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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - drivers/md/dm-io.c
2 * Copyright (C) 2003 Sistina Software
3 * Copyright (C) 2006 Red Hat GmbH
5 * This file is released under the GPL.
10 #include <linux/bio.h>
11 #include <linux/mempool.h>
12 #include <linux/module.h>
13 #include <linux/sched.h>
14 #include <linux/slab.h>
21 /* FIXME: can we shrink this ? */
25 struct task_struct
*sleeper
;
26 struct dm_io_client
*client
;
27 io_notify_fn callback
;
32 * io contexts are only dynamically allocated for asynchronous
33 * io. Since async io is likely to be the majority of io we'll
34 * have the same number of io contexts as bios! (FIXME: must reduce this).
37 static unsigned int pages_to_ios(unsigned int pages
)
39 return 4 * pages
; /* too many ? */
43 * Create a client with mempool and bioset.
45 struct dm_io_client
*dm_io_client_create(unsigned num_pages
)
47 unsigned ios
= pages_to_ios(num_pages
);
48 struct dm_io_client
*client
;
50 client
= kmalloc(sizeof(*client
), GFP_KERNEL
);
52 return ERR_PTR(-ENOMEM
);
54 client
->pool
= mempool_create_kmalloc_pool(ios
, sizeof(struct io
));
58 client
->bios
= bioset_create(16, 16);
66 mempool_destroy(client
->pool
);
68 return ERR_PTR(-ENOMEM
);
70 EXPORT_SYMBOL(dm_io_client_create
);
72 int dm_io_client_resize(unsigned num_pages
, struct dm_io_client
*client
)
74 return mempool_resize(client
->pool
, pages_to_ios(num_pages
),
77 EXPORT_SYMBOL(dm_io_client_resize
);
79 void dm_io_client_destroy(struct dm_io_client
*client
)
81 mempool_destroy(client
->pool
);
82 bioset_free(client
->bios
);
85 EXPORT_SYMBOL(dm_io_client_destroy
);
87 /*-----------------------------------------------------------------
88 * We need to keep track of which region a bio is doing io for.
89 * In order to save a memory allocation we store this the last
90 * bvec which we know is unused (blech).
91 * XXX This is ugly and can OOPS with some configs... find another way.
92 *---------------------------------------------------------------*/
93 static inline void bio_set_region(struct bio
*bio
, unsigned region
)
95 bio
->bi_io_vec
[bio
->bi_max_vecs
].bv_len
= region
;
98 static inline unsigned bio_get_region(struct bio
*bio
)
100 return bio
->bi_io_vec
[bio
->bi_max_vecs
].bv_len
;
103 /*-----------------------------------------------------------------
104 * We need an io object to keep track of the number of bios that
105 * have been dispatched for a particular io.
106 *---------------------------------------------------------------*/
107 static void dec_count(struct io
*io
, unsigned int region
, int error
)
110 set_bit(region
, &io
->error
);
112 if (atomic_dec_and_test(&io
->count
)) {
114 wake_up_process(io
->sleeper
);
117 unsigned long r
= io
->error
;
118 io_notify_fn fn
= io
->callback
;
119 void *context
= io
->context
;
121 mempool_free(io
, io
->client
->pool
);
127 static void endio(struct bio
*bio
, int error
)
132 if (error
&& bio_data_dir(bio
) == READ
)
136 * The bio destructor in bio_put() may use the io object.
138 io
= bio
->bi_private
;
139 region
= bio_get_region(bio
);
144 dec_count(io
, region
, error
);
147 /*-----------------------------------------------------------------
148 * These little objects provide an abstraction for getting a new
149 * destination page for io.
150 *---------------------------------------------------------------*/
152 void (*get_page
)(struct dpages
*dp
,
153 struct page
**p
, unsigned long *len
, unsigned *offset
);
154 void (*next_page
)(struct dpages
*dp
);
161 * Functions for getting the pages from a list.
