Commit | Line | Data |
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4d05a28d | 1 | /****************************************************************************** |
4d05a28d KRW |
2 | * |
3 | * Back-end of the driver for virtual block devices. This portion of the | |
4 | * driver exports a 'unified' block-device interface that can be accessed | |
5 | * by any operating system that implements a compatible front end. A | |
6 | * reference front-end implementation can be found in: | |
a1397fa3 | 7 | * drivers/block/xen-blkfront.c |
4d05a28d KRW |
8 | * |
9 | * Copyright (c) 2003-2004, Keir Fraser & Steve Hand | |
10 | * Copyright (c) 2005, Christopher Clark | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or | |
13 | * modify it under the terms of the GNU General Public License version 2 | |
14 | * as published by the Free Software Foundation; or, when distributed | |
15 | * separately from the Linux kernel or incorporated into other | |
16 | * software packages, subject to the following license: | |
17 | * | |
18 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
19 | * of this source file (the "Software"), to deal in the Software without | |
20 | * restriction, including without limitation the rights to use, copy, modify, | |
21 | * merge, publish, distribute, sublicense, and/or sell copies of the Software, | |
22 | * and to permit persons to whom the Software is furnished to do so, subject to | |
23 | * the following conditions: | |
24 | * | |
25 | * The above copyright notice and this permission notice shall be included in | |
26 | * all copies or substantial portions of the Software. | |
27 | * | |
28 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
29 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
30 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
31 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
32 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
33 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
34 | * IN THE SOFTWARE. | |
35 | */ | |
36 | ||
37 | #include <linux/spinlock.h> | |
38 | #include <linux/kthread.h> | |
39 | #include <linux/list.h> | |
40 | #include <linux/delay.h> | |
88122933 | 41 | #include <linux/freezer.h> |
0a8704a5 | 42 | #include <linux/bitmap.h> |
afd91d07 | 43 | |
88122933 JF |
44 | #include <xen/events.h> |
45 | #include <xen/page.h> | |
e79affc3 | 46 | #include <xen/xen.h> |
88122933 JF |
47 | #include <asm/xen/hypervisor.h> |
48 | #include <asm/xen/hypercall.h> | |
087ffecd | 49 | #include <xen/balloon.h> |
4d05a28d KRW |
50 | #include "common.h" |
51 | ||
52 | /* | |
53 | * These are rather arbitrary. They are fairly large because adjacent requests | |
54 | * pulled from a communication ring are quite likely to end up being part of | |
55 | * the same scatter/gather request at the disc. | |
56 | * | |
8b6bf747 | 57 | * ** TRY INCREASING 'xen_blkif_reqs' IF WRITE SPEEDS SEEM TOO LOW ** |
4d05a28d KRW |
58 | * |
59 | * This will increase the chances of being able to write whole tracks. | |
60 | * 64 should be enough to keep us competitive with Linux. | |
61 | */ | |
8b6bf747 KRW |
62 | static int xen_blkif_reqs = 64; |
63 | module_param_named(reqs, xen_blkif_reqs, int, 0); | |
4d05a28d KRW |
64 | MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate"); |
65 | ||
c6cc142d RPM |
66 | /* |
67 | * Maximum number of unused free pages to keep in the internal buffer. | |
68 | * Setting this to a value too low will reduce memory used in each backend, | |
69 | * but can have a performance penalty. | |
70 | * | |
71 | * A sane value is xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST, but can | |
72 | * be set to a lower value that might degrade performance on some intensive | |
73 | * IO workloads. | |
74 | */ | |
75 | ||
76 | static int xen_blkif_max_buffer_pages = 704; | |
77 | module_param_named(max_buffer_pages, xen_blkif_max_buffer_pages, int, 0644); | |
78 | MODULE_PARM_DESC(max_buffer_pages, | |
79 | "Maximum number of free pages to keep in each block backend buffer"); | |
80 | ||
3f3aad5e RPM |
81 | /* |
82 | * Maximum number of grants to map persistently in blkback. For maximum | |
83 | * performance this should be the total numbers of grants that can be used | |
84 | * to fill the ring, but since this might become too high, specially with | |
85 | * the use of indirect descriptors, we set it to a value that provides good | |
86 | * performance without using too much memory. | |
87 | * | |
88 | * When the list of persistent grants is full we clean it up using a LRU | |
89 | * algorithm. | |
90 | */ | |
91 | ||
92 | static int xen_blkif_max_pgrants = 352; | |
93 | module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644); | |
94 | MODULE_PARM_DESC(max_persistent_grants, | |
95 | "Maximum number of grants to map persistently"); | |
96 | ||
97 | /* | |
98 | * The LRU mechanism to clean the lists of persistent grants needs to | |
99 | * be executed periodically. The time interval between consecutive executions | |
100 | * of the purge mechanism is set in ms. | |
101 | */ | |
102 | #define LRU_INTERVAL 100 | |
103 | ||
104 | /* | |
105 | * When the persistent grants list is full we will remove unused grants | |
106 | * from the list. The percent number of grants to be removed at each LRU | |
107 | * execution. | |
108 | */ | |
109 | #define LRU_PERCENT_CLEAN 5 | |
110 | ||
4d05a28d | 111 | /* Run-time switchable: /sys/module/blkback/parameters/ */ |
2e9977c2 | 112 | static unsigned int log_stats; |
4d05a28d | 113 | module_param(log_stats, int, 0644); |
4d05a28d KRW |
114 | |
115 | /* | |
116 | * Each outstanding request that we've passed to the lower device layers has a | |
117 | * 'pending_req' allocated to it. Each buffer_head that completes decrements | |
118 | * the pendcnt towards zero. When it hits zero, the specified domain has a | |
119 | * response queued for it, with the saved 'id' passed back. | |
120 | */ | |
2e9977c2 | 121 | struct pending_req { |
30fd1502 | 122 | struct xen_blkif *blkif; |
01f37f2d KRW |
123 | u64 id; |
124 | int nr_pages; | |
125 | atomic_t pendcnt; | |
126 | unsigned short operation; | |
127 | int status; | |
128 | struct list_head free_list; | |
c6cc142d | 129 | struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
3f3aad5e | 130 | struct persistent_gnt *persistent_gnts[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
bb6acb28 | 131 | grant_handle_t grant_handles[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
2e9977c2 | 132 | }; |
4d05a28d | 133 | |
4d05a28d KRW |
134 | #define BLKBACK_INVALID_HANDLE (~0) |
135 | ||
c6cc142d RPM |
136 | /* Number of free pages to remove on each call to free_xenballooned_pages */ |
137 | #define NUM_BATCH_FREE_PAGES 10 | |
138 | ||
e8e28871 | 139 | struct xen_blkbk { |
2e9977c2 | 140 | struct pending_req *pending_reqs; |
a1397fa3 | 141 | /* List of all 'pending_req' available */ |
e8e28871 | 142 | struct list_head pending_free; |
