2 * Copyright (C) 2003 Sistina Software
3 * Copyright (C) 2006 Red Hat GmbH
5 * This file is released under the GPL.
10 #include <linux/device-mapper.h>
12 #include <linux/bio.h>
13 #include <linux/completion.h>
14 #include <linux/mempool.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/slab.h>
18 #include <linux/dm-io.h>
20 #define DM_MSG_PREFIX "io"
22 #define DM_IO_MAX_REGIONS BITS_PER_LONG
30 * Aligning 'struct io' reduces the number of bits required to store
31 * its address. Refer to store_io_and_region_in_bio() below.
34 unsigned long error_bits
;
36 struct dm_io_client
*client
;
37 io_notify_fn callback
;
39 void *vma_invalidate_address
;
40 unsigned long vma_invalidate_size
;
41 } __attribute__((aligned(DM_IO_MAX_REGIONS
)));
43 static struct kmem_cache
*_dm_io_cache
;
46 * Create a client with mempool and bioset.
48 struct dm_io_client
*dm_io_client_create(void)
50 struct dm_io_client
*client
;
51 unsigned min_ios
= dm_get_reserved_bio_based_ios();
53 client
= kmalloc(sizeof(*client
), GFP_KERNEL
);
55 return ERR_PTR(-ENOMEM
);
57 client
->pool
= mempool_create_slab_pool(min_ios
, _dm_io_cache
);
61 client
->bios
= bioset_create(min_ios
, 0);
68 mempool_destroy(client
->pool
);
70 return ERR_PTR(-ENOMEM
);
72 EXPORT_SYMBOL(dm_io_client_create
);
74 void dm_io_client_destroy(struct dm_io_client
*client
)
76 mempool_destroy(client
->pool
);
77 bioset_free(client
->bios
);
80 EXPORT_SYMBOL(dm_io_client_destroy
);
82 /*-----------------------------------------------------------------
83 * We need to keep track of which region a bio is doing io for.
84 * To avoid a memory allocation to store just 5 or 6 bits, we
85 * ensure the 'struct io' pointer is aligned so enough low bits are
86 * always zero and then combine it with the region number directly in
88 *---------------------------------------------------------------*/
89 static void store_io_and_region_in_bio(struct bio
*bio
, struct io
*io
,
92 if (unlikely(!IS_ALIGNED((unsigned long)io
, DM_IO_MAX_REGIONS
))) {
93 DMCRIT("Unaligned struct io pointer %p", io
);
97 bio
->bi_private
= (void *)((unsigned long)io
| region
);
100 static void retrieve_io_and_region_from_bio(struct bio
*bio
, struct io
**io
,
103 unsigned long val
= (unsigned long)bio
->bi_private
;
105 *io
= (void *)(val
& -(unsigned long)DM_IO_MAX_REGIONS
);
106 *region
= val
& (DM_IO_MAX_REGIONS
- 1);
109 /*-----------------------------------------------------------------
110 * We need an io object to keep track of the number of bios that
111 * have been dispatched for a particular io.
112 *---------------------------------------------------------------*/
113 static void complete_io(struct io
*io
)
115 unsigned long error_bits
= io
->error_bits
;
116 io_notify_fn fn
= io
->callback
;
117 void *context
= io
->context
;
119 if (io
->vma_invalidate_size
)
120 invalidate_kernel_vmap_range(io
->vma_invalidate_address
,
121 io
->vma_invalidate_size
);
123 mempool_free(io
, io
->client
->pool
);
124 fn(error_bits
, context
);
127 static void dec_count(struct io
*io
, unsigned int region
, int error
)
130 set_bit(region
, &io
->error_bits
);
132 if (atomic_dec_and_test(&io
->count
))
136 static void endio(struct bio
*bio
)
142 if (bio
->bi_error
&& bio_data_dir(bio
) == READ
)
146 * The bio destructor in bio_put() may use the io object.
