db1e22008-01-29 14:53:40 +0100183 q->make_request_fn = mfn;
Jens Axboe86db1e22008-01-29 14:53:40 +0100184 blk_queue_dma_alignment(q, 511);
185 blk_queue_congestion_threshold(q);
186 q->nr_batching = BLK_BATCH_REQ;
187
Martin K. Petersene475bba2009-06-16 08:23:52 +0200188 blk_set_default_limits(&q->limits);
189
Jens Axboe86db1e22008-01-29 14:53:40 +0100190 /*
191 * by default assume old behaviour and bounce for any highmem page
192 */
193 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
194}
Jens Axboe86db1e22008-01-29 14:53:40 +0100195EXPORT_SYMBOL(blk_queue_make_request);
196
197/**
198 * blk_queue_bounce_limit - set bounce buffer limit for queue
Tejun Heocd0aca22009-04-15 22:10:25 +0900199 * @q: the request queue for the device
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100200 * @max_addr: the maximum address the device can handle
Jens Axboe86db1e22008-01-29 14:53:40 +0100201 *
202 * Description:
203 * Different hardware can have different requirements as to what pages
204 * it can do I/O directly to. A low level driver can call
205 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100206 * buffers for doing I/O to pages residing above @max_addr.
Jens Axboe86db1e22008-01-29 14:53:40 +0100207 **/
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100208void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
Jens Axboe86db1e22008-01-29 14:53:40 +0100209{
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100210 unsigned long b_pfn = max_addr >> PAGE_SHIFT;
Jens Axboe86db1e22008-01-29 14:53:40 +0100211 int dma = 0;
212
213 q->bounce_gfp = GFP_NOIO;
214#if BITS_PER_LONG == 64
Tejun Heocd0aca22009-04-15 22:10:25 +0900215 /*
216 * Assume anything <= 4GB can be handled by IOMMU. Actually
217 * some IOMMUs can handle everything, but I don't know of a
218 * way to test this here.
219 */
220 if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
Jens Axboe86db1e22008-01-29 14:53:40 +0100221 dma = 1;
Malahal Naineniefb012b32010-10-01 14:45:27 +0200222 q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
Jens Axboe86db1e22008-01-29 14:53:40 +0100223#else
Jens Axboe6728cb02008-01-31 13:03:55 +0100224 if (b_pfn < blk_max_low_pfn)
Jens Axboe86db1e22008-01-29 14:53:40 +0100225 dma = 1;
Malahal Nainenic49825f2010-09-24 20:25:49 +0200226 q->limits.bounce_pfn = b_pfn;
Jens Axboe260a67a2010-10-01 14:42:43 +0200227#endif
Jens Axboe86db1e22008-01-29 14:53:40 +0100228 if (dma) {
229 init_emergency_isa_pool();
230 q->bounce_gfp = GFP_NOIO | GFP_DMA;
Jens Axboe260a67a2010-10-01 14:42:43 +0200231 q->limits.bounce_pfn = b_pfn;
Jens Axboe86db1e22008-01-29 14:53:40 +0100232 }
233}
Jens Axboe86db1e22008-01-29 14:53:40 +0100234EXPORT_SYMBOL(blk_queue_bounce_limit);
235
236/**
Mike Snitzer72d4cd92010-12-17 08:34:20 +0100237 * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request
238 * @limits: the queue limits
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500239 * @max_hw_sectors: max hardware sectors in the usual 512b unit
Jens Axboe86db1e22008-01-29 14:53:40 +0100240 *
241 * Description:
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500242 * Enables a low level driver to set a hard upper limit,
243 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
244 * the device driver based upon the combined capabilities of I/O
245 * controller and storage device.
246 *
247 * max_sectors is a soft limit imposed by the block layer for
248 * filesystem type requests. This value can be overridden on a
249 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
250 * The soft limit can not exceed max_hw_sectors.