a1397fa3 | 143 | /* And its spinlock. */ |
e8e28871 KRW |
144 | spinlock_t pending_free_lock; |
145 | wait_queue_head_t pending_free_wq; | |
e8e28871 KRW |
146 | }; |
147 | ||
148 | static struct xen_blkbk *blkbk; | |
4d05a28d | 149 | |
a1397fa3 KRW |
150 | /* |
151 | * Little helpful macro to figure out the index and virtual address of the | |
152 | * pending_pages[..]. For each 'pending_req' we have have up to | |
153 | * BLKIF_MAX_SEGMENTS_PER_REQUEST (11) pages. The seg would be from 0 through | |
01f37f2d KRW |
154 | * 10 and would index in the pending_pages[..]. |
155 | */ | |
2e9977c2 | 156 | static inline int vaddr_pagenr(struct pending_req *req, int seg) |
4d05a28d | 157 | { |
2e9977c2 KRW |
158 | return (req - blkbk->pending_reqs) * |
159 | BLKIF_MAX_SEGMENTS_PER_REQUEST + seg; | |
4d05a28d KRW |
160 | } |
161 | ||
c6cc142d RPM |
162 | static inline int get_free_page(struct xen_blkif *blkif, struct page **page) |
163 | { | |
164 | unsigned long flags; | |
165 | ||
166 | spin_lock_irqsave(&blkif->free_pages_lock, flags); | |
167 | if (list_empty(&blkif->free_pages)) { | |
168 | BUG_ON(blkif->free_pages_num != 0); | |
169 | spin_unlock_irqrestore(&blkif->free_pages_lock, flags); | |
170 | return alloc_xenballooned_pages(1, page, false); | |
171 | } | |
172 | BUG_ON(blkif->free_pages_num == 0); | |
173 | page[0] = list_first_entry(&blkif->free_pages, struct page, lru); | |
174 | list_del(&page[0]->lru); | |
175 | blkif->free_pages_num--; | |
176 | spin_unlock_irqrestore(&blkif->free_pages_lock, flags); | |
efe08a3e | 177 | |
c6cc142d RPM |
178 | return 0; |
179 | } | |
180 | ||
181 | static inline void put_free_pages(struct xen_blkif *blkif, struct page **page, | |
182 | int num) | |
4d05a28d | 183 | { |
c6cc142d RPM |
184 | unsigned long flags; |
185 | int i; | |
186 | ||
187 | spin_lock_irqsave(&blkif->free_pages_lock, flags); | |
188 | for (i = 0; i < num; i++) | |
189 | list_add(&page[i]->lru, &blkif->free_pages); | |
190 | blkif->free_pages_num += num; | |
191 | spin_unlock_irqrestore(&blkif->free_pages_lock, flags); | |
192 | } | |
193 | ||
194 | static inline void shrink_free_pagepool(struct xen_blkif *blkif, int num) | |
195 | { | |
196 | /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */ | |
197 | struct page *page[NUM_BATCH_FREE_PAGES]; | |
198 | unsigned int num_pages = 0; | |
199 | unsigned long flags; | |
200 | ||
201 | spin_lock_irqsave(&blkif->free_pages_lock, flags); | |
202 | while (blkif->free_pages_num > num) { | |
203 | BUG_ON(list_empty(&blkif->free_pages)); | |
204 | page[num_pages] = list_first_entry(&blkif->free_pages, | |
205 | struct page, lru); | |
206 | list_del(&page[num_pages]->lru); | |
207 | blkif->free_pages_num--; | |
208 | if (++num_pages == NUM_BATCH_FREE_PAGES) { | |
209 | spin_unlock_irqrestore(&blkif->free_pages_lock, flags); | |
210 | free_xenballooned_pages(num_pages, page); | |
211 | spin_lock_irqsave(&blkif->free_pages_lock, flags); | |
212 | num_pages = 0; | |
213 | } | |
214 | } | |
215 | spin_unlock_irqrestore(&blkif->free_pages_lock, flags); | |
216 | if (num_pages != 0) | |
217 | free_xenballooned_pages(num_pages, page); | |
4d05a28d KRW |
218 | } |
219 | ||
c6cc142d RPM |
220 | #define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page))) |
221 | ||
4d05a28d | 222 | #define pending_handle(_req, _seg) \ |
bb6acb28 | 223 | (_req->grant_handles[_seg]) |
4d05a28d KRW |
224 | |
225 | ||
30fd1502 KRW |
226 | static int do_block_io_op(struct xen_blkif *blkif); |
227 | static int dispatch_rw_block_io(struct xen_blkif *blkif, | |
fc53bf75 KRW |
228 | struct blkif_request *req, |
229 | struct pending_req *pending_req); | |
30fd1502 | 230 | static void make_response(struct xen_blkif *blkif, u64 id, |
4d05a28d KRW |
231 | unsigned short op, int st); |
232 | ||
7dc34117 RPM |
233 | #define foreach_grant_safe(pos, n, rbtree, node) \ |
234 | for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \ | |
217fd5e7 | 235 | (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL; \ |
0a8704a5 | 236 | &(pos)->node != NULL; \ |
7dc34117 RPM |
237 | (pos) = container_of(n, typeof(*(pos)), node), \ |
238 | (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL) | |
0a8704a5 RPM |
239 | |
240 | ||
3f3aad5e RPM |
241 | /* |
242 | * We don't need locking around the persistent grant helpers | |
243 | * because blkback uses a single-thread for each backed, so we | |
244 | * can be sure that this functions will never be called recursively. | |
245 | * | |
246 | * The only exception to that is put_persistent_grant, that can be called | |
247 | * from interrupt context (by xen_blkbk_unmap), so we have to use atomic | |
248 | * bit operations to modify the flags of a persistent grant and to count | |
249 | * the number of used grants. | |
250 | */ | |
251 | static int add_persistent_gnt(struct xen_blkif *blkif, | |
0a8704a5 RPM |
252 | struct persistent_gnt *persistent_gnt) |
253 | { | |
3f3aad5e | 254 | struct rb_node **new = NULL, *parent = NULL; |
0a8704a5 RPM |
255 | struct persistent_gnt *this; |
256 | ||
3f3aad5e RPM |
257 | if (blkif->persistent_gnt_c >= xen_blkif_max_pgrants) { |
258 | if (!blkif->vbd.overflow_max_grants) | |
259 | blkif->vbd.overflow_max_grants = 1; | |
260 | return -EBUSY; | |
261 | } | |
0a8704a5 | 262 | /* Figure out where to put new node */ |
3f3aad5e | 263 | new = &blkif->persistent_gnts.rb_node; |
0a8704a5 RPM |
264 | while (*new) { |
265 | this = container_of(*new, struct persistent_gnt, node); | |
266 | ||
267 | parent = *new; | |
268 | if (persistent_gnt->gnt < this->gnt) | |
269 | new = &((*new)->rb_left); | |
270 | else if (persistent_gnt->gnt > this->gnt) | |
271 | new = &((*new)->rb_right); | |
272 | else { | |
c6cc142d RPM |
273 | pr_alert_ratelimited(DRV_PFX " trying to add a gref that's already in the tree\n"); |
274 | return -EINVAL; | |
0a8704a5 RPM |
275 | } |
276 | } | |
277 | ||
3f3aad5e RPM |
278 | bitmap_zero(persistent_gnt->flags, PERSISTENT_GNT_FLAGS_SIZE); |
279 | set_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags); | |
0a8704a5 RPM |
280 | /* Add new node and rebalance tree. */ |
281 | rb_link_node(&(persistent_gnt->node), parent, new); | |
3f3aad5e RPM |
282 | rb_insert_color(&(persistent_gnt->node), &blkif->persistent_gnts); |
283 | blkif->persistent_gnt_c++; | |
284 | atomic_inc(&blkif->persistent_gnt_in_use); | |
c6cc142d | 285 | return 0; |
0a8704a5 RPM |
286 | } |
287 | ||
3f3aad5e | 288 | static struct persistent_gnt *get_persistent_gnt(struct xen_blkif *blkif, |
0a8704a5 RPM |
289 | grant_ref_t gref) |
290 | { | |
291 | struct persistent_gnt *data; | |
3f3aad5e | 292 | struct rb_node *node = NULL; |
0a8704a5 | 293 | |
3f3aad5e | 294 | node = blkif->persistent_gnts.rb_node; |
0a8704a5 RPM |
295 | while (node) { |
296 | data = container_of(node, struct persistent_gnt, node); | |
297 | ||
298 | if (gref < data->gnt) | |
299 | node = node->rb_left; | |
300 | else if (gref > data->gnt) | |
301 | node = node->rb_right; | |
