blob: dd49735839789167d427dc8b64da71c6b21f08f5 [file] [log] [blame]
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
Jens Axboe86db1e22008-01-29 14:53:40 +010056void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
57{
58 q->softirq_done_fn = fn;
59}
Jens Axboe86db1e22008-01-29 14:53:40 +010060EXPORT_SYMBOL(blk_queue_softirq_done);
61
Jens Axboe242f9dc2008-09-14 05:55:09 -070062void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
63{
64 q->rq_timeout = timeout;
65}
66EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
67
68void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
69{
70 q->rq_timed_out_fn = fn;
71}
72EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
73
Kiyoshi Uedaef9e3fa2008-10-01 16:12:15 +020074void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
75{
76 q->lld_busy_fn = fn;
77}
78EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
79
Jens Axboe86db1e22008-01-29 14:53:40 +010080/**
Martin K. Petersene475bba2009-06-16 08:23:52 +020081 * blk_set_default_limits - reset limits to default values
Randy Dunlapf740f5ca2009-06-19 09:18:32 +020082 * @lim: the queue_limits structure to reset
Martin K. Petersene475bba2009-06-16 08:23:52 +020083 *
84 * Description:
Martin K. Petersenb1bd0552012-01-11 16:27:11 +010085 * Returns a queue_limit struct to its default state.
Martin K. Petersene475bba2009-06-16 08:23:52 +020086 */
87void blk_set_default_limits(struct queue_limits *lim)
88{
Martin K. Petersen8a783622010-02-26 00:20:39 -050089 lim->max_segments = BLK_MAX_SEGMENTS;
Martin K. Petersen13f05c82010-09-10 20:50:10 +020090 lim->max_integrity_segments = 0;
Martin K. Petersene475bba2009-06-16 08:23:52 +020091 lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
Keith Busch03100aa2015-08-19 14:24:05 -070092 lim->virt_boundary_mask = 0;
Martin K. Peterseneb28d312010-02-26 00:20:37 -050093 lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
Martin K. Petersenca369d52015-11-13 16:46:48 -050094 lim->max_sectors = lim->max_dev_sectors = lim->max_hw_sectors =
95 BLK_SAFE_MAX_SECTORS;
Jens Axboe762380a2014-06-05 13:38:39 -060096 lim->chunk_sectors = 0;
Martin K. Petersen4363ac72012-09-18 12:19:27 -040097 lim->max_write_same_sectors = 0;
Martin K. Petersen86b37282009-11-10 11:50:21 +010098 lim->max_discard_sectors = 0;
Jens Axboe0034af02015-07-16 09:14:26 -060099 lim->max_hw_discard_sectors = 0;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100100 lim->discard_granularity = 0;
101 lim->discard_alignment = 0;
102 lim->discard_misaligned = 0;
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100103 lim->discard_zeroes_data = 0;
Martin K. Petersene475bba2009-06-16 08:23:52 +0200104 lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
Martin K. Petersen3a02c8e2009-06-18 09:56:03 +0200105 lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
Martin K. Petersene475bba2009-06-16 08:23:52 +0200106 lim->alignment_offset = 0;
107 lim->io_opt = 0;
108 lim->misaligned = 0;
Martin K. Petersene692cb62010-12-01 19:41:49 +0100109 lim->cluster = 1;
Martin K. Petersene475bba2009-06-16 08:23:52 +0200110}
111EXPORT_SYMBOL(blk_set_default_limits);
112
113/**
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100114 * blk_set_stacking_limits - set default limits for stacking devices
115 * @lim: the queue_limits structure to reset
116 *
117 * Description:
118 * Returns a queue_limit struct to its default state. Should be used
119 * by stacking drivers like DM that have no internal limits.
120 */
121void blk_set_stacking_limits(struct queue_limits *lim)
122{
123 blk_set_default_limits(lim);
124
125 /* Inherit limits from component devices */
126 lim->discard_zeroes_data = 1;
127 lim->max_segments = USHRT_MAX;
128 lim->max_hw_sectors = UINT_MAX;
Mike Snitzerd82ae522013-10-18 09:44:49 -0600129 lim->max_segment_size = UINT_MAX;
Mike Snitzerfe86cdc2012-08-01 10:44:28 +0200130 lim->max_sectors = UINT_MAX;
Martin K. Petersenca369d52015-11-13 16:46:48 -0500131 lim->max_dev_sectors = UINT_MAX;
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400132 lim->max_write_same_sectors = UINT_MAX;
Martin K. Petersenb1bd0552012-01-11 16:27:11 +0100133}
134EXPORT_SYMBOL(blk_set_stacking_limits);
135
136/**
Jens Axboe86db1e22008-01-29 14:53:40 +0100137 * blk_queue_make_request - define an alternate make_request function for a device
138 * @q: the request queue for the device to be affected
139 * @mfn: the alternate make_request function
140 *
141 * Description:
142 * The normal way for &struct bios to be passed to a device
143 * driver is for them to be collected into requests on a request
144 * queue, and then to allow the device driver to select requests
145 * off that queue when it is ready. This works well for many block
146 * devices. However some block devices (typically virtual devices
147 * such as md or lvm) do not benefit from the processing on the
148 * request queue, and are served best by having the requests passed
149 * directly to them. This can be achieved by providing a function
150 * to blk_queue_make_request().