148 retrieve_io_and_region_from_bio(bio
, &io
, ®ion
);
150 error
= bio
->bi_error
;
153 dec_count(io
, region
, error
);
156 /*-----------------------------------------------------------------
157 * These little objects provide an abstraction for getting a new
158 * destination page for io.
159 *---------------------------------------------------------------*/
161 void (*get_page
)(struct dpages
*dp
,
162 struct page
**p
, unsigned long *len
, unsigned *offset
);
163 void (*next_page
)(struct dpages
*dp
);
168 void *vma_invalidate_address
;
169 unsigned long vma_invalidate_size
;
173 * Functions for getting the pages from a list.
175 static void list_get_page(struct dpages
*dp
,
176 struct page
**p
, unsigned long *len
, unsigned *offset
)
178 unsigned o
= dp
->context_u
;
179 struct page_list
*pl
= (struct page_list
*) dp
->context_ptr
;
182 *len
= PAGE_SIZE
- o
;
186 static void list_next_page(struct dpages
*dp
)
188 struct page_list
*pl
= (struct page_list
*) dp
->context_ptr
;
189 dp
->context_ptr
= pl
->next
;
193 static void list_dp_init(struct dpages
*dp
, struct page_list
*pl
, unsigned offset
)
195 dp
->get_page
= list_get_page
;
196 dp
->next_page
= list_next_page
;
197 dp
->context_u
= offset
;
198 dp
->context_ptr
= pl
;
202 * Functions for getting the pages from a bvec.
204 static void bio_get_page(struct dpages
*dp
, struct page
**p
,
205 unsigned long *len
, unsigned *offset
)
207 struct bio_vec
*bvec
= dp
->context_ptr
;
209 *len
= bvec
->bv_len
- dp
->context_u
;
210 *offset
= bvec
->bv_offset
+ dp
->context_u
;
213 static void bio_next_page(struct dpages
*dp
)
215 struct bio_vec
*bvec
= dp
->context_ptr
;
216 dp
->context_ptr
= bvec
+ 1;
220 static void bio_dp_init(struct dpages
*dp
, struct bio
*bio
)
222 dp
->get_page
= bio_get_page
;
223 dp
->next_page
= bio_next_page
;
224 dp
->context_ptr
= __bvec_iter_bvec(bio
->bi_io_vec
, bio
->bi_iter
);
225 dp
->context_u
= bio
->bi_iter
.bi_bvec_done
;
229 * Functions for getting the pages from a VMA.
231 static void vm_get_page(struct dpages
*dp
,
232 struct page
**p
, unsigned long *len
, unsigned *offset
)
234 *p
= vmalloc_to_page(dp
->context_ptr
);
235 *offset
= dp
->context_u
;
236 *len
= PAGE_SIZE
- dp
->context_u
;
239 static void vm_next_page(struct dpages
*dp
)
241 dp
->context_ptr
+= PAGE_SIZE
- dp
->context_u
;
245 static void vm_dp_init(struct dpages
*dp
, void *data
)
247 dp
->get_page
= vm_get_page
;
248 dp
->next_page
= vm_next_page
;
249 dp
->context_u
= offset_in_page(data
);
250 dp
->context_ptr
= data
;
254 * Functions for getting the pages from kernel memory.
256 static void km_get_page(struct dpages
*dp
, struct page
**p
, unsigned long *len
,
259 *p
= virt_to_page(dp
->context_ptr
);
260 *offset
= dp
->context_u
;
261 *len
= PAGE_SIZE
- dp
->context_u
;
264 static void km_next_page(struct dpages
*dp
)
266 dp
->context_ptr
+= PAGE_SIZE
- dp
->context_u
;
270 static void km_dp_init(struct dpages
*dp
, void *data
)
272 dp
->get_page
= km_get_page
;
273 dp
->next_page
= km_next_page
;
274 dp
->context_u
= offset_in_page(data
);
275 dp
->context_ptr
= data
;
278 /*-----------------------------------------------------------------
279 * IO routines that accept a list of pages.