3f3aad5e RPM |
302 | else { |
303 | if(test_bit(PERSISTENT_GNT_ACTIVE, data->flags)) { | |
304 | pr_alert_ratelimited(DRV_PFX " requesting a grant already in use\n"); | |
305 | return NULL; | |
306 | } | |
307 | set_bit(PERSISTENT_GNT_ACTIVE, data->flags); | |
308 | atomic_inc(&blkif->persistent_gnt_in_use); | |
0a8704a5 | 309 | return data; |
3f3aad5e | 310 | } |
0a8704a5 RPM |
311 | } |
312 | return NULL; | |
313 | } | |
314 | ||
3f3aad5e RPM |
315 | static void put_persistent_gnt(struct xen_blkif *blkif, |
316 | struct persistent_gnt *persistent_gnt) | |
317 | { | |
318 | if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) | |
319 | pr_alert_ratelimited(DRV_PFX " freeing a grant already unused"); | |
320 | set_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); | |
321 | clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags); | |
322 | atomic_dec(&blkif->persistent_gnt_in_use); | |
323 | } | |
324 | ||
c6cc142d RPM |
325 | static void free_persistent_gnts(struct xen_blkif *blkif, struct rb_root *root, |
326 | unsigned int num) | |
4d4f270f RPM |
327 | { |
328 | struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
329 | struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
330 | struct persistent_gnt *persistent_gnt; | |
7dc34117 | 331 | struct rb_node *n; |
4d4f270f RPM |
332 | int ret = 0; |
333 | int segs_to_unmap = 0; | |
334 | ||
7dc34117 | 335 | foreach_grant_safe(persistent_gnt, n, root, node) { |
4d4f270f RPM |
336 | BUG_ON(persistent_gnt->handle == |
337 | BLKBACK_INVALID_HANDLE); | |
338 | gnttab_set_unmap_op(&unmap[segs_to_unmap], | |
339 | (unsigned long) pfn_to_kaddr(page_to_pfn( | |
340 | persistent_gnt->page)), | |
341 | GNTMAP_host_map, | |
342 | persistent_gnt->handle); | |
343 | ||
344 | pages[segs_to_unmap] = persistent_gnt->page; | |
4d4f270f RPM |
345 | |
346 | if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST || | |
347 | !rb_next(&persistent_gnt->node)) { | |
348 | ret = gnttab_unmap_refs(unmap, NULL, pages, | |
349 | segs_to_unmap); | |
350 | BUG_ON(ret); | |
c6cc142d | 351 | put_free_pages(blkif, pages, segs_to_unmap); |
4d4f270f RPM |
352 | segs_to_unmap = 0; |
353 | } | |
7dc34117 RPM |
354 | |
355 | rb_erase(&persistent_gnt->node, root); | |
356 | kfree(persistent_gnt); | |
357 | num--; | |
4d4f270f RPM |
358 | } |
359 | BUG_ON(num != 0); | |
360 | } | |
361 | ||
3f3aad5e RPM |
362 | static void unmap_purged_grants(struct work_struct *work) |
363 | { | |
364 | struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
365 | struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
366 | struct persistent_gnt *persistent_gnt; | |
367 | int ret, segs_to_unmap = 0; | |
368 | struct xen_blkif *blkif = container_of(work, typeof(*blkif), persistent_purge_work); | |
369 | ||
370 | while(!list_empty(&blkif->persistent_purge_list)) { | |
371 | persistent_gnt = list_first_entry(&blkif->persistent_purge_list, | |
372 | struct persistent_gnt, | |
373 | remove_node); | |
374 | list_del(&persistent_gnt->remove_node); | |
375 | ||
376 | gnttab_set_unmap_op(&unmap[segs_to_unmap], | |
377 | vaddr(persistent_gnt->page), | |
378 | GNTMAP_host_map, | |
379 | persistent_gnt->handle); | |
380 | ||
381 | pages[segs_to_unmap] = persistent_gnt->page; | |
382 | ||
383 | if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) { | |
384 | ret = gnttab_unmap_refs(unmap, NULL, pages, | |
385 | segs_to_unmap); | |
386 | BUG_ON(ret); | |
387 | put_free_pages(blkif, pages, segs_to_unmap); | |
388 | segs_to_unmap = 0; | |
389 | } | |
390 | kfree(persistent_gnt); | |
391 | } | |
392 | if (segs_to_unmap > 0) { | |
393 | ret = gnttab_unmap_refs(unmap, NULL, pages, segs_to_unmap); | |
394 | BUG_ON(ret); | |
395 | put_free_pages(blkif, pages, segs_to_unmap); | |
396 | } | |
397 | } | |
398 | ||
399 | static void purge_persistent_gnt(struct xen_blkif *blkif) | |
400 | { | |
401 | struct persistent_gnt *persistent_gnt; | |
402 | struct rb_node *n; | |
403 | unsigned int num_clean, total; | |
404 | bool scan_used = false; | |
405 | struct rb_root *root; | |
406 | ||
407 | if (blkif->persistent_gnt_c < xen_blkif_max_pgrants || | |
408 | (blkif->persistent_gnt_c == xen_blkif_max_pgrants && | |
409 | !blkif->vbd.overflow_max_grants)) { | |
410 | return; | |
411 | } | |
412 | ||
413 | if (work_pending(&blkif->persistent_purge_work)) { | |
414 | pr_alert_ratelimited(DRV_PFX "Scheduled work from previous purge is still pending, cannot purge list\n"); | |
415 | return; | |
416 | } | |
417 | ||
418 | num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN; | |
419 | num_clean = blkif->persistent_gnt_c - xen_blkif_max_pgrants + num_clean; | |
420 | num_clean = min(blkif->persistent_gnt_c, num_clean); | |
421 | if (num_clean > | |
422 | (blkif->persistent_gnt_c - | |
423 | atomic_read(&blkif->persistent_gnt_in_use))) | |
424 | return; | |
425 | ||
426 | /* | |
427 | * At this point, we can assure that there will be no calls | |
428 | * to get_persistent_grant (because we are executing this code from | |
429 | * xen_blkif_schedule), there can only be calls to put_persistent_gnt, | |
430 | * which means that the number of currently used grants will go down, | |
431 | * but never up, so we will always be able to remove the requested | |
432 | * number of grants. | |
433 | */ | |
434 | ||
435 | total = num_clean; | |
436 | ||
437 | pr_debug(DRV_PFX "Going to purge %u persistent grants\n", num_clean); | |
438 | ||
439 | INIT_LIST_HEAD(&blkif->persistent_purge_list); | |
440 | root = &blkif->persistent_gnts; | |
441 | purge_list: | |
442 | foreach_grant_safe(persistent_gnt, n, root, node) { | |
443 | BUG_ON(persistent_gnt->handle == | |
444 | BLKBACK_INVALID_HANDLE); | |
445 | ||
446 | if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags)) | |
447 | continue; | |
448 | if (!scan_used && | |
449 | (test_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags))) | |
450 | continue; | |
451 | ||
452 | rb_erase(&persistent_gnt->node, root); | |
453 | list_add(&persistent_gnt->remove_node, | |
454 | &blkif->persistent_purge_list); | |
455 | if (--num_clean == 0) | |
456 | goto finished; | |
457 | } | |
458 | /* | |
459 | * If we get here it means we also need to start cleaning | |
460 | * grants that were used since last purge in order to cope | |
461 | * with the requested num | |
462 | */ | |
463 | if (!scan_used) { | |
464 | pr_debug(DRV_PFX "Still missing %u purged frames\n", num_clean); | |
465 | scan_used = true; | |
466 | goto purge_list; | |
467 | } | |
468 | finished: | |
469 | /* Remove the "used" flag from all the persistent grants */ | |
470 | foreach_grant_safe(persistent_gnt, n, root, node) { | |
471 | BUG_ON(persistent_gnt->handle == | |
472 | BLKBACK_INVALID_HANDLE); | |
473 | clear_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags); | |
474 | } | |
475 | blkif->persistent_gnt_c -= (total - num_clean); | |
476 | blkif->vbd.overflow_max_grants = 0; | |
477 | ||
478 | /* We can defer this work */ | |