151 *
152 * Caveat:
153 * The driver that does this *must* be able to deal appropriately
154 * with buffers in "highmemory". This can be accomplished by either calling
155 * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
156 * blk_queue_bounce() to create a buffer in normal memory.
157 **/
Jens Axboe6728cb02008-01-31 13:03:55 +0100158void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
Jens Axboe86db1e22008-01-29 14:53:40 +0100159{
160 /*
161 * set defaults
162 */
163 q->nr_requests = BLKDEV_MAX_RQ;
Milan Broz0e435ac2008-12-03 12:55:08 +0100164
Jens Axboe86db1e22008-01-29 14:53:40 +0100165 q->make_request_fn = mfn;
Jens Axboe86db1e22008-01-29 14:53:40 +0100166 blk_queue_dma_alignment(q, 511);
167 blk_queue_congestion_threshold(q);
168 q->nr_batching = BLK_BATCH_REQ;
169
Martin K. Petersene475bba2009-06-16 08:23:52 +0200170 blk_set_default_limits(&q->limits);
171
Jens Axboe86db1e22008-01-29 14:53:40 +0100172 /*
173 * by default assume old behaviour and bounce for any highmem page
174 */
175 blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
176}
Jens Axboe86db1e22008-01-29 14:53:40 +0100177EXPORT_SYMBOL(blk_queue_make_request);
178
179/**
180 * blk_queue_bounce_limit - set bounce buffer limit for queue
Tejun Heocd0aca22009-04-15 22:10:25 +0900181 * @q: the request queue for the device
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100182 * @max_addr: the maximum address the device can handle
Jens Axboe86db1e22008-01-29 14:53:40 +0100183 *
184 * Description:
185 * Different hardware can have different requirements as to what pages
186 * it can do I/O directly to. A low level driver can call
187 * blk_queue_bounce_limit to have lower memory pages allocated as bounce
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100188 * buffers for doing I/O to pages residing above @max_addr.
Jens Axboe86db1e22008-01-29 14:53:40 +0100189 **/
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100190void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr)
Jens Axboe86db1e22008-01-29 14:53:40 +0100191{
Santosh Shilimkar9f7e45d2013-07-29 14:17:54 +0100192 unsigned long b_pfn = max_addr >> PAGE_SHIFT;
Jens Axboe86db1e22008-01-29 14:53:40 +0100193 int dma = 0;
194
195 q->bounce_gfp = GFP_NOIO;
196#if BITS_PER_LONG == 64
Tejun Heocd0aca22009-04-15 22:10:25 +0900197 /*
198 * Assume anything <= 4GB can be handled by IOMMU. Actually
199 * some IOMMUs can handle everything, but I don't know of a
200 * way to test this here.
201 */
202 if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
Jens Axboe86db1e22008-01-29 14:53:40 +0100203 dma = 1;
Malahal Naineniefb012b2010-10-01 14:45:27 +0200204 q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
Jens Axboe86db1e22008-01-29 14:53:40 +0100205#else
Jens Axboe6728cb02008-01-31 13:03:55 +0100206 if (b_pfn < blk_max_low_pfn)
Jens Axboe86db1e22008-01-29 14:53:40 +0100207 dma = 1;
Malahal Nainenic49825f2010-09-24 20:25:49 +0200208 q->limits.bounce_pfn = b_pfn;
Jens Axboe260a67a2010-10-01 14:42:43 +0200209#endif
Jens Axboe86db1e22008-01-29 14:53:40 +0100210 if (dma) {
211 init_emergency_isa_pool();
212 q->bounce_gfp = GFP_NOIO | GFP_DMA;
Jens Axboe260a67a2010-10-01 14:42:43 +0200213 q->limits.bounce_pfn = b_pfn;
Jens Axboe86db1e22008-01-29 14:53:40 +0100214 }
215}
Jens Axboe86db1e22008-01-29 14:53:40 +0100216EXPORT_SYMBOL(blk_queue_bounce_limit);
217
218/**
Martin K. Petersenca369d52015-11-13 16:46:48 -0500219 * blk_queue_max_hw_sectors - set max sectors for a request for this queue
220 * @q: the request queue for the device
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500221 * @max_hw_sectors: max hardware sectors in the usual 512b unit
Jens Axboe86db1e22008-01-29 14:53:40 +0100222 *
223 * Description:
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500224 * Enables a low level driver to set a hard upper limit,
225 * max_hw_sectors, on the size of requests. max_hw_sectors is set by
Martin K. Petersen4f258a42015-06-23 12:13:59 -0400226 * the device driver based upon the capabilities of the I/O
227 * controller.
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500228 *
Martin K. Petersenca369d52015-11-13 16:46:48 -0500229 * max_dev_sectors is a hard limit imposed by the storage device for
230 * READ/WRITE requests. It is set by the disk driver.