Jens Axboe86db1e22008-01-29 14:53:40 +0100251 **/
Mike Snitzer72d4cd92010-12-17 08:34:20 +0100252void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors)
Jens Axboe86db1e22008-01-29 14:53:40 +0100253{
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500254 if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
255 max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
Harvey Harrison24c03d42008-05-01 04:35:17 -0700256 printk(KERN_INFO "%s: set to minimum %d\n",
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500257 __func__, max_hw_sectors);
Jens Axboe86db1e22008-01-29 14:53:40 +0100258 }
259
Mike Snitzer72d4cd92010-12-17 08:34:20 +0100260 limits->max_hw_sectors = max_hw_sectors;
261 limits->max_sectors = min_t(unsigned int, max_hw_sectors,
262 BLK_DEF_MAX_SECTORS);
263}
264EXPORT_SYMBOL(blk_limits_max_hw_sectors);
265
266/**
267 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
268 * @q: the request queue for the device
269 * @max_hw_sectors: max hardware sectors in the usual 512b unit
270 *
271 * Description:
272 * See description for blk_limits_max_hw_sectors().
273 **/
274void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
275{
276 blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
Jens Axboe86db1e22008-01-29 14:53:40 +0100277}
Martin K. Petersen086fa5f2010-02-26 00:20:38 -0500278EXPORT_SYMBOL(blk_queue_max_hw_sectors);
Jens Axboe86db1e22008-01-29 14:53:40 +0100279
280/**
Jens Axboe762380a2014-06-05 13:38:39 -0600281 * blk_queue_chunk_sectors - set size of the chunk for this queue
282 * @q: the request queue for the device
283 * @chunk_sectors: chunk sectors in the usual 512b unit
284 *
285 * Description:
286 * If a driver doesn't want IOs to cross a given chunk size, it can set
287 * this limit and prevent merging across chunks. Note that the chunk size
Jens Axboe58a49152014-06-10 12:53:56 -0600288 * must currently be a power-of-2 in sectors. Also note that the block
289 * layer must accept a page worth of data at any offset. So if the
290 * crossing of chunks is a hard limitation in the driver, it must still be
291 * prepared to split single page bios.
Jens Axboe762380a2014-06-05 13:38:39 -0600292 **/
293void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
294{
295 BUG_ON(!is_power_of_2(chunk_sectors));
296 q->limits.chunk_sectors = chunk_sectors;
297}
298EXPORT_SYMBOL(blk_queue_chunk_sectors);
299
300/**
Christoph Hellwig67efc922009-09-30 13:54:20 +0200301 * blk_queue_max_discard_sectors - set max sectors for a single discard
302 * @q: the request queue for the device
Randy Dunlapc7ebf062009-10-12 08:20:47 +0200303 * @max_discard_sectors: maximum number of sectors to discard
Christoph Hellwig67efc922009-09-30 13:54:20 +0200304 **/
305void blk_queue_max_discard_sectors(struct request_queue *q,
306 unsigned int max_discard_sectors)
307{
308 q->limits.max_discard_sectors = max_discard_sectors;
309}
310EXPORT_SYMBOL(blk_queue_max_discard_sectors);
311
312/**
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400313 * blk_queue_max_write_same_sectors - set max sectors for a single write same
314 * @q: the request queue for the device
315 * @max_write_same_sectors: maximum number of sectors to write per command
316 **/
317void blk_queue_max_write_same_sectors(struct request_queue *q,
318 unsigned int max_write_same_sectors)
319{
320 q->limits.max_write_same_sectors = max_write_same_sectors;
321}
322EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
323
324/**
Martin K. Petersen8a783622010-02-26 00:20:39 -0500325 * blk_queue_max_segments - set max hw segments for a request for this queue
Jens Axboe86db1e22008-01-29 14:53:40 +0100326 * @q: the request queue for the device
327 * @max_segments: max number of segments
328 *
329 * Description:
330 * Enables a low level driver to set an upper limit on the number of
Martin K. Petersen8a783622010-02-26 00:20:39 -0500331 * hw data segments in a request.