479 | INIT_WORK(&blkif->persistent_purge_work, unmap_purged_grants); | |
480 | schedule_work(&blkif->persistent_purge_work); | |
481 | pr_debug(DRV_PFX "Purged %u/%u\n", (total - num_clean), total); | |
482 | return; | |
483 | } | |
484 | ||
a1397fa3 KRW |
485 | /* |
486 | * Retrieve from the 'pending_reqs' a free pending_req structure to be used. | |
4d05a28d | 487 | */ |
2e9977c2 | 488 | static struct pending_req *alloc_req(void) |
4d05a28d | 489 | { |
2e9977c2 | 490 | struct pending_req *req = NULL; |
4d05a28d KRW |
491 | unsigned long flags; |
492 | ||
e8e28871 KRW |
493 | spin_lock_irqsave(&blkbk->pending_free_lock, flags); |
494 | if (!list_empty(&blkbk->pending_free)) { | |
2e9977c2 KRW |
495 | req = list_entry(blkbk->pending_free.next, struct pending_req, |
496 | free_list); | |
4d05a28d KRW |
497 | list_del(&req->free_list); |
498 | } | |
e8e28871 | 499 | spin_unlock_irqrestore(&blkbk->pending_free_lock, flags); |
4d05a28d KRW |
500 | return req; |
501 | } | |
502 | ||
a1397fa3 KRW |
503 | /* |
504 | * Return the 'pending_req' structure back to the freepool. We also | |
505 | * wake up the thread if it was waiting for a free page. | |
506 | */ | |
2e9977c2 | 507 | static void free_req(struct pending_req *req) |
4d05a28d KRW |
508 | { |
509 | unsigned long flags; | |
510 | int was_empty; | |
511 | ||
e8e28871 KRW |
512 | spin_lock_irqsave(&blkbk->pending_free_lock, flags); |
513 | was_empty = list_empty(&blkbk->pending_free); | |
514 | list_add(&req->free_list, &blkbk->pending_free); | |
515 | spin_unlock_irqrestore(&blkbk->pending_free_lock, flags); | |
4d05a28d | 516 | if (was_empty) |
e8e28871 | 517 | wake_up(&blkbk->pending_free_wq); |
4d05a28d KRW |
518 | } |
519 | ||
ee9ff853 KRW |
520 | /* |
521 | * Routines for managing virtual block devices (vbds). | |
522 | */ | |
3d814731 KRW |
523 | static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif, |
524 | int operation) | |
ee9ff853 | 525 | { |
3d814731 | 526 | struct xen_vbd *vbd = &blkif->vbd; |
ee9ff853 KRW |
527 | int rc = -EACCES; |
528 | ||
529 | if ((operation != READ) && vbd->readonly) | |
530 | goto out; | |
531 | ||
8ab52150 JB |
532 | if (likely(req->nr_sects)) { |
533 | blkif_sector_t end = req->sector_number + req->nr_sects; | |
534 | ||
535 | if (unlikely(end < req->sector_number)) | |
536 | goto out; | |
537 | if (unlikely(end > vbd_sz(vbd))) | |
538 | goto out; | |
539 | } | |
ee9ff853 KRW |
540 | |
541 | req->dev = vbd->pdevice; | |
542 | req->bdev = vbd->bdev; | |
543 | rc = 0; | |
544 | ||
545 | out: | |
546 | return rc; | |
547 | } | |
548 | ||
3d814731 | 549 | static void xen_vbd_resize(struct xen_blkif *blkif) |
ee9ff853 | 550 | { |
3d814731 | 551 | struct xen_vbd *vbd = &blkif->vbd; |
ee9ff853 KRW |
552 | struct xenbus_transaction xbt; |
553 | int err; | |
8b6bf747 | 554 | struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be); |
42c7841d | 555 | unsigned long long new_size = vbd_sz(vbd); |
ee9ff853 | 556 | |
22b20f2d | 557 | pr_info(DRV_PFX "VBD Resize: Domid: %d, Device: (%d, %d)\n", |
ee9ff853 | 558 | blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice)); |
22b20f2d | 559 | pr_info(DRV_PFX "VBD Resize: new size %llu\n", new_size); |
ee9ff853 KRW |
560 | vbd->size = new_size; |
561 | again: | |
562 | err = xenbus_transaction_start(&xbt); | |
563 | if (err) { | |
22b20f2d | 564 | pr_warn(DRV_PFX "Error starting transaction"); |
ee9ff853 KRW |
565 | return; |
566 | } | |
567 | err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu", | |
42c7841d | 568 | (unsigned long long)vbd_sz(vbd)); |
ee9ff853 | 569 | if (err) { |
22b20f2d | 570 | pr_warn(DRV_PFX "Error writing new size"); |
ee9ff853 KRW |
571 | goto abort; |
572 | } | |
573 | /* | |
574 | * Write the current state; we will use this to synchronize | |
575 | * the front-end. If the current state is "connected" the | |
576 | * front-end will get the new size information online. | |
577 | */ | |
578 | err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state); | |
579 | if (err) { | |
22b20f2d | 580 | pr_warn(DRV_PFX "Error writing the state"); |
ee9ff853 KRW |
581 | goto abort; |
582 | } | |
583 | ||
584 | err = xenbus_transaction_end(xbt, 0); | |
585 | if (err == -EAGAIN) | |
586 | goto again; | |
587 | if (err) | |
22b20f2d | 588 | pr_warn(DRV_PFX "Error ending transaction"); |
496b318e | 589 | return; |
ee9ff853 KRW |
590 | abort: |
591 | xenbus_transaction_end(xbt, 1); | |
592 | } | |
593 | ||
a1397fa3 | 594 | /* |
b0aef179 KRW |
595 | * Notification from the guest OS. |
596 | */ | |
30fd1502 | 597 | static void blkif_notify_work(struct xen_blkif *blkif) |
4d05a28d | 598 | { |
b0aef179 KRW |
599 | blkif->waiting_reqs = 1; |
600 | wake_up(&blkif->wq); | |
601 | } | |
4d05a28d | 602 | |
8b6bf747 | 603 | irqreturn_t xen_blkif_be_int(int irq, void *dev_id) |
b0aef179 KRW |
604 | { |
605 | blkif_notify_work(dev_id); | |
606 | return IRQ_HANDLED; | |
4d05a28d KRW |
607 | } |
608 | ||
2e9977c2 | 609 | /* |
4d05a28d KRW |
610 | * SCHEDULER FUNCTIONS |
611 | */ | |
612 | ||
30fd1502 | 613 | static void print_stats(struct xen_blkif *blkif) |
4d05a28d | 614 | { |
986cacbd | 615 | pr_info("xen-blkback (%s): oo %3llu | rd %4llu | wr %4llu | f %4llu" |
3f3aad5e | 616 | " | ds %4llu | pg: %4u/%4d\n", |
ebe81906 | 617 | current->comm, blkif->st_oo_req, |
b3cb0d6a | 618 | blkif->st_rd_req, blkif->st_wr_req, |
c1a15d08 RPM |
619 | blkif->st_f_req, blkif->st_ds_req, |
620 | blkif->persistent_gnt_c, | |
3f3aad5e | 621 | xen_blkif_max_pgrants); |
4d05a28d KRW |
622 | blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000); |
623 | blkif->st_rd_req = 0; | |
624 | blkif->st_wr_req = 0; | |
625 | blkif->st_oo_req = 0; | |
b3cb0d6a | 626 | blkif->st_ds_req = 0; |
4d05a28d KRW |
627 | } |
628 | ||
8b6bf747 | 629 | int xen_blkif_schedule(void *arg) |
4d05a28d | 630 | { |
30fd1502 | 631 | struct xen_blkif *blkif = arg; |
3d814731 | 632 | struct xen_vbd *vbd = &blkif->vbd; |
3f3aad5e | 633 | unsigned long timeout; |
4d05a28d | 634 | |
8b6bf747 | 635 | xen_blkif_get(blkif); |
4d05a28d | 636 | |
4d05a28d KRW |
637 | while (!kthread_should_stop()) { |
638 | if (try_to_freeze()) | |
639 | continue; | |
42c7841d | 640 | if (unlikely(vbd->size != vbd_sz(vbd))) |
3d814731 | 641 | xen_vbd_resize(blkif); |
4d05a28d | 642 | |
3f3aad5e RPM |
643 | timeout = msecs_to_jiffies(LRU_INTERVAL); |
644 | ||
645 | timeout = wait_event_interruptible_timeout( | |
4d05a28d | 646 | blkif->wq, |
3f3aad5e RPM |
647 | blkif->waiting_reqs || kthread_should_stop(), |
648 | timeout); | |
649 | if (timeout == 0) | |
650 | goto purge_gnt_list; | |
651 | timeout = wait_event_interruptible_timeout( | |
e8e28871 | 652 | blkbk->pending_free_wq, |
2e9977c2 | 653 | !list_empty(&blkbk->pending_free) || |
3f3aad5e RPM |
654 | kthread_should_stop(), |
655 | timeout); | |
656 | if (timeout == 0) | |
657 | goto purge_gnt_list; | |
4d05a28d KRW |
658 | |
659 | blkif->waiting_reqs = 0; | |