231 *
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500232 * max_sectors is a soft limit imposed by the block layer for
233 * filesystem type requests. This value can be overridden on a
234 * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
235 * The soft limit can not exceed max_hw_sectors.
Jens Axboe86db1e22008-01-29 14:53:40 +0100236 **/
Martin K. Petersenca369d52015-11-13 16:46:48 -0500237void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
Jens Axboe86db1e22008-01-29 14:53:40 +0100238{
Martin K. Petersenca369d52015-11-13 16:46:48 -0500239 struct queue_limits *limits = &q->limits;
240 unsigned int max_sectors;
241
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500242 if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
243 max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
Harvey Harrison24c03d42008-05-01 04:35:17 -0700244 printk(KERN_INFO "%s: set to minimum %d\n",
Martin K. Petersen2800aac2010-02-26 00:20:35 -0500245 __func__, max_hw_sectors);
Jens Axboe86db1e22008-01-29 14:53:40 +0100246 }
247
Jeff Moyer30e2bc02015-08-13 14:57:56 -0400248 limits->max_hw_sectors = max_hw_sectors;
Martin K. Petersenca369d52015-11-13 16:46:48 -0500249 max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors);
250 max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS);
251 limits->max_sectors = max_sectors;
Jens Axboe86db1e22008-01-29 14:53:40 +0100252}
Martin K. Petersen086fa5f2010-02-26 00:20:38 -0500253EXPORT_SYMBOL(blk_queue_max_hw_sectors);
Jens Axboe86db1e22008-01-29 14:53:40 +0100254
255/**
Jens Axboe762380a2014-06-05 13:38:39 -0600256 * blk_queue_chunk_sectors - set size of the chunk for this queue
257 * @q: the request queue for the device
258 * @chunk_sectors: chunk sectors in the usual 512b unit
259 *
260 * Description:
261 * If a driver doesn't want IOs to cross a given chunk size, it can set
262 * this limit and prevent merging across chunks. Note that the chunk size
Jens Axboe58a49152014-06-10 12:53:56 -0600263 * must currently be a power-of-2 in sectors. Also note that the block
264 * layer must accept a page worth of data at any offset. So if the
265 * crossing of chunks is a hard limitation in the driver, it must still be
266 * prepared to split single page bios.
Jens Axboe762380a2014-06-05 13:38:39 -0600267 **/
268void blk_queue_chunk_sectors(struct request_queue *q, unsigned int chunk_sectors)
269{
270 BUG_ON(!is_power_of_2(chunk_sectors));
271 q->limits.chunk_sectors = chunk_sectors;
272}
273EXPORT_SYMBOL(blk_queue_chunk_sectors);
274
275/**
Christoph Hellwig67efc922009-09-30 13:54:20 +0200276 * blk_queue_max_discard_sectors - set max sectors for a single discard
277 * @q: the request queue for the device
Randy Dunlapc7ebf062009-10-12 08:20:47 +0200278 * @max_discard_sectors: maximum number of sectors to discard
Christoph Hellwig67efc922009-09-30 13:54:20 +0200279 **/
280void blk_queue_max_discard_sectors(struct request_queue *q,
281 unsigned int max_discard_sectors)
282{
Jens Axboe0034af02015-07-16 09:14:26 -0600283 q->limits.max_hw_discard_sectors = max_discard_sectors;
Christoph Hellwig67efc922009-09-30 13:54:20 +0200284 q->limits.max_discard_sectors = max_discard_sectors;
285}
286EXPORT_SYMBOL(blk_queue_max_discard_sectors);
287
288/**
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400289 * blk_queue_max_write_same_sectors - set max sectors for a single write same
290 * @q: the request queue for the device
291 * @max_write_same_sectors: maximum number of sectors to write per command
292 **/
293void blk_queue_max_write_same_sectors(struct request_queue *q,
294 unsigned int max_write_same_sectors)
295{
296 q->limits.max_write_same_sectors = max_write_same_sectors;
297}
298EXPORT_SYMBOL(blk_queue_max_write_same_sectors);
299
300/**
Martin K. Petersen8a783622010-02-26 00:20:39 -0500301 * blk_queue_max_segments - set max hw segments for a request for this queue
Jens Axboe86db1e22008-01-29 14:53:40 +0100302 * @q: the request queue for the device
303 * @max_segments: max number of segments
304 *
305 * Description:
306 * Enables a low level driver to set an upper limit on the number of
Martin K. Petersen8a783622010-02-26 00:20:39 -0500307 * hw data segments in a request.