163 static void list_get_page(struct dpages
*dp
,
164 struct page
**p
, unsigned long *len
, unsigned *offset
)
166 unsigned o
= dp
->context_u
;
167 struct page_list
*pl
= (struct page_list
*) dp
->context_ptr
;
170 *len
= PAGE_SIZE
- o
;
174 static void list_next_page(struct dpages
*dp
)
176 struct page_list
*pl
= (struct page_list
*) dp
->context_ptr
;
177 dp
->context_ptr
= pl
->next
;
181 static void list_dp_init(struct dpages
*dp
, struct page_list
*pl
, unsigned offset
)
183 dp
->get_page
= list_get_page
;
184 dp
->next_page
= list_next_page
;
185 dp
->context_u
= offset
;
186 dp
->context_ptr
= pl
;
190 * Functions for getting the pages from a bvec.
192 static void bvec_get_page(struct dpages
*dp
,
193 struct page
**p
, unsigned long *len
, unsigned *offset
)
195 struct bio_vec
*bvec
= (struct bio_vec
*) dp
->context_ptr
;
198 *offset
= bvec
->bv_offset
;
201 static void bvec_next_page(struct dpages
*dp
)
203 struct bio_vec
*bvec
= (struct bio_vec
*) dp
->context_ptr
;
204 dp
->context_ptr
= bvec
+ 1;
207 static void bvec_dp_init(struct dpages
*dp
, struct bio_vec
*bvec
)
209 dp
->get_page
= bvec_get_page
;
210 dp
->next_page
= bvec_next_page
;
211 dp
->context_ptr
= bvec
;
215 * Functions for getting the pages from a VMA.
217 static void vm_get_page(struct dpages
*dp
,
218 struct page
**p
, unsigned long *len
, unsigned *offset
)
220 *p
= vmalloc_to_page(dp
->context_ptr
);
221 *offset
= dp
->context_u
;
222 *len
= PAGE_SIZE
- dp
->context_u
;
225 static void vm_next_page(struct dpages
*dp
)
227 dp
->context_ptr
+= PAGE_SIZE
- dp
->context_u
;
231 static void vm_dp_init(struct dpages
*dp
, void *data
)
233 dp
->get_page
= vm_get_page
;
234 dp
->next_page
= vm_next_page
;
235 dp
->context_u
= ((unsigned long) data
) & (PAGE_SIZE
- 1);
236 dp
->context_ptr
= data
;
239 static void dm_bio_destructor(struct bio
*bio
)
241 struct io
*io
= bio
->bi_private
;
243 bio_free(bio
, io
->client
->bios
);
247 * Functions for getting the pages from kernel memory.
249 static void km_get_page(struct dpages
*dp
, struct page
**p
, unsigned long *len
,
252 *p
= virt_to_page(dp
->context_ptr
);
253 *offset
= dp
->context_u
;
254 *len
= PAGE_SIZE
- dp
->context_u
;
257 static void km_next_page(struct dpages
*dp
)
259 dp
->context_ptr
+= PAGE_SIZE
- dp
->context_u
;
263 static void km_dp_init(struct dpages
*dp
, void *data
)
265 dp
->get_page
= km_get_page
;
266 dp
->next_page
= km_next_page
;
267 dp
->context_u
= ((unsigned long) data
) & (PAGE_SIZE
- 1);
268 dp
->context_ptr
= data
;
271 /*-----------------------------------------------------------------
272 * IO routines that accept a list of pages.
273 *---------------------------------------------------------------*/
274 static void do_region(int rw
, unsigned int region
, struct io_region
*where
,
275 struct dpages
*dp
, struct io
*io
)
282 sector_t remaining
= where
->count
;
286 * Allocate a suitably sized-bio: we add an extra
287 * bvec for bio_get/set_region() and decrement bi_max_vecs
288 * to hide it from bio_add_page().