Jens Axboe86db1e22008-01-29 14:53:40 +0100332 **/
Martin K. Petersen8a783622010-02-26 00:20:39 -0500333void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
Jens Axboe86db1e22008-01-29 14:53:40 +0100334{
335 if (!max_segments) {
336 max_segments = 1;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700337 printk(KERN_INFO "%s: set to minimum %d\n",
338 __func__, max_segments);
Jens Axboe86db1e22008-01-29 14:53:40 +0100339 }
340
Martin K. Petersen8a783622010-02-26 00:20:39 -0500341 q->limits.max_segments = max_segments;
Jens Axboe86db1e22008-01-29 14:53:40 +0100342}
Martin K. Petersen8a783622010-02-26 00:20:39 -0500343EXPORT_SYMBOL(blk_queue_max_segments);
Jens Axboe86db1e22008-01-29 14:53:40 +0100344
345/**
346 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
347 * @q: the request queue for the device
348 * @max_size: max size of segment in bytes
349 *
350 * Description:
351 * Enables a low level driver to set an upper limit on the size of a
352 * coalesced segment
353 **/
354void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
355{
356 if (max_size < PAGE_CACHE_SIZE) {
357 max_size = PAGE_CACHE_SIZE;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700358 printk(KERN_INFO "%s: set to minimum %d\n",
359 __func__, max_size);
Jens Axboe86db1e22008-01-29 14:53:40 +0100360 }
361
Martin K. Petersen025146e2009-05-22 17:17:51 -0400362 q->limits.max_segment_size = max_size;
Jens Axboe86db1e22008-01-29 14:53:40 +0100363}
Jens Axboe86db1e22008-01-29 14:53:40 +0100364EXPORT_SYMBOL(blk_queue_max_segment_size);
365
366/**
Martin K. Petersene1defc42009-05-22 17:17:49 -0400367 * blk_queue_logical_block_size - set logical block size for the queue
Jens Axboe86db1e22008-01-29 14:53:40 +0100368 * @q: the request queue for the device
Martin K. Petersene1defc42009-05-22 17:17:49 -0400369 * @size: the logical block size, in bytes
Jens Axboe86db1e22008-01-29 14:53:40 +0100370 *
371 * Description:
Martin K. Petersene1defc42009-05-22 17:17:49 -0400372 * This should be set to the lowest possible block size that the
373 * storage device can address. The default of 512 covers most
374 * hardware.
Jens Axboe86db1e22008-01-29 14:53:40 +0100375 **/
Martin K. Petersene1defc42009-05-22 17:17:49 -0400376void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
Jens Axboe86db1e22008-01-29 14:53:40 +0100377{
Martin K. Petersen025146e2009-05-22 17:17:51 -0400378 q->limits.logical_block_size = size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400379
380 if (q->limits.physical_block_size < size)
381 q->limits.physical_block_size = size;
382
383 if (q->limits.io_min < q->limits.physical_block_size)
384 q->limits.io_min = q->limits.physical_block_size;
Jens Axboe86db1e22008-01-29 14:53:40 +0100385}
Martin K. Petersene1defc42009-05-22 17:17:49 -0400386EXPORT_SYMBOL(blk_queue_logical_block_size);
Jens Axboe86db1e22008-01-29 14:53:40 +0100387
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400388/**
389 * blk_queue_physical_block_size - set physical block size for the queue
390 * @q: the request queue for the device
391 * @size: the physical block size, in bytes
392 *
393 * Description:
394 * This should be set to the lowest possible sector size that the
395 * hardware can operate on without reverting to read-modify-write
396 * operations.