660 | smp_mb(); /* clear flag *before* checking for work */ | |
661 | ||
662 | if (do_block_io_op(blkif)) | |
663 | blkif->waiting_reqs = 1; | |
4d05a28d | 664 | |
3f3aad5e RPM |
665 | purge_gnt_list: |
666 | if (blkif->vbd.feature_gnt_persistent && | |
667 | time_after(jiffies, blkif->next_lru)) { | |
668 | purge_persistent_gnt(blkif); | |
669 | blkif->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL); | |
670 | } | |
671 | ||
c6cc142d RPM |
672 | /* Shrink if we have more than xen_blkif_max_buffer_pages */ |
673 | shrink_free_pagepool(blkif, xen_blkif_max_buffer_pages); | |
674 | ||
4d05a28d KRW |
675 | if (log_stats && time_after(jiffies, blkif->st_print)) |
676 | print_stats(blkif); | |
677 | } | |
678 | ||
c6cc142d RPM |
679 | /* Since we are shutting down remove all pages from the buffer */ |
680 | shrink_free_pagepool(blkif, 0 /* All */); | |
681 | ||
0a8704a5 | 682 | /* Free all persistent grant pages */ |
4d4f270f | 683 | if (!RB_EMPTY_ROOT(&blkif->persistent_gnts)) |
c6cc142d | 684 | free_persistent_gnts(blkif, &blkif->persistent_gnts, |
4d4f270f | 685 | blkif->persistent_gnt_c); |
0a8704a5 | 686 | |
0a8704a5 | 687 | BUG_ON(!RB_EMPTY_ROOT(&blkif->persistent_gnts)); |
4d4f270f | 688 | blkif->persistent_gnt_c = 0; |
0a8704a5 | 689 | |
4d05a28d KRW |
690 | if (log_stats) |
691 | print_stats(blkif); | |
4d05a28d KRW |
692 | |
693 | blkif->xenblkd = NULL; | |
8b6bf747 | 694 | xen_blkif_put(blkif); |
4d05a28d KRW |
695 | |
696 | return 0; | |
697 | } | |
698 | ||
1a95fe6e | 699 | struct seg_buf { |
ffb1dabd | 700 | unsigned int offset; |
1a95fe6e KRW |
701 | unsigned int nsec; |
702 | }; | |
b0aef179 KRW |
703 | /* |
704 | * Unmap the grant references, and also remove the M2P over-rides | |
705 | * used in the 'pending_req'. | |
01f37f2d | 706 | */ |
9f3aedf5 | 707 | static void xen_blkbk_unmap(struct pending_req *req) |
b0aef179 KRW |
708 | { |
709 | struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
4f14faaa | 710 | struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
b0aef179 KRW |
711 | unsigned int i, invcount = 0; |
712 | grant_handle_t handle; | |
c6cc142d | 713 | struct xen_blkif *blkif = req->blkif; |
b0aef179 KRW |
714 | int ret; |
715 | ||
716 | for (i = 0; i < req->nr_pages; i++) { | |
3f3aad5e RPM |
717 | if (req->persistent_gnts[i] != NULL) { |
718 | put_persistent_gnt(blkif, req->persistent_gnts[i]); | |
0a8704a5 | 719 | continue; |
3f3aad5e | 720 | } |
b0aef179 | 721 | handle = pending_handle(req, i); |
c6cc142d | 722 | pages[invcount] = req->pages[i]; |
b0aef179 KRW |
723 | if (handle == BLKBACK_INVALID_HANDLE) |
724 | continue; | |
c6cc142d | 725 | gnttab_set_unmap_op(&unmap[invcount], vaddr(pages[invcount]), |
b0aef179 KRW |
726 | GNTMAP_host_map, handle); |
727 | pending_handle(req, i) = BLKBACK_INVALID_HANDLE; | |
728 | invcount++; | |
729 | } | |
730 | ||
2fc136ee | 731 | ret = gnttab_unmap_refs(unmap, NULL, pages, invcount); |
b0aef179 | 732 | BUG_ON(ret); |
c6cc142d | 733 | put_free_pages(blkif, pages, invcount); |
b0aef179 | 734 | } |
01f37f2d KRW |
735 | |
736 | static int xen_blkbk_map(struct blkif_request *req, | |
737 | struct pending_req *pending_req, | |
0a8704a5 RPM |
738 | struct seg_buf seg[], |
739 | struct page *pages[]) | |
1a95fe6e KRW |
740 | { |
741 | struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST]; | |
0a8704a5 | 742 | struct page *pages_to_gnt[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
3f3aad5e | 743 | struct persistent_gnt **persistent_gnts = pending_req->persistent_gnts; |
0a8704a5 RPM |
744 | struct persistent_gnt *persistent_gnt = NULL; |
745 | struct xen_blkif *blkif = pending_req->blkif; | |
746 | phys_addr_t addr = 0; | |
c6cc142d | 747 | int i, seg_idx, new_map_idx; |
97e36834 | 748 | int nseg = req->u.rw.nr_segments; |
0a8704a5 | 749 | int segs_to_map = 0; |
1a95fe6e | 750 | int ret = 0; |
0a8704a5 RPM |
751 | int use_persistent_gnts; |
752 | ||
753 | use_persistent_gnts = (blkif->vbd.feature_gnt_persistent); | |
754 | ||
01f37f2d KRW |
755 | /* |
756 | * Fill out preq.nr_sects with proper amount of sectors, and setup | |
1a95fe6e KRW |
757 | * assign map[..] with the PFN of the page in our domain with the |
758 | * corresponding grant reference for each page. | |
759 | */ | |
760 | for (i = 0; i < nseg; i++) { | |
761 | uint32_t flags; | |
762 | ||
0a8704a5 RPM |
763 | if (use_persistent_gnts) |
764 | persistent_gnt = get_persistent_gnt( | |
3f3aad5e | 765 | blkif, |
0a8704a5 RPM |
766 | req->u.rw.seg[i].gref); |
767 | ||
768 | if (persistent_gnt) { | |
769 | /* | |
770 | * We are using persistent grants and | |
771 | * the grant is already mapped | |
772 | */ | |
0a8704a5 RPM |
773 | pages[i] = persistent_gnt->page; |
774 | persistent_gnts[i] = persistent_gnt; | |
775 | } else { | |
c6cc142d RPM |
776 | if (get_free_page(blkif, &pages[i])) |
777 | goto out_of_memory; | |
778 | addr = vaddr(pages[i]); | |
779 | pages_to_gnt[segs_to_map] = pages[i]; | |
0a8704a5 | 780 | persistent_gnts[i] = NULL; |
0a8704a5 | 781 | flags = GNTMAP_host_map; |
c6cc142d | 782 | if (!use_persistent_gnts && |
0a8704a5 RPM |
783 | (pending_req->operation != BLKIF_OP_READ)) |
784 | flags |= GNTMAP_readonly; | |
785 | gnttab_set_map_op(&map[segs_to_map++], addr, | |
786 | flags, req->u.rw.seg[i].gref, | |
787 | blkif->domid); | |
788 | } | |
1a95fe6e KRW |
789 | } |
790 | ||
0a8704a5 RPM |
791 | if (segs_to_map) { |
792 | ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map); | |
793 | BUG_ON(ret); | |
794 | } | |
1a95fe6e | 795 | |
01f37f2d KRW |
796 | /* |
797 | * Now swizzle the MFN in our domain with the MFN from the other domain | |
1a95fe6e KRW |
798 | * so that when we access vaddr(pending_req,i) it has the contents of |
799 | * the page from the other domain. | |
800 | */ | |
c6cc142d RPM |
801 | for (seg_idx = 0, new_map_idx = 0; seg_idx < nseg; seg_idx++) { |
802 | if (!persistent_gnts[seg_idx]) { | |
0a8704a5 | 803 | /* This is a newly mapped grant */ |
c6cc142d RPM |
804 | BUG_ON(new_map_idx >= segs_to_map); |
805 | if (unlikely(map[new_map_idx].status != 0)) { | |
0a8704a5 | 806 | pr_debug(DRV_PFX "invalid buffer -- could not remap it\n"); |
c6cc142d | 807 | pending_handle(pending_req, seg_idx) = BLKBACK_INVALID_HANDLE; |
0a8704a5 | 808 | ret |= 1; |
c6cc142d RPM |
809 | new_map_idx++; |
810 | /* | |
811 | * No need to set unmap_seg bit, since | |
812 | * we can not unmap this grant because | |
813 | * the handle is invalid. | |
814 | */ | |
815 | continue; | |
0a8704a5 | 816 | } |
c6cc142d RPM |
817 | pending_handle(pending_req, seg_idx) = map[new_map_idx].handle; |
818 | } else { | |
819 | /* This grant is persistent and already mapped */ | |
820 | goto next; | |
0a8704a5 | 821 | } |
c6cc142d | 822 | if (use_persistent_gnts && |
3f3aad5e | 823 | blkif->persistent_gnt_c < xen_blkif_max_pgrants) { |
c6cc142d RPM |
824 | /* |
825 | * We are using persistent grants, the grant is | |
3f3aad5e | 826 | * not mapped but we might have room for it. |