Jens Axboe86db1e22008-01-29 14:53:40 +0100308 **/
Martin K. Petersen8a783622010-02-26 00:20:39 -0500309void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
Jens Axboe86db1e22008-01-29 14:53:40 +0100310{
311 if (!max_segments) {
312 max_segments = 1;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700313 printk(KERN_INFO "%s: set to minimum %d\n",
314 __func__, max_segments);
Jens Axboe86db1e22008-01-29 14:53:40 +0100315 }
316
Martin K. Petersen8a783622010-02-26 00:20:39 -0500317 q->limits.max_segments = max_segments;
Jens Axboe86db1e22008-01-29 14:53:40 +0100318}
Martin K. Petersen8a783622010-02-26 00:20:39 -0500319EXPORT_SYMBOL(blk_queue_max_segments);
Jens Axboe86db1e22008-01-29 14:53:40 +0100320
321/**
322 * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
323 * @q: the request queue for the device
324 * @max_size: max size of segment in bytes
325 *
326 * Description:
327 * Enables a low level driver to set an upper limit on the size of a
328 * coalesced segment
329 **/
330void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
331{
332 if (max_size < PAGE_CACHE_SIZE) {
333 max_size = PAGE_CACHE_SIZE;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700334 printk(KERN_INFO "%s: set to minimum %d\n",
335 __func__, max_size);
Jens Axboe86db1e22008-01-29 14:53:40 +0100336 }
337
Martin K. Petersen025146e2009-05-22 17:17:51 -0400338 q->limits.max_segment_size = max_size;
Jens Axboe86db1e22008-01-29 14:53:40 +0100339}
Jens Axboe86db1e22008-01-29 14:53:40 +0100340EXPORT_SYMBOL(blk_queue_max_segment_size);
341
342/**
Martin K. Petersene1defc42009-05-22 17:17:49 -0400343 * blk_queue_logical_block_size - set logical block size for the queue
Jens Axboe86db1e22008-01-29 14:53:40 +0100344 * @q: the request queue for the device
Martin K. Petersene1defc42009-05-22 17:17:49 -0400345 * @size: the logical block size, in bytes
Jens Axboe86db1e22008-01-29 14:53:40 +0100346 *
347 * Description:
Martin K. Petersene1defc42009-05-22 17:17:49 -0400348 * This should be set to the lowest possible block size that the
349 * storage device can address. The default of 512 covers most
350 * hardware.
Jens Axboe86db1e22008-01-29 14:53:40 +0100351 **/
Martin K. Petersene1defc42009-05-22 17:17:49 -0400352void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
Jens Axboe86db1e22008-01-29 14:53:40 +0100353{
Martin K. Petersen025146e2009-05-22 17:17:51 -0400354 q->limits.logical_block_size = size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400355
356 if (q->limits.physical_block_size < size)
357 q->limits.physical_block_size = size;
358
359 if (q->limits.io_min < q->limits.physical_block_size)
360 q->limits.io_min = q->limits.physical_block_size;
Jens Axboe86db1e22008-01-29 14:53:40 +0100361}
Martin K. Petersene1defc42009-05-22 17:17:49 -0400362EXPORT_SYMBOL(blk_queue_logical_block_size);
Jens Axboe86db1e22008-01-29 14:53:40 +0100363
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400364/**
365 * blk_queue_physical_block_size - set physical block size for the queue
366 * @q: the request queue for the device
367 * @size: the physical block size, in bytes
368 *
369 * Description:
370 * This should be set to the lowest possible sector size that the
371 * hardware can operate on without reverting to read-modify-write
372 * operations.
373 */
Martin K. Petersen892b6f92010-10-13 21:18:03 +0200374void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400375{
376 q->limits.physical_block_size = size;
377
378 if (q->limits.physical_block_size < q->limits.logical_block_size)
379 q->limits.physical_block_size = q->limits.logical_block_size;
380
381 if (q->limits.io_min < q->limits.physical_block_size)
382 q->limits.io_min = q->limits.physical_block_size;
383}
384EXPORT_SYMBOL(blk_queue_physical_block_size);
385
386/**
387 * blk_queue_alignment_offset - set physical block alignment offset
388 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700389 * @offset: alignment offset in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400390 *
391 * Description:
392 * Some devices are naturally misaligned to compensate for things like
393 * the legacy DOS partition table 63-sector offset. Low-level drivers
394 * should call this function for devices whose first sector is not
395 * naturally aligned.
396 */
397void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
398{
399 q->limits.alignment_offset =
400 offset & (q->limits.physical_block_size - 1);
401 q->limits.misaligned = 0;
402}
403EXPORT_SYMBOL(blk_queue_alignment_offset);
404
405/**
Martin K. Petersen7c958e32009-07-31 11:49:11 -0400406 * blk_limits_io_min - set minimum request size for a device
407 * @limits: the queue limits
408 * @min: smallest I/O size in bytes
409 *
410 * Description:
411 * Some devices have an internal block size bigger than the reported
412 * hardware sector size. This function can be used to signal the
413 * smallest I/O the device can perform without incurring a performance
414 * penalty.