397 */
Martin K. Petersen892b6f92010-10-13 21:18:03 +0200398void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400399{
400 q->limits.physical_block_size = size;
401
402 if (q->limits.physical_block_size < q->limits.logical_block_size)
403 q->limits.physical_block_size = q->limits.logical_block_size;
404
405 if (q->limits.io_min < q->limits.physical_block_size)
406 q->limits.io_min = q->limits.physical_block_size;
407}
408EXPORT_SYMBOL(blk_queue_physical_block_size);
409
410/**
411 * blk_queue_alignment_offset - set physical block alignment offset
412 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700413 * @offset: alignment offset in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400414 *
415 * Description:
416 * Some devices are naturally misaligned to compensate for things like
417 * the legacy DOS partition table 63-sector offset. Low-level drivers
418 * should call this function for devices whose first sector is not
419 * naturally aligned.
420 */
421void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
422{
423 q->limits.alignment_offset =
424 offset & (q->limits.physical_block_size - 1);
425 q->limits.misaligned = 0;
426}
427EXPORT_SYMBOL(blk_queue_alignment_offset);
428
429/**
Martin K. Petersen7c958e32009-07-31 11:49:11 -0400430 * blk_limits_io_min - set minimum request size for a device
431 * @limits: the queue limits
432 * @min: smallest I/O size in bytes
433 *
434 * Description:
435 * Some devices have an internal block size bigger than the reported
436 * hardware sector size. This function can be used to signal the
437 * smallest I/O the device can perform without incurring a performance
438 * penalty.
439 */
440void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
441{
442 limits->io_min = min;
443
444 if (limits->io_min < limits->logical_block_size)
445 limits->io_min = limits->logical_block_size;
446
447 if (limits->io_min < limits->physical_block_size)
448 limits->io_min = limits->physical_block_size;
449}
450EXPORT_SYMBOL(blk_limits_io_min);
451
452/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400453 * blk_queue_io_min - set minimum request size for the queue
454 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700455 * @min: smallest I/O size in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400456 *
457 * Description:
Martin K. Petersen7e5f5fb2009-07-31 11:49:13 -0400458 * Storage devices may report a granularity or preferred minimum I/O
459 * size which is the smallest request the device can perform without
460 * incurring a performance penalty. For disk drives this is often the
461 * physical block size. For RAID arrays it is often the stripe chunk
462 * size. A properly aligned multiple of minimum_io_size is the
463 * preferred request size for workloads where a high number of I/O
464 * operations is desired.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400465 */
466void blk_queue_io_min(struct request_queue *q, unsigned int min)
467{
Martin K. Petersen7c958e32009-07-31 11:49:11 -0400468 blk_limits_io_min(&q->limits, min);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400469}
470EXPORT_SYMBOL(blk_queue_io_min);
471
472/**
Martin K. Petersen3c5820c2009-09-11 21:54:52 +0200473 * blk_limits_io_opt - set optimal request size for a device
474 * @limits: the queue limits
475 * @opt: smallest I/O size in bytes
476 *
477 * Description:
478 * Storage devices may report an optimal I/O size, which is the
479 * device's preferred unit for sustained I/O. This is rarely reported
480 * for disk drives. For RAID arrays it is usually the stripe width or
481 * the internal track size. A properly aligned multiple of
482 * optimal_io_size is the preferred request size for workloads where
483 * sustained throughput is desired.