280 *---------------------------------------------------------------*/
281 static void do_region(int rw
, unsigned region
, struct dm_io_region
*where
,
282 struct dpages
*dp
, struct io
*io
)
289 sector_t remaining
= where
->count
;
290 struct request_queue
*q
= bdev_get_queue(where
->bdev
);
291 unsigned short logical_block_size
= queue_logical_block_size(q
);
292 sector_t num_sectors
;
293 unsigned int uninitialized_var(special_cmd_max_sectors
);
296 * Reject unsupported discard and write same requests.
298 if (rw
& REQ_DISCARD
)
299 special_cmd_max_sectors
= q
->limits
.max_discard_sectors
;
300 else if (rw
& REQ_WRITE_SAME
)
301 special_cmd_max_sectors
= q
->limits
.max_write_same_sectors
;
302 if ((rw
& (REQ_DISCARD
| REQ_WRITE_SAME
)) && special_cmd_max_sectors
== 0) {
303 dec_count(io
, region
, -EOPNOTSUPP
);
308 * where->count may be zero if rw holds a flush and we need to
309 * send a zero-sized flush.
313 * Allocate a suitably sized-bio.
315 if ((rw
& REQ_DISCARD
) || (rw
& REQ_WRITE_SAME
))
318 num_bvecs
= min_t(int, BIO_MAX_PAGES
,
319 dm_sector_div_up(remaining
, (PAGE_SIZE
>> SECTOR_SHIFT
)));
321 bio
= bio_alloc_bioset(GFP_NOIO
, num_bvecs
, io
->client
->bios
);
322 bio
->bi_iter
.bi_sector
= where
->sector
+ (where
->count
- remaining
);
323 bio
->bi_bdev
= where
->bdev
;
324 bio
->bi_end_io
= endio
;
325 store_io_and_region_in_bio(bio
, io
, region
);
327 if (rw
& REQ_DISCARD
) {
328 num_sectors
= min_t(sector_t
, special_cmd_max_sectors
, remaining
);
329 bio
->bi_iter
.bi_size
= num_sectors
<< SECTOR_SHIFT
;
330 remaining
-= num_sectors
;
331 } else if (rw
& REQ_WRITE_SAME
) {
333 * WRITE SAME only uses a single page.
335 dp
->get_page(dp
, &page
, &len
, &offset
);
336 bio_add_page(bio
, page
, logical_block_size
, offset
);
337 num_sectors
= min_t(sector_t
, special_cmd_max_sectors
, remaining
);
338 bio
->bi_iter
.bi_size
= num_sectors
<< SECTOR_SHIFT
;
341 remaining
-= num_sectors
;
343 } else while (remaining
) {
345 * Try and add as many pages as possible.
347 dp
->get_page(dp
, &page
, &len
, &offset
);
348 len
= min(len
, to_bytes(remaining
));
349 if (!bio_add_page(bio
, page
, len
, offset
))
353 remaining
-= to_sector(len
);
357 atomic_inc(&io
->count
);
362 static void dispatch_io(int rw
, unsigned int num_regions
,
363 struct dm_io_region
*where
, struct dpages
*dp
,
364 struct io
*io
, int sync
)
367 struct dpages old_pages
= *dp
;
369 BUG_ON(num_regions
> DM_IO_MAX_REGIONS
);
375 * For multiple regions we need to be careful to rewind
376 * the dp object for each call to do_region.
378 for (i
= 0; i
< num_regions
; i
++) {
380 if (where
[i
].count
|| (rw
& REQ_FLUSH
))
381 do_region(rw
, i
, where
+ i
, dp
, io
);
385 * Drop the extra reference that we were holding to avoid
386 * the io being completed too early.