415 */
416void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
417{
418 limits->io_min = min;
419
420 if (limits->io_min < limits->logical_block_size)
421 limits->io_min = limits->logical_block_size;
422
423 if (limits->io_min < limits->physical_block_size)
424 limits->io_min = limits->physical_block_size;
425}
426EXPORT_SYMBOL(blk_limits_io_min);
427
428/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400429 * blk_queue_io_min - set minimum request size for the queue
430 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700431 * @min: smallest I/O size in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400432 *
433 * Description:
Martin K. Petersen7e5f5fb2009-07-31 11:49:13 -0400434 * Storage devices may report a granularity or preferred minimum I/O
435 * size which is the smallest request the device can perform without
436 * incurring a performance penalty. For disk drives this is often the
437 * physical block size. For RAID arrays it is often the stripe chunk
438 * size. A properly aligned multiple of minimum_io_size is the
439 * preferred request size for workloads where a high number of I/O
440 * operations is desired.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400441 */
442void blk_queue_io_min(struct request_queue *q, unsigned int min)
443{
Martin K. Petersen7c958e32009-07-31 11:49:11 -0400444 blk_limits_io_min(&q->limits, min);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400445}
446EXPORT_SYMBOL(blk_queue_io_min);
447
448/**
Martin K. Petersen3c5820c2009-09-11 21:54:52 +0200449 * blk_limits_io_opt - set optimal request size for a device
450 * @limits: the queue limits
451 * @opt: smallest I/O size in bytes
452 *
453 * Description:
454 * Storage devices may report an optimal I/O size, which is the
455 * device's preferred unit for sustained I/O. This is rarely reported
456 * for disk drives. For RAID arrays it is usually the stripe width or
457 * the internal track size. A properly aligned multiple of
458 * optimal_io_size is the preferred request size for workloads where
459 * sustained throughput is desired.
460 */
461void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
462{
463 limits->io_opt = opt;
464}
465EXPORT_SYMBOL(blk_limits_io_opt);
466
467/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400468 * blk_queue_io_opt - set optimal request size for the queue
469 * @q: the request queue for the device
Randy Dunlap8ebf9752009-06-11 20:00:41 -0700470 * @opt: optimal request size in bytes
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400471 *
472 * Description:
Martin K. Petersen7e5f5fb2009-07-31 11:49:13 -0400473 * Storage devices may report an optimal I/O size, which is the
474 * device's preferred unit for sustained I/O. This is rarely reported
475 * for disk drives. For RAID arrays it is usually the stripe width or
476 * the internal track size. A properly aligned multiple of
477 * optimal_io_size is the preferred request size for workloads where
478 * sustained throughput is desired.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400479 */
480void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
481{
Martin K. Petersen3c5820c2009-09-11 21:54:52 +0200482 blk_limits_io_opt(&q->limits, opt);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400483}
484EXPORT_SYMBOL(blk_queue_io_opt);
485
Jens Axboe86db1e22008-01-29 14:53:40 +0100486/**
487 * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
488 * @t: the stacking driver (top)
489 * @b: the underlying device (bottom)
490 **/
491void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
492{
Martin K. Petersenfef24662009-07-31 11:49:10 -0400493 blk_stack_limits(&t->limits, &b->limits, 0);
Jens Axboe86db1e22008-01-29 14:53:40 +0100494}
Jens Axboe86db1e22008-01-29 14:53:40 +0100495EXPORT_SYMBOL(blk_queue_stack_limits);
496
497/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400498 * blk_stack_limits - adjust queue_limits for stacked devices
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100499 * @t: the stacking driver limits (top device)
500 * @b: the underlying queue limits (bottom, component device)
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500501 * @start: first data sector within component device
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400502 *
503 * Description:
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100504 * This function is used by stacking drivers like MD and DM to ensure
505 * that all component devices have compatible block sizes and
506 * alignments. The stacking driver must provide a queue_limits
507 * struct (top) and then iteratively call the stacking function for
508 * all component (bottom) devices. The stacking function will
509 * attempt to combine the values and ensure proper alignment.
510 *
511 * Returns 0 if the top and bottom queue_limits are compatible. The
512 * top device's block sizes and alignment offsets may be adjusted to
513 * ensure alignment with the bottom device. If no compatible sizes
514 * and alignments exist, -1 is returned and the resulting top
515 * queue_limits will have the misaligned flag set to indicate that
516 * the alignment_offset is undefined.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400517 */
518int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500519 sector_t start)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400520{
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500521 unsigned int top, bottom, alignment, ret = 0;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100522
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400523 t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
524 t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
Martin K. Petersenca369d52015-11-13 16:46:48 -0500525 t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors);
Martin K. Petersen4363ac72012-09-18 12:19:27 -0400526 t->max_write_same_sectors = min(t->max_write_same_sectors,
527 b->max_write_same_sectors);
Martin K. Petersen77634f32009-06-09 06:23:22 +0200528 t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400529
530 t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
531 b->seg_boundary_mask);
Keith Busch03100aa2015-08-19 14:24:05 -0700532 t->virt_boundary_mask = min_not_zero(t->virt_boundary_mask,
533 b->virt_boundary_mask);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400534
Martin K. Petersen8a783622010-02-26 00:20:39 -0500535 t->max_segments = min_not_zero(t->max_segments, b->max_segments);
Martin K. Petersen13f05c82010-09-10 20:50:10 +0200536 t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
537 b->max_integrity_segments);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400538
539 t->max_segment_size = min_not_zero(t->max_segment_size,
540 b->max_segment_size);
541
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500542 t->misaligned |= b->misaligned;
543
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500544 alignment = queue_limit_alignment_offset(b, start);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100545
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100546 /* Bottom device has different alignment. Check that it is
547 * compatible with the current top alignment.