484 */
485void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
486{
487 limits->io_opt = opt;
488}
489EXPORT_SYMBOL(blk_limits_io_opt);
490
491/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400492 * blk_queue_io_opt - set optimal request size for the queue
493 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700494 * @opt: optimal request size in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400495 *
496 * Description:
Martin K. Petersen7e5f5fb2009-07-31 11:49:13 -0400497 * Storage devices may report an optimal I/O size, which is the
498 * device's preferred unit for sustained I/O. This is rarely reported
499 * for disk drives. For RAID arrays it is usually the stripe width or
500 * the internal track size. A properly aligned multiple of
501 * optimal_io_size is the preferred request size for workloads where
502 * sustained throughput is desired.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400503 */
504void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
505{
Martin K. Petersen3c5820c2009-09-11 21:54:52 +0200506 blk_limits_io_opt(&q->limits, opt);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400507}
508EXPORT_SYMBOL(blk_queue_io_opt);
509
Jens Axboe86db1e22008-01-29 14:53:40 +0100510/**
511 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
512 * @t: the stacking driver (top)
513 * @b: the underlying device (bottom)
514 **/
515void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
516{
Martin K. Petersenfef24662009-07-31 11:49:10 -0400517 blk_stack_limits(&t->limits, &b->limits, 0);
Jens Axboe86db1e22008-01-29 14:53:40 +0100518}
Jens Axboe86db1e22008-01-29 14:53:40 +0100519EXPORT_SYMBOL(blk_queue_stack_limits);
520
521/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400522 * blk_stack_limits - adjust queue_limits for stacked devices
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100523 * @t: the stacking driver limits (top device)
524 * @b: the underlying queue limits (bottom, component device)
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500525 * @start: first data sector within component device
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400526 *
527 * Description:
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100528 * This function is used by stacking drivers like MD and DM to ensure
529 * that all component devices have compatible block sizes and
530 * alignments. The stacking driver must provide a queue_limits
531 * struct (top) and then iteratively call the stacking function for
532 * all component (bottom) devices. The stacking function will
533 * attempt to combine the values and ensure proper alignment.
534 *
535 * Returns 0 if the top and bottom queue_limits are compatible. The
536 * top device's block sizes and alignment offsets may be adjusted to
537 * ensure alignment with the bottom device. If no compatible sizes
538 * and alignments exist, -1 is returned and the resulting top
539 * queue_limits will have the misaligned flag set to indicate that
540 * the alignment_offset is undefined.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400541 */
542int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500543 sector_t start)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400544{
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500545 unsigned int top, bottom, alignment, ret = 0;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100546
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400547 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
548 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400549 t->max_write_same_sectors = min(t->max_write_same_sectors,
550 b->max_write_same_sectors);
Martin K. Petersen77634f32009-06-09 06:23:22 +0200551 t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400552
553 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
554 b->seg_boundary_mask);
555
Martin K. Petersen8a783622010-02-26 00:20:39 -0500556 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
Martin K. Petersen13f05c82010-09-10 20:50:10 +0200557 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
558 b->max_integrity_segments);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400559
560 t->max_segment_size = min_not_zero(t->max_segment_size,
561 b->max_segment_size);
562
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500563 t->misaligned |= b->misaligned;
564
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500565 alignment = queue_limit_alignment_offset(b, start);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100566
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100567 /* Bottom device has different alignment. Check that it is
568 * compatible with the current top alignment.
569 */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100570 if (t->alignment_offset != alignment) {
571
572 top = max(t->physical_block_size, t->io_min)
573 + t->alignment_offset;
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100574 bottom = max(b->physical_block_size, b->io_min) + alignment;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100575
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100576 /* Verify that top and bottom intervals line up */
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500577 if (max(top, bottom) & (min(top, bottom) - 1)) {
Martin K. Petersen9504e082009-12-21 15:55:51 +0100578 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500579 ret = -1;
580 }
Martin K. Petersen9504e082009-12-21 15:55:51 +0100581 }
582
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400583 t->logical_block_size = max(t->logical_block_size,
584 b->logical_block_size);
585
586 t->physical_block_size = max(t->physical_block_size,
587 b->physical_block_size);
588
589 t->io_min = max(t->io_min, b->io_min);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100590 t->io_opt = lcm(t->io_opt, b->io_opt);
591
Martin K. Petersene692cb62010-12-01 19:41:49 +0100592 t->cluster &= b->cluster;
Martin K. Petersen98262f22009-12-03 09:24:48 +0100593 t->discard_zeroes_data &= b->discard_zeroes_data;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400594
