Linux 4.2.1
[linux/fpc-iii.git] / drivers / block / xen-blkback / common.h
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1 /*
2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License version 2
4 * as published by the Free Software Foundation; or, when distributed
5 * separately from the Linux kernel or incorporated into other
6 * software packages, subject to the following license:
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this source file (the "Software"), to deal in the Software without
10 * restriction, including without limitation the rights to use, copy, modify,
11 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
12 * and to permit persons to whom the Software is furnished to do so, subject to
13 * the following conditions:
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * IN THE SOFTWARE.
27 #ifndef __XEN_BLKIF__BACKEND__COMMON_H__
28 #define __XEN_BLKIF__BACKEND__COMMON_H__
30 #include <linux/module.h>
31 #include <linux/interrupt.h>
32 #include <linux/slab.h>
33 #include <linux/blkdev.h>
34 #include <linux/vmalloc.h>
35 #include <linux/wait.h>
36 #include <linux/io.h>
37 #include <linux/rbtree.h>
38 #include <asm/setup.h>
39 #include <asm/pgalloc.h>
40 #include <asm/hypervisor.h>
41 #include <xen/grant_table.h>
42 #include <xen/xenbus.h>
43 #include <xen/interface/io/ring.h>
44 #include <xen/interface/io/blkif.h>
45 #include <xen/interface/io/protocols.h>
47 extern unsigned int xen_blkif_max_ring_order;
49 * This is the maximum number of segments that would be allowed in indirect
50 * requests. This value will also be passed to the frontend.
52 #define MAX_INDIRECT_SEGMENTS 256
54 #define SEGS_PER_INDIRECT_FRAME \
55 (PAGE_SIZE/sizeof(struct blkif_request_segment))
56 #define MAX_INDIRECT_PAGES \
57 ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
58 #define INDIRECT_PAGES(_segs) \
59 ((_segs + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
61 /* Not a real protocol. Used to generate ring structs which contain
62 * the elements common to all protocols only. This way we get a
63 * compiler-checkable way to use common struct elements, so we can
64 * avoid using switch(protocol) in a number of places. */
65 struct blkif_common_request {
66 char dummy;
68 struct blkif_common_response {
69 char dummy;
72 struct blkif_x86_32_request_rw {
73 uint8_t nr_segments; /* number of segments */
74 blkif_vdev_t handle; /* only for read/write requests */
75 uint64_t id; /* private guest value, echoed in resp */
76 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
77 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
78 } __attribute__((__packed__));
80 struct blkif_x86_32_request_discard {
81 uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
82 blkif_vdev_t _pad1; /* was "handle" for read/write requests */
83 uint64_t id; /* private guest value, echoed in resp */
84 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
85 uint64_t nr_sectors;
86 } __attribute__((__packed__));
88 struct blkif_x86_32_request_other {
89 uint8_t _pad1;
90 blkif_vdev_t _pad2;
91 uint64_t id; /* private guest value, echoed in resp */
92 } __attribute__((__packed__));
94 struct blkif_x86_32_request_indirect {
95 uint8_t indirect_op;
96 uint16_t nr_segments;
97 uint64_t id;
98 blkif_sector_t sector_number;
99 blkif_vdev_t handle;
100 uint16_t _pad1;
101 grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
103 * The maximum number of indirect segments (and pages) that will
104 * be used is determined by MAX_INDIRECT_SEGMENTS, this value
105 * is also exported to the guest (via xenstore
106 * feature-max-indirect-segments entry), so the frontend knows how
107 * many indirect segments the backend supports.
109 uint64_t _pad2; /* make it 64 byte aligned */
110 } __attribute__((__packed__));
112 struct blkif_x86_32_request {
113 uint8_t operation; /* BLKIF_OP_??? */
114 union {
115 struct blkif_x86_32_request_rw rw;
116 struct blkif_x86_32_request_discard discard;
117 struct blkif_x86_32_request_other other;
118 struct blkif_x86_32_request_indirect indirect;
119 } u;
120 } __attribute__((__packed__));
122 /* i386 protocol version */
123 #pragma pack(push, 4)
124 struct blkif_x86_32_response {
125 uint64_t id; /* copied from request */
126 uint8_t operation; /* copied from request */
127 int16_t status; /* BLKIF_RSP_??? */
129 #pragma pack(pop)
130 /* x86_64 protocol version */
132 struct blkif_x86_64_request_rw {
133 uint8_t nr_segments; /* number of segments */
134 blkif_vdev_t handle; /* only for read/write requests */
135 uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */
136 uint64_t id;
137 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
138 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
139 } __attribute__((__packed__));
141 struct blkif_x86_64_request_discard {
142 uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
143 blkif_vdev_t _pad1; /* was "handle" for read/write requests */
144 uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
145 uint64_t id;
146 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
147 uint64_t nr_sectors;
148 } __attribute__((__packed__));
150 struct blkif_x86_64_request_other {
151 uint8_t _pad1;
152 blkif_vdev_t _pad2;
153 uint32_t _pad3; /* offsetof(blkif_..,u.discard.id)==8 */
154 uint64_t id; /* private guest value, echoed in resp */
155 } __attribute__((__packed__));
157 struct blkif_x86_64_request_indirect {
158 uint8_t indirect_op;
159 uint16_t nr_segments;
160 uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */
161 uint64_t id;
162 blkif_sector_t sector_number;
163 blkif_vdev_t handle;
164 uint16_t _pad2;
165 grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
167 * The maximum number of indirect segments (and pages) that will
168 * be used is determined by MAX_INDIRECT_SEGMENTS, this value
169 * is also exported to the guest (via xenstore
170 * feature-max-indirect-segments entry), so the frontend knows how
171 * many indirect segments the backend supports.