548 */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100549 if (t->alignment_offset != alignment) {
550
551 top = max(t->physical_block_size, t->io_min)
552 + t->alignment_offset;
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100553 bottom = max(b->physical_block_size, b->io_min) + alignment;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100554
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100555 /* Verify that top and bottom intervals line up */
Mike Snitzerb8839b82014-10-08 18:26:13 -0400556 if (max(top, bottom) % min(top, bottom)) {
Martin K. Petersen9504e082009-12-21 15:55:51 +0100557 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500558 ret = -1;
559 }
Martin K. Petersen9504e082009-12-21 15:55:51 +0100560 }
561
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400562 t->logical_block_size = max(t->logical_block_size,
563 b->logical_block_size);
564
565 t->physical_block_size = max(t->physical_block_size,
566 b->physical_block_size);
567
568 t->io_min = max(t->io_min, b->io_min);
Mike Snitzere9637412015-03-30 13:39:09 -0400569 t->io_opt = lcm_not_zero(t->io_opt, b->io_opt);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100570
Martin K. Petersene692cb62010-12-01 19:41:49 +0100571 t->cluster &= b->cluster;
Martin K. Petersen98262f22009-12-03 09:24:48 +0100572 t->discard_zeroes_data &= b->discard_zeroes_data;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400573
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100574 /* Physical block size a multiple of the logical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100575 if (t->physical_block_size & (t->logical_block_size - 1)) {
576 t->physical_block_size = t->logical_block_size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400577 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500578 ret = -1;
Martin K. Petersen86b37282009-11-10 11:50:21 +0100579 }
580
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100581 /* Minimum I/O a multiple of the physical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100582 if (t->io_min & (t->physical_block_size - 1)) {
583 t->io_min = t->physical_block_size;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400584 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500585 ret = -1;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400586 }
587
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100588 /* Optimal I/O a multiple of the physical block size? */
Martin K. Petersen9504e082009-12-21 15:55:51 +0100589 if (t->io_opt & (t->physical_block_size - 1)) {
590 t->io_opt = 0;
591 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500592 ret = -1;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100593 }
Martin K. Petersen70dd5bf2009-07-31 11:49:12 -0400594
Kent Overstreetc78afc62013-07-11 22:39:53 -0700595 t->raid_partial_stripes_expensive =
596 max(t->raid_partial_stripes_expensive,
597 b->raid_partial_stripes_expensive);
598
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100599 /* Find lowest common alignment_offset */
Mike Snitzere9637412015-03-30 13:39:09 -0400600 t->alignment_offset = lcm_not_zero(t->alignment_offset, alignment)
Mike Snitzerb8839b82014-10-08 18:26:13 -0400601 % max(t->physical_block_size, t->io_min);
Martin K. Petersen70dd5bf2009-07-31 11:49:12 -0400602
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100603 /* Verify that new alignment_offset is on a logical block boundary */
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500604 if (t->alignment_offset & (t->logical_block_size - 1)) {
Martin K. Petersen9504e082009-12-21 15:55:51 +0100605 t->misaligned = 1;
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500606 ret = -1;
607 }
Martin K. Petersen9504e082009-12-21 15:55:51 +0100608
609 /* Discard alignment and granularity */
610 if (b->discard_granularity) {
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500611 alignment = queue_limit_discard_alignment(b, start);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100612
613 if (t->discard_granularity != 0 &&
614 t->discard_alignment != alignment) {
615 top = t->discard_granularity + t->discard_alignment;
616 bottom = b->discard_granularity + alignment;
617
618 /* Verify that top and bottom intervals line up */
Shaohua Li8dd2cb72012-12-14 11:15:36 +0800619 if ((max(top, bottom) % min(top, bottom)) != 0)
Martin K. Petersen9504e082009-12-21 15:55:51 +0100620 t->discard_misaligned = 1;
621 }
622
Martin K. Petersen81744ee2009-12-29 08:35:35 +0100623 t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
624 b->max_discard_sectors);
Jens Axboe0034af02015-07-16 09:14:26 -0600625 t->max_hw_discard_sectors = min_not_zero(t->max_hw_discard_sectors,
626 b->max_hw_discard_sectors);
Martin K. Petersen9504e082009-12-21 15:55:51 +0100627 t->discard_granularity = max(t->discard_granularity,
628 b->discard_granularity);
Mike Snitzere9637412015-03-30 13:39:09 -0400629 t->discard_alignment = lcm_not_zero(t->discard_alignment, alignment) %
Shaohua Li8dd2cb72012-12-14 11:15:36 +0800630 t->discard_granularity;
Martin K. Petersen9504e082009-12-21 15:55:51 +0100631 }
632
Martin K. Petersenfe0b3932010-01-11 03:21:47 -0500633 return ret;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400634}
Mike Snitzer5d85d322009-05-28 11:04:53 +0200635EXPORT_SYMBOL(blk_stack_limits);
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400636
637/**
Martin K. Petersen17be8c22010-01-11 03:21:49 -0500638 * bdev_stack_limits - adjust queue limits for stacked drivers
639 * @t: the stacking driver limits (top device)
640 * @bdev: the component block_device (bottom)
641 * @start: first data sector within component device
642 *
643 * Description:
644 * Merges queue limits for a top device and a block_device. Returns
645 * 0 if alignment didn't change. Returns -1 if adding the bottom
646 * device caused misalignment.