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100595 /* Physical block size a multiple of the logical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100596 if (t->physical_block_size & (t->logical_block_size - 1)) {
597 t->physical_block_size = t->logical_block_size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400598 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500599 ret = -1;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100600 }
601
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100602 /* Minimum I/O a multiple of the physical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100603 if (t->io_min & (t->physical_block_size - 1)) {
604 t->io_min = t->physical_block_size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400605 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500606 ret = -1;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400607 }
608
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100609 /* Optimal I/O a multiple of the physical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100610 if (t->io_opt & (t->physical_block_size - 1)) {
611 t->io_opt = 0;
612 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500613 ret = -1;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100614 }
Martin K. Petersen70dd5bf2009-07-31 11:49:12 -0400615
Kent Overstreetc78afc62013-07-11 22:39:53 -0700616 t->raid_partial_stripes_expensive =
617 max(t->raid_partial_stripes_expensive,
618 b->raid_partial_stripes_expensive);
619
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100620 /* Find lowest common alignment_offset */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100621 t->alignment_offset = lcm(t->alignment_offset, alignment)
622 & (max(t->physical_block_size, t->io_min) - 1);
Martin K. Petersen70dd5bf2009-07-31 11:49:12 -0400623
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100624 /* Verify that new alignment_offset is on a logical block boundary */
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500625 if (t->alignment_offset & (t->logical_block_size - 1)) {
Martin K. Petersen9504e082009-12-21 15:55:51 +0100626 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500627 ret = -1;
628 }
Martin K. Petersen9504e082009-12-21 15:55:51 +0100629
630 /* Discard alignment and granularity */
631 if (b->discard_granularity) {
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500632 alignment = queue_limit_discard_alignment(b, start);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100633
634 if (t->discard_granularity != 0 &&
635 t->discard_alignment != alignment) {
636 top = t->discard_granularity + t->discard_alignment;
637 bottom = b->discard_granularity + alignment;
638
639 /* Verify that top and bottom intervals line up */
Shaohua Li8dd2cb72012-12-14 11:15:36 +0800640 if ((max(top, bottom) % min(top, bottom)) != 0)
Martin K. Petersen9504e082009-12-21 15:55:51 +0100641 t->discard_misaligned = 1;
642 }
643
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100644 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
645 b->max_discard_sectors);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100646 t->discard_granularity = max(t->discard_granularity,
647 b->discard_granularity);
Shaohua Li8dd2cb72012-12-14 11:15:36 +0800648 t->discard_alignment = lcm(t->discard_alignment, alignment) %
649 t->discard_granularity;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100650 }
651
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500652 return ret;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400653}
Mike Snitzer5d85d322009-05-28 11:04:53 +0200654EXPORT_SYMBOL(blk_stack_limits);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400655
656/**
Martin K. Petersen17be8c22010-01-11 03:21:49 -0500657 * bdev_stack_limits - adjust queue limits for stacked drivers
658 * @t: the stacking driver limits (top device)
659 * @bdev: the component block_device (bottom)
660 * @start: first data sector within component device
661 *
662 * Description:
663 * Merges queue limits for a top device and a block_device. Returns
664 * 0 if alignment didn't change. Returns -1 if adding the bottom
665 * device caused misalignment.
666 */
667int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
668 sector_t start)
669{
670 struct request_queue *bq = bdev_get_queue(bdev);
671
672 start += get_start_sect(bdev);
673
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500674 return blk_stack_limits(t, &bq->limits, start);
Martin K. Petersen17be8c22010-01-11 03:21:49 -0500675}
676EXPORT_SYMBOL(bdev_stack_limits);
677
678/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400679 * disk_stack_limits - adjust queue limits for stacked drivers
Martin K. Petersen77634f32009-06-09 06:23:22 +0200680 * @disk: MD/DM gendisk (top)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400681 * @bdev: the underlying block device (bottom)
682 * @offset: offset to beginning of data within component device
683 *
684 * Description:
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500685 * Merges the limits for a top level gendisk and a bottom level
686 * block_device.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400687 */
688void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
689 sector_t offset)
690{
691 struct request_queue *t = disk->queue;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400692
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500693 if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400694 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
695
696 disk_name(disk, 0, top);
697 bdevname(bdev, bottom);
698
699 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
700 top, bottom);
701 }
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400702}
703EXPORT_SYMBOL(disk_stack_limits);
704
705/**
Tejun Heoe3790c72008-03-04 11:18:17 +0100706 * blk_queue_dma_pad - set pad mask
707 * @q: the request queue for the device
708 * @mask: pad mask
709 *
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200710 * Set dma pad mask.