290 num_bvecs
= dm_sector_div_up(remaining
,
291 (PAGE_SIZE
>> SECTOR_SHIFT
));
292 num_bvecs
= 1 + min_t(int, bio_get_nr_vecs(where
->bdev
),
294 bio
= bio_alloc_bioset(GFP_NOIO
, num_bvecs
, io
->client
->bios
);
295 bio
->bi_sector
= where
->sector
+ (where
->count
- remaining
);
296 bio
->bi_bdev
= where
->bdev
;
297 bio
->bi_end_io
= endio
;
298 bio
->bi_private
= io
;
299 bio
->bi_destructor
= dm_bio_destructor
;
301 bio_set_region(bio
, region
);
304 * Try and add as many pages as possible.
307 dp
->get_page(dp
, &page
, &len
, &offset
);
308 len
= min(len
, to_bytes(remaining
));
309 if (!bio_add_page(bio
, page
, len
, offset
))
313 remaining
-= to_sector(len
);
317 atomic_inc(&io
->count
);
322 static void dispatch_io(int rw
, unsigned int num_regions
,
323 struct io_region
*where
, struct dpages
*dp
,
324 struct io
*io
, int sync
)
327 struct dpages old_pages
= *dp
;
330 rw
|= (1 << BIO_RW_SYNC
);
333 * For multiple regions we need to be careful to rewind
334 * the dp object for each call to do_region.
336 for (i
= 0; i
< num_regions
; i
++) {
339 do_region(rw
, i
, where
+ i
, dp
, io
);
343 * Drop the extra reference that we were holding to avoid
344 * the io being completed too early.
349 static int sync_io(struct dm_io_client
*client
, unsigned int num_regions
,
350 struct io_region
*where
, int rw
, struct dpages
*dp
,
351 unsigned long *error_bits
)
355 if (num_regions
> 1 && rw
!= WRITE
) {
361 atomic_set(&io
.count
, 1); /* see dispatch_io() */
362 io
.sleeper
= current
;
365 dispatch_io(rw
, num_regions
, where
, dp
, &io
, 1);
368 set_current_state(TASK_UNINTERRUPTIBLE
);
370 if (!atomic_read(&io
.count
) || signal_pending(current
))
375 set_current_state(TASK_RUNNING
);
377 if (atomic_read(&io
.count
))
381 *error_bits
= io
.error
;
383 return io
.error
? -EIO
: 0;
386 static int async_io(struct dm_io_client
*client
, unsigned int num_regions
,
387 struct io_region
*where
, int rw
, struct dpages
*dp
,
388 io_notify_fn fn
, void *context
)
392 if (num_regions
> 1 && rw
!= WRITE
) {
398 io
= mempool_alloc(client
->pool
, GFP_NOIO
);
400 atomic_set(&io
->count
, 1); /* see dispatch_io() */
404 io
->context
= context
;
406 dispatch_io(rw
, num_regions
, where
, dp
, io
, 0);
410 static int dp_init(struct dm_io_request
*io_req
, struct dpages
*dp
)
412 /* Set up dpages based on memory type */
413 switch (io_req
->mem
.type
) {
414 case DM_IO_PAGE_LIST
:
415 list_dp_init(dp
, io_req
->mem
.ptr
.pl
, io_req
->mem
.offset
);
419 bvec_dp_init(dp
, io_req
->mem
.ptr
.bvec
);
423 vm_dp_init(dp
, io_req
->mem
.ptr
.vma
);
427 km_dp_init(dp
, io_req
->mem
.ptr
.addr
);
438 * New collapsed (a)synchronous interface
440 int dm_io(struct dm_io_request
*io_req
, unsigned num_regions
,
441 struct io_region
*where
, unsigned long *sync_error_bits
)
446 r
= dp_init(io_req
, &dp
);
450 if (!io_req
->notify
.fn
)
451 return sync_io(io_req
->client
, num_regions
, where
,
452 io_req
->bi_rw
, &dp
, sync_error_bits
);
454 return async_io(io_req
->client
, num_regions
, where
, io_req
->bi_rw
,
455 &dp
, io_req
->notify
.fn
, io_req
->notify
.context
);
457 EXPORT_SYMBOL(dm_io
);