c6cc142d RPM |
827 | */ |
828 | persistent_gnt = kmalloc(sizeof(struct persistent_gnt), | |
829 | GFP_KERNEL); | |
830 | if (!persistent_gnt) { | |
0a8704a5 | 831 | /* |
c6cc142d RPM |
832 | * If we don't have enough memory to |
833 | * allocate the persistent_gnt struct | |
834 | * map this grant non-persistenly | |
0a8704a5 | 835 | */ |
c6cc142d | 836 | goto next_unmap; |
0a8704a5 | 837 | } |
c6cc142d RPM |
838 | persistent_gnt->gnt = map[new_map_idx].ref; |
839 | persistent_gnt->handle = map[new_map_idx].handle; | |
840 | persistent_gnt->page = pages[seg_idx]; | |
3f3aad5e | 841 | if (add_persistent_gnt(blkif, |
c6cc142d RPM |
842 | persistent_gnt)) { |
843 | kfree(persistent_gnt); | |
844 | persistent_gnt = NULL; | |
845 | goto next_unmap; | |
846 | } | |
3f3aad5e | 847 | persistent_gnts[seg_idx] = persistent_gnt; |
c6cc142d RPM |
848 | pr_debug(DRV_PFX " grant %u added to the tree of persistent grants, using %u/%u\n", |
849 | persistent_gnt->gnt, blkif->persistent_gnt_c, | |
3f3aad5e | 850 | xen_blkif_max_pgrants); |
c6cc142d RPM |
851 | new_map_idx++; |
852 | goto next; | |
853 | } | |
854 | if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) { | |
855 | blkif->vbd.overflow_max_grants = 1; | |
856 | pr_debug(DRV_PFX " domain %u, device %#x is using maximum number of persistent grants\n", | |
857 | blkif->domid, blkif->vbd.handle); | |
1a95fe6e | 858 | } |
c6cc142d RPM |
859 | next_unmap: |
860 | /* | |
861 | * We could not map this grant persistently, so use it as | |
862 | * a non-persistent grant. | |
863 | */ | |
c6cc142d RPM |
864 | new_map_idx++; |
865 | next: | |
866 | seg[seg_idx].offset = (req->u.rw.seg[seg_idx].first_sect << 9); | |
1a95fe6e KRW |
867 | } |
868 | return ret; | |
c6cc142d RPM |
869 | |
870 | out_of_memory: | |
871 | pr_alert(DRV_PFX "%s: out of memory\n", __func__); | |
872 | put_free_pages(blkif, pages_to_gnt, segs_to_map); | |
873 | return -ENOMEM; | |
1a95fe6e KRW |
874 | } |
875 | ||
42146352 KRW |
876 | static int dispatch_discard_io(struct xen_blkif *blkif, |
877 | struct blkif_request *req) | |
b3cb0d6a LD |
878 | { |
879 | int err = 0; | |
880 | int status = BLKIF_RSP_OKAY; | |
881 | struct block_device *bdev = blkif->vbd.bdev; | |
4dae7670 | 882 | unsigned long secure; |
b3cb0d6a | 883 | |
42146352 KRW |
884 | blkif->st_ds_req++; |
885 | ||
886 | xen_blkif_get(blkif); | |
4dae7670 KRW |
887 | secure = (blkif->vbd.discard_secure && |
888 | (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ? | |
889 | BLKDEV_DISCARD_SECURE : 0; | |
890 | ||
891 | err = blkdev_issue_discard(bdev, req->u.discard.sector_number, | |
892 | req->u.discard.nr_sectors, | |
893 | GFP_KERNEL, secure); | |
b3cb0d6a LD |
894 | |
895 | if (err == -EOPNOTSUPP) { | |
896 | pr_debug(DRV_PFX "discard op failed, not supported\n"); | |
897 | status = BLKIF_RSP_EOPNOTSUPP; | |
898 | } else if (err) | |
899 | status = BLKIF_RSP_ERROR; | |
900 | ||
97e36834 | 901 | make_response(blkif, req->u.discard.id, req->operation, status); |
42146352 KRW |
902 | xen_blkif_put(blkif); |
903 | return err; | |
b3cb0d6a LD |
904 | } |
905 | ||
0e367ae4 DV |
906 | static int dispatch_other_io(struct xen_blkif *blkif, |
907 | struct blkif_request *req, | |
908 | struct pending_req *pending_req) | |
909 | { | |
910 | free_req(pending_req); | |
911 | make_response(blkif, req->u.other.id, req->operation, | |
912 | BLKIF_RSP_EOPNOTSUPP); | |
913 | return -EIO; | |
914 | } | |
915 | ||
29bde093 KRW |
916 | static void xen_blk_drain_io(struct xen_blkif *blkif) |
917 | { | |
918 | atomic_set(&blkif->drain, 1); | |
919 | do { | |
6927d920 KRW |
920 | /* The initial value is one, and one refcnt taken at the |
921 | * start of the xen_blkif_schedule thread. */ | |
922 | if (atomic_read(&blkif->refcnt) <= 2) | |
923 | break; | |
29bde093 KRW |
924 | wait_for_completion_interruptible_timeout( |
925 | &blkif->drain_complete, HZ); | |
926 | ||
927 | if (!atomic_read(&blkif->drain)) | |
928 | break; | |
29bde093 KRW |
929 | } while (!kthread_should_stop()); |
930 | atomic_set(&blkif->drain, 0); | |
931 | } | |
932 | ||
a1397fa3 KRW |
933 | /* |
934 | * Completion callback on the bio's. Called as bh->b_end_io() | |
4d05a28d KRW |
935 | */ |
936 | ||
2e9977c2 | 937 | static void __end_block_io_op(struct pending_req *pending_req, int error) |
4d05a28d KRW |
938 | { |
939 | /* An error fails the entire request. */ | |
24f567f9 | 940 | if ((pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE) && |
4d05a28d | 941 | (error == -EOPNOTSUPP)) { |
22b20f2d | 942 | pr_debug(DRV_PFX "flush diskcache op failed, not supported\n"); |
24f567f9 | 943 | xen_blkbk_flush_diskcache(XBT_NIL, pending_req->blkif->be, 0); |
4d05a28d | 944 | pending_req->status = BLKIF_RSP_EOPNOTSUPP; |
29bde093 KRW |
945 | } else if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) && |
946 | (error == -EOPNOTSUPP)) { | |
947 | pr_debug(DRV_PFX "write barrier op failed, not supported\n"); | |
948 | xen_blkbk_barrier(XBT_NIL, pending_req->blkif->be, 0); | |
949 | pending_req->status = BLKIF_RSP_EOPNOTSUPP; | |
4d05a28d | 950 | } else if (error) { |
22b20f2d | 951 | pr_debug(DRV_PFX "Buffer not up-to-date at end of operation," |
ebe81906 | 952 | " error=%d\n", error); |
4d05a28d KRW |
953 | pending_req->status = BLKIF_RSP_ERROR; |
954 | } | |
955 | ||
01f37f2d KRW |
956 | /* |
957 | * If all of the bio's have completed it is time to unmap | |
a1397fa3 | 958 | * the grant references associated with 'request' and provide |
2e9977c2 KRW |
959 | * the proper response on the ring. |
960 | */ | |
4d05a28d | 961 | if (atomic_dec_and_test(&pending_req->pendcnt)) { |
9f3aedf5 | 962 | xen_blkbk_unmap(pending_req); |
4d05a28d KRW |
963 | make_response(pending_req->blkif, pending_req->id, |
964 | pending_req->operation, pending_req->status); | |
8b6bf747 | 965 | xen_blkif_put(pending_req->blkif); |
29bde093 KRW |
966 | if (atomic_read(&pending_req->blkif->refcnt) <= 2) { |
967 | if (atomic_read(&pending_req->blkif->drain)) | |
968 | complete(&pending_req->blkif->drain_complete); | |
969 | } | |
4d05a28d KRW |
970 | free_req(pending_req); |
971 | } | |
972 | } | |
973 | ||
a1397fa3 KRW |
974 | /* |
975 | * bio callback. | |
976 | */ | |
88122933 | 977 | static void end_block_io_op(struct bio *bio, int error) |
4d05a28d | 978 | { |
4d05a28d KRW |
979 | __end_block_io_op(bio->bi_private, error); |
980 | bio_put(bio); | |
4d05a28d KRW |
981 | } |
982 | ||
983 | ||
4d05a28d | 984 | |
a1397fa3 KRW |
985 | /* |
986 | * Function to copy the from the ring buffer the 'struct blkif_request' | |
987 | * (which has the sectors we want, number of them, grant references, etc), | |
988 | * and transmute it to the block API to hand it over to the proper block disk. | |
4d05a28d | 989 | */ |
b4726a9d DS |
990 | static int |
991 | __do_block_io_op(struct xen_blkif *blkif) | |
4d05a28d | 992 | { |
88122933 JF |
993 | union blkif_back_rings *blk_rings = &blkif->blk_rings; |
994 | struct blkif_request req; | |