Tejun Heoe3790c72008-03-04 11:18:17 +0100711 *
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200712 * Appending pad buffer to a request modifies the last entry of a
713 * scatter list such that it includes the pad buffer.
Tejun Heoe3790c72008-03-04 11:18:17 +0100714 **/
715void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
716{
717 q->dma_pad_mask = mask;
718}
719EXPORT_SYMBOL(blk_queue_dma_pad);
720
721/**
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200722 * blk_queue_update_dma_pad - update pad mask
723 * @q: the request queue for the device
724 * @mask: pad mask
725 *
726 * Update dma pad mask.
727 *
728 * Appending pad buffer to a request modifies the last entry of a
729 * scatter list such that it includes the pad buffer.
730 **/
731void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
732{
733 if (mask > q->dma_pad_mask)
734 q->dma_pad_mask = mask;
735}
736EXPORT_SYMBOL(blk_queue_update_dma_pad);
737
738/**
Jens Axboe86db1e22008-01-29 14:53:40 +0100739 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
Jens Axboe86db1e22008-01-29 14:53:40 +0100740 * @q: the request queue for the device
Tejun Heo2fb98e82008-02-19 11:36:53 +0100741 * @dma_drain_needed: fn which returns non-zero if drain is necessary
Jens Axboe86db1e22008-01-29 14:53:40 +0100742 * @buf: physically contiguous buffer
743 * @size: size of the buffer in bytes
744 *
745 * Some devices have excess DMA problems and can't simply discard (or
746 * zero fill) the unwanted piece of the transfer. They have to have a
747 * real area of memory to transfer it into. The use case for this is
748 * ATAPI devices in DMA mode. If the packet command causes a transfer
749 * bigger than the transfer size some HBAs will lock up if there
750 * aren't DMA elements to contain the excess transfer. What this API
751 * does is adjust the queue so that the buf is always appended
752 * silently to the scatterlist.
753 *
Martin K. Petersen8a783622010-02-26 00:20:39 -0500754 * Note: This routine adjusts max_hw_segments to make room for appending
755 * the drain buffer. If you call blk_queue_max_segments() after calling
756 * this routine, you must set the limit to one fewer than your device
757 * can support otherwise there won't be room for the drain buffer.