392 unsigned long error_bits
;
393 struct completion wait
;
396 static void sync_io_complete(unsigned long error
, void *context
)
398 struct sync_io
*sio
= context
;
400 sio
->error_bits
= error
;
401 complete(&sio
->wait
);
404 static int sync_io(struct dm_io_client
*client
, unsigned int num_regions
,
405 struct dm_io_region
*where
, int rw
, struct dpages
*dp
,
406 unsigned long *error_bits
)
411 if (num_regions
> 1 && (rw
& RW_MASK
) != WRITE
) {
416 init_completion(&sio
.wait
);
418 io
= mempool_alloc(client
->pool
, GFP_NOIO
);
420 atomic_set(&io
->count
, 1); /* see dispatch_io() */
422 io
->callback
= sync_io_complete
;
425 io
->vma_invalidate_address
= dp
->vma_invalidate_address
;
426 io
->vma_invalidate_size
= dp
->vma_invalidate_size
;
428 dispatch_io(rw
, num_regions
, where
, dp
, io
, 1);
430 wait_for_completion_io(&sio
.wait
);
433 *error_bits
= sio
.error_bits
;
435 return sio
.error_bits
? -EIO
: 0;
438 static int async_io(struct dm_io_client
*client
, unsigned int num_regions
,
439 struct dm_io_region
*where
, int rw
, struct dpages
*dp
,
440 io_notify_fn fn
, void *context
)
444 if (num_regions
> 1 && (rw
& RW_MASK
) != WRITE
) {
450 io
= mempool_alloc(client
->pool
, GFP_NOIO
);
452 atomic_set(&io
->count
, 1); /* see dispatch_io() */
455 io
->context
= context
;
457 io
->vma_invalidate_address
= dp
->vma_invalidate_address
;
458 io
->vma_invalidate_size
= dp
->vma_invalidate_size
;
460 dispatch_io(rw
, num_regions
, where
, dp
, io
, 0);
464 static int dp_init(struct dm_io_request
*io_req
, struct dpages
*dp
,
467 /* Set up dpages based on memory type */
469 dp
->vma_invalidate_address
= NULL
;
470 dp
->vma_invalidate_size
= 0;
472 switch (io_req
->mem
.type
) {
473 case DM_IO_PAGE_LIST
:
474 list_dp_init(dp
, io_req
->mem
.ptr
.pl
, io_req
->mem
.offset
);
478 bio_dp_init(dp
, io_req
->mem
.ptr
.bio
);
482 flush_kernel_vmap_range(io_req
->mem
.ptr
.vma
, size
);
483 if ((io_req
->bi_rw
& RW_MASK
) == READ
) {
484 dp
->vma_invalidate_address
= io_req
->mem
.ptr
.vma
;
485 dp
->vma_invalidate_size
= size
;
487 vm_dp_init(dp
, io_req
->mem
.ptr
.vma
);
491 km_dp_init(dp
, io_req
->mem
.ptr
.addr
);
502 * New collapsed (a)synchronous interface.
504 * If the IO is asynchronous (i.e. it has notify.fn), you must either unplug
505 * the queue with blk_unplug() some time later or set REQ_SYNC in io_req->bi_rw.
506 * If you fail to do one of these, the IO will be submitted to the disk after
507 * q->unplug_delay, which defaults to 3ms in blk-settings.c.
509 int dm_io(struct dm_io_request
*io_req
, unsigned num_regions
,
510 struct dm_io_region
*where
, unsigned long *sync_error_bits
)
515 r
= dp_init(io_req
, &dp
, (unsigned long)where
->count
<< SECTOR_SHIFT
);
519 if (!io_req
->notify
.fn
)
520 return sync_io(io_req
->client
, num_regions
, where
,
521 io_req
->bi_rw
, &dp
, sync_error_bits
);
523 return async_io(io_req
->client
, num_regions
, where
, io_req
->bi_rw
,
524 &dp
, io_req
->notify
.fn
, io_req
->notify
.context
);
526 EXPORT_SYMBOL(dm_io
);
528 int __init
dm_io_init(void)
530 _dm_io_cache
= KMEM_CACHE(io
, 0);
537 void dm_io_exit(void)
539 kmem_cache_destroy(_dm_io_cache
);
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