2e9977c2 | 995 | struct pending_req *pending_req; |
4d05a28d KRW |
996 | RING_IDX rc, rp; |
997 | int more_to_do = 0; | |
998 | ||
999 | rc = blk_rings->common.req_cons; | |
1000 | rp = blk_rings->common.sring->req_prod; | |
1001 | rmb(); /* Ensure we see queued requests up to 'rp'. */ | |
1002 | ||
1003 | while (rc != rp) { | |
1004 | ||
1005 | if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc)) | |
1006 | break; | |
1007 | ||
8270b45b | 1008 | if (kthread_should_stop()) { |
4d05a28d KRW |
1009 | more_to_do = 1; |
1010 | break; | |
1011 | } | |
1012 | ||
8270b45b KF |
1013 | pending_req = alloc_req(); |
1014 | if (NULL == pending_req) { | |
1015 | blkif->st_oo_req++; | |
4d05a28d KRW |
1016 | more_to_do = 1; |
1017 | break; | |
1018 | } | |
1019 | ||
1020 | switch (blkif->blk_protocol) { | |
1021 | case BLKIF_PROTOCOL_NATIVE: | |
1022 | memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req)); | |
1023 | break; | |
1024 | case BLKIF_PROTOCOL_X86_32: | |
1025 | blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc)); | |
1026 | break; | |
1027 | case BLKIF_PROTOCOL_X86_64: | |
1028 | blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc)); | |
1029 | break; | |
1030 | default: | |
1031 | BUG(); | |
1032 | } | |
1033 | blk_rings->common.req_cons = ++rc; /* before make_response() */ | |
1034 | ||
1035 | /* Apply all sanity checks to /private copy/ of request. */ | |
1036 | barrier(); | |
0e367ae4 DV |
1037 | |
1038 | switch (req.operation) { | |
1039 | case BLKIF_OP_READ: | |
1040 | case BLKIF_OP_WRITE: | |
1041 | case BLKIF_OP_WRITE_BARRIER: | |
1042 | case BLKIF_OP_FLUSH_DISKCACHE: | |
1043 | if (dispatch_rw_block_io(blkif, &req, pending_req)) | |
1044 | goto done; | |
1045 | break; | |
1046 | case BLKIF_OP_DISCARD: | |
42146352 KRW |
1047 | free_req(pending_req); |
1048 | if (dispatch_discard_io(blkif, &req)) | |
0e367ae4 | 1049 | goto done; |
4d05a28d | 1050 | break; |
0e367ae4 DV |
1051 | default: |
1052 | if (dispatch_other_io(blkif, &req, pending_req)) | |
1053 | goto done; | |
1054 | break; | |
1055 | } | |
4d05a28d KRW |
1056 | |
1057 | /* Yield point for this unbounded loop. */ | |
1058 | cond_resched(); | |
1059 | } | |
0e367ae4 | 1060 | done: |
4d05a28d KRW |
1061 | return more_to_do; |
1062 | } | |
1063 | ||
b4726a9d DS |
1064 | static int |
1065 | do_block_io_op(struct xen_blkif *blkif) | |
1066 | { | |
1067 | union blkif_back_rings *blk_rings = &blkif->blk_rings; | |
1068 | int more_to_do; | |
1069 | ||
1070 | do { | |
1071 | more_to_do = __do_block_io_op(blkif); | |
1072 | if (more_to_do) | |
1073 | break; | |
1074 | ||
1075 | RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do); | |
1076 | } while (more_to_do); | |
1077 | ||
1078 | return more_to_do; | |
1079 | } | |
a1397fa3 | 1080 | /* |
01f37f2d KRW |
1081 | * Transmutation of the 'struct blkif_request' to a proper 'struct bio' |
1082 | * and call the 'submit_bio' to pass it to the underlying storage. | |
a1397fa3 | 1083 | */ |
30fd1502 KRW |
1084 | static int dispatch_rw_block_io(struct xen_blkif *blkif, |
1085 | struct blkif_request *req, | |
1086 | struct pending_req *pending_req) | |
4d05a28d | 1087 | { |
4d05a28d | 1088 | struct phys_req preq; |
1a95fe6e | 1089 | struct seg_buf seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
4d05a28d KRW |
1090 | unsigned int nseg; |
1091 | struct bio *bio = NULL; | |
77089926 | 1092 | struct bio *biolist[BLKIF_MAX_SEGMENTS_PER_REQUEST]; |
1a95fe6e | 1093 | int i, nbio = 0; |
4d05a28d | 1094 | int operation; |
a19be5f0 | 1095 | struct blk_plug plug; |
29bde093 | 1096 | bool drain = false; |
c6cc142d | 1097 | struct page **pages = pending_req->pages; |
4d05a28d KRW |
1098 | |
1099 | switch (req->operation) { | |
1100 | case BLKIF_OP_READ: | |
fc53bf75 | 1101 | blkif->st_rd_req++; |
4d05a28d KRW |
1102 | operation = READ; |
1103 | break; | |
1104 | case BLKIF_OP_WRITE: | |
fc53bf75 | 1105 | blkif->st_wr_req++; |
013c3ca1 | 1106 | operation = WRITE_ODIRECT; |
4d05a28d | 1107 | break; |
29bde093 KRW |
1108 | case BLKIF_OP_WRITE_BARRIER: |
1109 | drain = true; | |
24f567f9 | 1110 | case BLKIF_OP_FLUSH_DISKCACHE: |
fc53bf75 | 1111 | blkif->st_f_req++; |
24f567f9 | 1112 | operation = WRITE_FLUSH; |
4d05a28d KRW |
1113 | break; |
1114 | default: | |
1115 | operation = 0; /* make gcc happy */ | |
fc53bf75 KRW |
1116 | goto fail_response; |
1117 | break; | |
4d05a28d KRW |
1118 | } |
1119 | ||
42146352 KRW |
1120 | /* Check that the number of segments is sane. */ |
1121 | nseg = req->u.rw.nr_segments; | |
97e36834 | 1122 | |
42146352 | 1123 | if (unlikely(nseg == 0 && operation != WRITE_FLUSH) || |
4d05a28d | 1124 | unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) { |
22b20f2d | 1125 | pr_debug(DRV_PFX "Bad number of segments in request (%d)\n", |
ebe81906 | 1126 | nseg); |
1a95fe6e | 1127 | /* Haven't submitted any bio's yet. */ |
4d05a28d KRW |
1128 | goto fail_response; |
1129 | } | |
1130 | ||
c35950bf | 1131 | preq.sector_number = req->u.rw.sector_number; |
4d05a28d KRW |
1132 | preq.nr_sects = 0; |
1133 | ||
1134 | pending_req->blkif = blkif; | |
97e36834 | 1135 | pending_req->id = req->u.rw.id; |
4d05a28d KRW |
1136 | pending_req->operation = req->operation; |
1137 | pending_req->status = BLKIF_RSP_OKAY; | |
1138 | pending_req->nr_pages = nseg; | |
e9350493 | 1139 | |
4d05a28d | 1140 | for (i = 0; i < nseg; i++) { |
c35950bf KRW |
1141 | seg[i].nsec = req->u.rw.seg[i].last_sect - |
1142 | req->u.rw.seg[i].first_sect + 1; | |
c35950bf KRW |
1143 | if ((req->u.rw.seg[i].last_sect >= (PAGE_SIZE >> 9)) || |
1144 | (req->u.rw.seg[i].last_sect < req->u.rw.seg[i].first_sect)) | |
4d05a28d KRW |
1145 | goto fail_response; |
1146 | preq.nr_sects += seg[i].nsec; | |
976222e0 | 1147 | |
4d05a28d KRW |
1148 | } |
1149 | ||
3d814731 | 1150 | if (xen_vbd_translate(&preq, blkif, operation) != 0) { |
22b20f2d | 1151 | pr_debug(DRV_PFX "access denied: %s of [%llu,%llu] on dev=%04x\n", |
ebe81906 KRW |
1152 | operation == READ ? "read" : "write", |
1153 | preq.sector_number, | |
a72d9002 CG |
1154 | preq.sector_number + preq.nr_sects, |
1155 | blkif->vbd.pdevice); | |
1a95fe6e | 1156 | goto fail_response; |
4d05a28d | 1157 | } |
01f37f2d KRW |
1158 | |
1159 | /* | |
3d814731 | 1160 | * This check _MUST_ be done after xen_vbd_translate as the preq.bdev |
01f37f2d KRW |
1161 | * is set there. |
1162 | */ | |
e9350493 KRW |
1163 | for (i = 0; i < nseg; i++) { |
1164 | if (((int)preq.sector_number|(int)seg[i].nsec) & | |
1165 | ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) { | |
22b20f2d | 1166 | pr_debug(DRV_PFX "Misaligned I/O request from domain %d", |
ebe81906 | 1167 | blkif->domid); |
e9350493 KRW |
1168 | goto fail_response; |
1169 | } | |
1170 | } | |
01f37f2d | 1171 | |
29bde093 KRW |
1172 | /* Wait on all outstanding I/O's and once that has been completed |
1173 | * issue the WRITE_FLUSH. | |
1174 | */ | |
1175 | if (drain) | |
1176 | xen_blk_drain_io(pending_req->blkif); | |