647 */
648int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
649 sector_t start)
650{
651 struct request_queue *bq = bdev_get_queue(bdev);
652
653 start += get_start_sect(bdev);
654
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500655 return blk_stack_limits(t, &bq->limits, start);
Martin K. Petersen17be8c22010-01-11 03:21:49 -0500656}
657EXPORT_SYMBOL(bdev_stack_limits);
658
659/**
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400660 * disk_stack_limits - adjust queue limits for stacked drivers
Martin K. Petersen77634f32009-06-09 06:23:22 +0200661 * @disk: MD/DM gendisk (top)
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400662 * @bdev: the underlying block device (bottom)
663 * @offset: offset to beginning of data within component device
664 *
665 * Description:
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500666 * Merges the limits for a top level gendisk and a bottom level
667 * block_device.
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400668 */
669void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
670 sector_t offset)
671{
672 struct request_queue *t = disk->queue;
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400673
Martin K. Petersene03a72e2010-01-11 03:21:51 -0500674 if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400675 char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
676
677 disk_name(disk, 0, top);
678 bdevname(bdev, bottom);
679
680 printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
681 top, bottom);
682 }
Martin K. Petersenc72758f2009-05-22 17:17:53 -0400683}
684EXPORT_SYMBOL(disk_stack_limits);
685
686/**
Tejun Heoe3790c72008-03-04 11:18:17 +0100687 * blk_queue_dma_pad - set pad mask
688 * @q: the request queue for the device
689 * @mask: pad mask
690 *
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200691 * Set dma pad mask.
Tejun Heoe3790c72008-03-04 11:18:17 +0100692 *
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200693 * Appending pad buffer to a request modifies the last entry of a
694 * scatter list such that it includes the pad buffer.
Tejun Heoe3790c72008-03-04 11:18:17 +0100695 **/
696void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
697{
698 q->dma_pad_mask = mask;
699}
700EXPORT_SYMBOL(blk_queue_dma_pad);
701
702/**
FUJITA Tomonori27f82212008-07-04 09:30:03 +0200703 * blk_queue_update_dma_pad - update pad mask
704 * @q: the request queue for the device
705 * @mask: pad mask
706 *
707 * Update dma pad mask.
708 *
709 * Appending pad buffer to a request modifies the last entry of a
710 * scatter list such that it includes the pad buffer.
711 **/
712void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
713{
714 if (mask > q->dma_pad_mask)
715 q->dma_pad_mask = mask;
716}
717EXPORT_SYMBOL(blk_queue_update_dma_pad);
718
719/**
Jens Axboe86db1e22008-01-29 14:53:40 +0100720 * blk_queue_dma_drain - Set up a drain buffer for excess dma.
Jens Axboe86db1e22008-01-29 14:53:40 +0100721 * @q: the request queue for the device
Tejun Heo2fb98e82008-02-19 11:36:53 +0100722 * @dma_drain_needed: fn which returns non-zero if drain is necessary
Jens Axboe86db1e22008-01-29 14:53:40 +0100723 * @buf: physically contiguous buffer
724 * @size: size of the buffer in bytes
725 *
726 * Some devices have excess DMA problems and can't simply discard (or
727 * zero fill) the unwanted piece of the transfer. They have to have a
728 * real area of memory to transfer it into. The use case for this is
729 * ATAPI devices in DMA mode. If the packet command causes a transfer
730 * bigger than the transfer size some HBAs will lock up if there
731 * aren't DMA elements to contain the excess transfer. What this API
732 * does is adjust the queue so that the buf is always appended
733 * silently to the scatterlist.
734 *
Martin K. Petersen8a783622010-02-26 00:20:39 -0500735 * Note: This routine adjusts max_hw_segments to make room for appending
736 * the drain buffer. If you call blk_queue_max_segments() after calling
737 * this routine, you must set the limit to one fewer than your device
738 * can support otherwise there won't be room for the drain buffer.