Jens Axboe86db1e22008-01-29 14:53:40 +0100758 */
Harvey Harrison448da4d2008-03-04 11:30:18 +0100759int blk_queue_dma_drain(struct request_queue *q,
Tejun Heo2fb98e82008-02-19 11:36:53 +0100760 dma_drain_needed_fn *dma_drain_needed,
761 void *buf, unsigned int size)
Jens Axboe86db1e22008-01-29 14:53:40 +0100762{
Martin K. Petersen8a783622010-02-26 00:20:39 -0500763 if (queue_max_segments(q) < 2)
Jens Axboe86db1e22008-01-29 14:53:40 +0100764 return -EINVAL;
765 /* make room for appending the drain */
Martin K. Petersen8a783622010-02-26 00:20:39 -0500766 blk_queue_max_segments(q, queue_max_segments(q) - 1);
Tejun Heo2fb98e82008-02-19 11:36:53 +0100767 q->dma_drain_needed = dma_drain_needed;
Jens Axboe86db1e22008-01-29 14:53:40 +0100768 q->dma_drain_buffer = buf;
769 q->dma_drain_size = size;
770
771 return 0;
772}
Jens Axboe86db1e22008-01-29 14:53:40 +0100773EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
774
775/**
776 * blk_queue_segment_boundary - set boundary rules for segment merging
777 * @q: the request queue for the device
778 * @mask: the memory boundary mask
779 **/
780void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
781{
782 if (mask < PAGE_CACHE_SIZE - 1) {
783 mask = PAGE_CACHE_SIZE - 1;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700784 printk(KERN_INFO "%s: set to minimum %lx\n",
785 __func__, mask);
Jens Axboe86db1e22008-01-29 14:53:40 +0100786 }
787
Martin K. Petersen025146e2009-05-22 17:17:51 -0400788 q->limits.seg_boundary_mask = mask;
Jens Axboe86db1e22008-01-29 14:53:40 +0100789}
Jens Axboe86db1e22008-01-29 14:53:40 +0100790EXPORT_SYMBOL(blk_queue_segment_boundary);
791
792/**
793 * blk_queue_dma_alignment - set dma length and memory alignment
794 * @q: the request queue for the device
795 * @mask: alignment mask
796 *
797 * description:
Randy Dunlap710027a2008-08-19 20:13:11 +0200798 * set required memory and length alignment for direct dma transactions.
Alan Cox8feb4d22009-04-01 15:01:39 +0100799 * this is used when building direct io requests for the queue.
Jens Axboe86db1e22008-01-29 14:53:40 +0100800 *
801 **/
802void blk_queue_dma_alignment(struct request_queue *q, int mask)
803{
804 q->dma_alignment = mask;
805}
Jens Axboe86db1e22008-01-29 14:53:40 +0100806EXPORT_SYMBOL(blk_queue_dma_alignment);
807
808/**
809 * blk_queue_update_dma_alignment - update dma length and memory alignment
810 * @q: the request queue for the device
811 * @mask: alignment mask
812 *
813 * description:
Randy Dunlap710027a2008-08-19 20:13:11 +0200814 * update required memory and length alignment for direct dma transactions.
Jens Axboe86db1e22008-01-29 14:53:40 +0100815 * If the requested alignment is larger than the current alignment, then
816 * the current queue alignment is updated to the new value, otherwise it
817 * is left alone. The design of this is to allow multiple objects
818 * (driver, device, transport etc) to set their respective
819 * alignments without having them interfere.
820 *
821 **/
822void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
823{
824 BUG_ON(mask > PAGE_SIZE);
825
826 if (mask > q->dma_alignment)
827 q->dma_alignment = mask;
828}
Jens Axboe86db1e22008-01-29 14:53:40 +0100829EXPORT_SYMBOL(blk_queue_update_dma_alignment);
830
Tejun Heo4913efe2010-09-03 11:56:16 +0200831/**
832 * blk_queue_flush - configure queue's cache flush capability
833 * @q: the request queue for the device
834 * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
835 *
836 * Tell block layer cache flush capability of @q. If it supports
837 * flushing, REQ_FLUSH should be set. If it supports bypassing
838 * write cache for individual writes, REQ_FUA should be set.
839 */
840void blk_queue_flush(struct request_queue *q, unsigned int flush)
841{
842 WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
843
844 if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
845 flush &= ~REQ_FUA;
846
847 q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
848}
849EXPORT_SYMBOL_GPL(blk_queue_flush);
850
shaohua.li@intel.comf3876932011-05-06 11:34:32 -0600851void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
852{
853 q->flush_not_queueable = !queueable;
854}
855EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
856
Harvey Harrisonaeb3d3a2008-08-28 09:27:42 +0200857static int __init blk_settings_init(void)
Jens Axboe86db1e22008-01-29 14:53:40 +0100858{
859 blk_max_low_pfn = max_low_pfn - 1;
860 blk_max_pfn = max_pfn - 1;
861 return 0;
862}
863subsys_initcall(blk_settings_init);