1177 | ||
01f37f2d KRW |
1178 | /* |
1179 | * If we have failed at this point, we need to undo the M2P override, | |
2e9977c2 KRW |
1180 | * set gnttab_set_unmap_op on all of the grant references and perform |
1181 | * the hypercall to unmap the grants - that is all done in | |
9f3aedf5 | 1182 | * xen_blkbk_unmap. |
2e9977c2 | 1183 | */ |
0a8704a5 | 1184 | if (xen_blkbk_map(req, pending_req, seg, pages)) |
4d05a28d KRW |
1185 | goto fail_flush; |
1186 | ||
b3cb0d6a LD |
1187 | /* |
1188 | * This corresponding xen_blkif_put is done in __end_block_io_op, or | |
1189 | * below (in "!bio") if we are handling a BLKIF_OP_DISCARD. | |
1190 | */ | |
8b6bf747 | 1191 | xen_blkif_get(blkif); |
4d05a28d KRW |
1192 | |
1193 | for (i = 0; i < nseg; i++) { | |
4d05a28d KRW |
1194 | while ((bio == NULL) || |
1195 | (bio_add_page(bio, | |
0a8704a5 | 1196 | pages[i], |
4d05a28d | 1197 | seg[i].nsec << 9, |
ffb1dabd | 1198 | seg[i].offset) == 0)) { |
2e9977c2 | 1199 | |
03e0edf9 | 1200 | bio = bio_alloc(GFP_KERNEL, nseg-i); |
4d05a28d KRW |
1201 | if (unlikely(bio == NULL)) |
1202 | goto fail_put_bio; | |
1203 | ||
03e0edf9 | 1204 | biolist[nbio++] = bio; |
4d05a28d KRW |
1205 | bio->bi_bdev = preq.bdev; |
1206 | bio->bi_private = pending_req; | |
1207 | bio->bi_end_io = end_block_io_op; | |
1208 | bio->bi_sector = preq.sector_number; | |
1209 | } | |
1210 | ||
1211 | preq.sector_number += seg[i].nsec; | |
1212 | } | |
1213 | ||
b3cb0d6a | 1214 | /* This will be hit if the operation was a flush or discard. */ |
4d05a28d | 1215 | if (!bio) { |
42146352 | 1216 | BUG_ON(operation != WRITE_FLUSH); |
b0f80127 | 1217 | |
42146352 KRW |
1218 | bio = bio_alloc(GFP_KERNEL, 0); |
1219 | if (unlikely(bio == NULL)) | |
1220 | goto fail_put_bio; | |
4d05a28d | 1221 | |
42146352 KRW |
1222 | biolist[nbio++] = bio; |
1223 | bio->bi_bdev = preq.bdev; | |
1224 | bio->bi_private = pending_req; | |
1225 | bio->bi_end_io = end_block_io_op; | |
4d05a28d KRW |
1226 | } |
1227 | ||
77089926 | 1228 | atomic_set(&pending_req->pendcnt, nbio); |
a19be5f0 KRW |
1229 | blk_start_plug(&plug); |
1230 | ||
77089926 KRW |
1231 | for (i = 0; i < nbio; i++) |
1232 | submit_bio(operation, biolist[i]); | |
1233 | ||
a19be5f0 | 1234 | /* Let the I/Os go.. */ |
3d68b399 | 1235 | blk_finish_plug(&plug); |
a19be5f0 | 1236 | |
4d05a28d KRW |
1237 | if (operation == READ) |
1238 | blkif->st_rd_sect += preq.nr_sects; | |
5c62cb48 | 1239 | else if (operation & WRITE) |
4d05a28d KRW |
1240 | blkif->st_wr_sect += preq.nr_sects; |
1241 | ||
fc53bf75 | 1242 | return 0; |
4d05a28d KRW |
1243 | |
1244 | fail_flush: | |
9f3aedf5 | 1245 | xen_blkbk_unmap(pending_req); |
4d05a28d | 1246 | fail_response: |
0faa8cca | 1247 | /* Haven't submitted any bio's yet. */ |
97e36834 | 1248 | make_response(blkif, req->u.rw.id, req->operation, BLKIF_RSP_ERROR); |
4d05a28d KRW |
1249 | free_req(pending_req); |
1250 | msleep(1); /* back off a bit */ | |
fc53bf75 | 1251 | return -EIO; |
4d05a28d KRW |
1252 | |
1253 | fail_put_bio: | |
03e0edf9 | 1254 | for (i = 0; i < nbio; i++) |
77089926 | 1255 | bio_put(biolist[i]); |
0e5e098a | 1256 | atomic_set(&pending_req->pendcnt, 1); |
4d05a28d | 1257 | __end_block_io_op(pending_req, -EINVAL); |
4d05a28d | 1258 | msleep(1); /* back off a bit */ |
fc53bf75 | 1259 | return -EIO; |
4d05a28d KRW |
1260 | } |
1261 | ||
1262 | ||
1263 | ||
a1397fa3 KRW |
1264 | /* |
1265 | * Put a response on the ring on how the operation fared. | |
4d05a28d | 1266 | */ |
30fd1502 | 1267 | static void make_response(struct xen_blkif *blkif, u64 id, |
4d05a28d KRW |
1268 | unsigned short op, int st) |
1269 | { | |
88122933 | 1270 | struct blkif_response resp; |
4d05a28d | 1271 | unsigned long flags; |
88122933 | 1272 | union blkif_back_rings *blk_rings = &blkif->blk_rings; |
4d05a28d KRW |
1273 | int notify; |
1274 | ||
1275 | resp.id = id; | |
1276 | resp.operation = op; | |
1277 | resp.status = st; | |
1278 | ||
1279 | spin_lock_irqsave(&blkif->blk_ring_lock, flags); | |
1280 | /* Place on the response ring for the relevant domain. */ | |
1281 | switch (blkif->blk_protocol) { | |
1282 | case BLKIF_PROTOCOL_NATIVE: | |
1283 | memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt), | |
1284 | &resp, sizeof(resp)); | |
1285 | break; | |
1286 | case BLKIF_PROTOCOL_X86_32: | |
1287 | memcpy(RING_GET_RESPONSE(&blk_rings->x86_32, blk_rings->x86_32.rsp_prod_pvt), | |
1288 | &resp, sizeof(resp)); | |
1289 | break; | |
1290 | case BLKIF_PROTOCOL_X86_64: | |
1291 | memcpy(RING_GET_RESPONSE(&blk_rings->x86_64, blk_rings->x86_64.rsp_prod_pvt), | |
1292 | &resp, sizeof(resp)); | |
1293 | break; | |
1294 | default: | |
1295 | BUG(); | |
1296 | } | |
1297 | blk_rings->common.rsp_prod_pvt++; | |
1298 | RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify); | |
4d05a28d | 1299 | spin_unlock_irqrestore(&blkif->blk_ring_lock, flags); |
4d05a28d KRW |
1300 | if (notify) |
1301 | notify_remote_via_irq(blkif->irq); | |
1302 | } | |
1303 | ||
8b6bf747 | 1304 | static int __init xen_blkif_init(void) |
4d05a28d | 1305 | { |
bb6acb28 | 1306 | int i; |
8770b268 | 1307 | int rc = 0; |
4d05a28d | 1308 | |
b2167ba6 | 1309 | if (!xen_domain()) |
4d05a28d KRW |
1310 | return -ENODEV; |
1311 | ||
2e9977c2 | 1312 | blkbk = kzalloc(sizeof(struct xen_blkbk), GFP_KERNEL); |
e8e28871 | 1313 | if (!blkbk) { |
22b20f2d | 1314 | pr_alert(DRV_PFX "%s: out of memory!\n", __func__); |
e8e28871 KRW |
1315 | return -ENOMEM; |
1316 | } | |
1317 | ||
4d05a28d | 1318 | |
8e6dc6fe | 1319 | blkbk->pending_reqs = kzalloc(sizeof(blkbk->pending_reqs[0]) * |
8b6bf747 | 1320 | xen_blkif_reqs, GFP_KERNEL); |
4d05a28d | 1321 | |
bb6acb28 | 1322 | if (!blkbk->pending_reqs) { |
8770b268 | 1323 | rc = -ENOMEM; |
4d05a28d | 1324 | goto out_of_memory; |
8770b268 | 1325 | } |
4d05a28d | 1326 | |
8b6bf747 | 1327 | rc = xen_blkif_interface_init(); |
8770b268 KRW |
1328 | if (rc) |
1329 | goto failed_init; | |
4d05a28d | 1330 | |
e8e28871 KRW |
1331 | INIT_LIST_HEAD(&blkbk->pending_free); |
1332 | spin_lock_init(&blkbk->pending_free_lock); | |
1333 | init_waitqueue_head(&blkbk->pending_free_wq); | |
4d05a28d | 1334 | |
8b6bf747 | 1335 | for (i = 0; i < xen_blkif_reqs; i++) |
2e9977c2 KRW |
1336 | list_add_tail(&blkbk->pending_reqs[i].free_list, |
1337 | &blkbk->pending_free); | |
4d05a28d | 1338 | |
8b6bf747 | 1339 | rc = xen_blkif_xenbus_init(); |
8770b268 KRW |
1340 | if (rc) |
1341 | goto failed_init; | |
4d05a28d KRW |
1342 | |
1343 | return 0; | |
1344 | ||
1345 | out_of_memory: | |
22b20f2d | 1346 | pr_alert(DRV_PFX "%s: out of memory\n", __func__); |
8770b268 | 1347 | failed_init: |
e8e28871 | 1348 | kfree(blkbk->pending_reqs); |
a742b02c | 1349 | kfree(blkbk); |
e8e28871 | 1350 | blkbk = NULL; |
8770b268 | 1351 | return rc; |
4d05a28d KRW |
1352 | } |
1353 | ||
8b6bf747 | 1354 | module_init(xen_blkif_init); |
4d05a28d KRW |
1355 | |
1356 | MODULE_LICENSE("Dual BSD/GPL"); | |
a7e9357f | 1357 | MODULE_ALIAS("xen-backend:vbd"); |