Jens Axboe86db1e22008-01-29 14:53:40 +0100739 */
Harvey Harrison448da4d2008-03-04 11:30:18 +0100740int blk_queue_dma_drain(struct request_queue *q,
Tejun Heo2fb98e82008-02-19 11:36:53 +0100741 dma_drain_needed_fn *dma_drain_needed,
742 void *buf, unsigned int size)
Jens Axboe86db1e22008-01-29 14:53:40 +0100743{
Martin K. Petersen8a783622010-02-26 00:20:39 -0500744 if (queue_max_segments(q) < 2)
Jens Axboe86db1e22008-01-29 14:53:40 +0100745 return -EINVAL;
746 /* make room for appending the drain */
Martin K. Petersen8a783622010-02-26 00:20:39 -0500747 blk_queue_max_segments(q, queue_max_segments(q) - 1);
Tejun Heo2fb98e82008-02-19 11:36:53 +0100748 q->dma_drain_needed = dma_drain_needed;
Jens Axboe86db1e22008-01-29 14:53:40 +0100749 q->dma_drain_buffer = buf;
750 q->dma_drain_size = size;
751
752 return 0;
753}
Jens Axboe86db1e22008-01-29 14:53:40 +0100754EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
755
756/**
757 * blk_queue_segment_boundary - set boundary rules for segment merging
758 * @q: the request queue for the device
759 * @mask: the memory boundary mask
760 **/
761void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
762{
763 if (mask < PAGE_CACHE_SIZE - 1) {
764 mask = PAGE_CACHE_SIZE - 1;
Harvey Harrison24c03d42008-05-01 04:35:17 -0700765 printk(KERN_INFO "%s: set to minimum %lx\n",
766 __func__, mask);
Jens Axboe86db1e22008-01-29 14:53:40 +0100767 }
768
Martin K. Petersen025146e2009-05-22 17:17:51 -0400769 q->limits.seg_boundary_mask = mask;
Jens Axboe86db1e22008-01-29 14:53:40 +0100770}
Jens Axboe86db1e22008-01-29 14:53:40 +0100771EXPORT_SYMBOL(blk_queue_segment_boundary);
772
773/**
Keith Busch03100aa2015-08-19 14:24:05 -0700774 * blk_queue_virt_boundary - set boundary rules for bio merging
775 * @q: the request queue for the device
776 * @mask: the memory boundary mask
777 **/
778void blk_queue_virt_boundary(struct request_queue *q, unsigned long mask)
779{
780 q->limits.virt_boundary_mask = mask;
781}
782EXPORT_SYMBOL(blk_queue_virt_boundary);
783
784/**
Jens Axboe86db1e22008-01-29 14:53:40 +0100785 * blk_queue_dma_alignment - set dma length and memory alignment
786 * @q: the request queue for the device
787 * @mask: alignment mask
788 *
789 * description:
Randy Dunlap710027a2008-08-19 20:13:11 +0200790 * set required memory and length alignment for direct dma transactions.
Alan Cox8feb4d22009-04-01 15:01:39 +0100791 * this is used when building direct io requests for the queue.
Jens Axboe86db1e22008-01-29 14:53:40 +0100792 *
793 **/
794void blk_queue_dma_alignment(struct request_queue *q, int mask)
795{
796 q->dma_alignment = mask;
797}
Jens Axboe86db1e22008-01-29 14:53:40 +0100798EXPORT_SYMBOL(blk_queue_dma_alignment);
799
800/**
801 * blk_queue_update_dma_alignment - update dma length and memory alignment
802 * @q: the request queue for the device
803 * @mask: alignment mask
804 *
805 * description:
Randy Dunlap710027a2008-08-19 20:13:11 +0200806 * update required memory and length alignment for direct dma transactions.
Jens Axboe86db1e22008-01-29 14:53:40 +0100807 * If the requested alignment is larger than the current alignment, then
808 * the current queue alignment is updated to the new value, otherwise it
809 * is left alone. The design of this is to allow multiple objects
810 * (driver, device, transport etc) to set their respective
811 * alignments without having them interfere.
812 *
813 **/
814void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
815{
816 BUG_ON(mask > PAGE_SIZE);
817
818 if (mask > q->dma_alignment)
819 q->dma_alignment = mask;
820}
Jens Axboe86db1e22008-01-29 14:53:40 +0100821EXPORT_SYMBOL(blk_queue_update_dma_alignment);
822
Tejun Heo4913efe2010-09-03 11:56:16 +0200823/**
824 * blk_queue_flush - configure queue's cache flush capability
825 * @q: the request queue for the device
826 * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
827 *
828 * Tell block layer cache flush capability of @q. If it supports
829 * flushing, REQ_FLUSH should be set. If it supports bypassing
830 * write cache for individual writes, REQ_FUA should be set.
831 */
832void blk_queue_flush(struct request_queue *q, unsigned int flush)
833{
834 WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
835
836 if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
837 flush &= ~REQ_FUA;
838
839 q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
840}
841EXPORT_SYMBOL_GPL(blk_queue_flush);
842
shaohua.li@intel.comf3876932011-05-06 11:34:32 -0600843void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
844{
845 q->flush_not_queueable = !queueable;
846}
847EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
848
Harvey Harrisonaeb3d3a2008-08-28 09:27:42 +0200849static int __init blk_settings_init(void)
Jens Axboe86db1e22008-01-29 14:53:40 +0100850{
851 blk_max_low_pfn = max_low_pfn - 1;
852 blk_max_pfn = max_pfn - 1;
853 return 0;
854}
855subsys_initcall(blk_settings_init);