173 uint32_t _pad3; /* make it 64 byte aligned */
174 } __attribute__((__packed__));
176 struct blkif_x86_64_request {
177 uint8_t operation; /* BLKIF_OP_??? */
178 union {
179 struct blkif_x86_64_request_rw rw;
180 struct blkif_x86_64_request_discard discard;
181 struct blkif_x86_64_request_other other;
182 struct blkif_x86_64_request_indirect indirect;
183 } u;
184 } __attribute__((__packed__));
186 struct blkif_x86_64_response {
187 uint64_t __attribute__((__aligned__(8))) id;
188 uint8_t operation; /* copied from request */
189 int16_t status; /* BLKIF_RSP_??? */
192 DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
193 struct blkif_common_response);
194 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
195 struct blkif_x86_32_response);
196 DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
197 struct blkif_x86_64_response);
199 union blkif_back_rings {
200 struct blkif_back_ring native;
201 struct blkif_common_back_ring common;
202 struct blkif_x86_32_back_ring x86_32;
203 struct blkif_x86_64_back_ring x86_64;
206 enum blkif_protocol {
207 BLKIF_PROTOCOL_NATIVE = 1,
208 BLKIF_PROTOCOL_X86_32 = 2,
209 BLKIF_PROTOCOL_X86_64 = 3,
213 * Default protocol if the frontend doesn't specify one.
215 #ifdef CONFIG_X86
216 # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_X86_32
217 #else
218 # define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_NATIVE
219 #endif
221 struct xen_vbd {
222 /* What the domain refers to this vbd as. */
223 blkif_vdev_t handle;
224 /* Non-zero -> read-only */
225 unsigned char readonly;
226 /* VDISK_xxx */
227 unsigned char type;
228 /* phys device that this vbd maps to. */
229 u32 pdevice;
230 struct block_device *bdev;
231 /* Cached size parameter. */
232 sector_t size;
233 unsigned int flush_support:1;
234 unsigned int discard_secure:1;
235 unsigned int feature_gnt_persistent:1;
236 unsigned int overflow_max_grants:1;
239 struct backend_info;
241 /* Number of available flags */
242 #define PERSISTENT_GNT_FLAGS_SIZE 2
243 /* This persistent grant is currently in use */
244 #define PERSISTENT_GNT_ACTIVE 0
246 * This persistent grant has been used, this flag is set when we remove the
247 * PERSISTENT_GNT_ACTIVE, to know that this grant has been used recently.
249 #define PERSISTENT_GNT_WAS_ACTIVE 1
251 /* Number of requests that we can fit in a ring */
252 #define XEN_BLKIF_REQS_PER_PAGE 32
254 struct persistent_gnt {
255 struct page *page;
256 grant_ref_t gnt;
257 grant_handle_t handle;
258 DECLARE_BITMAP(flags, PERSISTENT_GNT_FLAGS_SIZE);
259 struct rb_node node;
260 struct list_head remove_node;
263 struct xen_blkif {
264 /* Unique identifier for this interface. */
265 domid_t domid;
266 unsigned int handle;
267 /* Physical parameters of the comms window. */
268 unsigned int irq;
269 /* Comms information. */
270 enum blkif_protocol blk_protocol;
271 union blkif_back_rings blk_rings;
272 void *blk_ring;
273 /* The VBD attached to this interface. */
274 struct xen_vbd vbd;
275 /* Back pointer to the backend_info. */
276 struct backend_info *be;
277 /* Private fields. */
278 spinlock_t blk_ring_lock;
279 atomic_t refcnt;
281 wait_queue_head_t wq;
282 /* for barrier (drain) requests */
283 struct completion drain_complete;
284 atomic_t drain;
285 atomic_t inflight;
286 /* One thread per one blkif. */
287 struct task_struct *xenblkd;
288 unsigned int waiting_reqs;
290 /* tree to store persistent grants */
291 struct rb_root persistent_gnts;
292 unsigned int persistent_gnt_c;
293 atomic_t persistent_gnt_in_use;
294 unsigned long next_lru;
296 /* used by the kworker that offload work from the persistent purge */
297 struct list_head persistent_purge_list;
298 struct work_struct persistent_purge_work;
300 /* buffer of free pages to map grant refs */
301 spinlock_t free_pages_lock;
302 int free_pages_num;
303 struct list_head free_pages;
305 /* List of all 'pending_req' available */
306 struct list_head pending_free;
307 /* And its spinlock. */
308 spinlock_t pending_free_lock;
309 wait_queue_head_t pending_free_wq;
311 /* statistics */
312 unsigned long st_print;
313 unsigned long long st_rd_req;
314 unsigned long long st_wr_req;
315 unsigned long long st_oo_req;
316 unsigned long long st_f_req;
317 unsigned long long st_ds_req;
318 unsigned long long st_rd_sect;
319 unsigned long long st_wr_sect;
321 struct work_struct free_work;
322 /* Thread shutdown wait queue. */
323 wait_queue_head_t shutdown_wq;
324 unsigned int nr_ring_pages;
327 struct seg_buf {
328 unsigned long offset;
329 unsigned int nsec;
332 struct grant_page {
333 struct page *page;
334 struct persistent_gnt *persistent_gnt;
335 grant_handle_t handle;
336 grant_ref_t gref;
340 * Each outstanding request that we've passed to the lower device layers has a
341 * 'pending_req' allocated to it. Each buffer_head that completes decrements
342 * the pendcnt towards zero. When it hits zero, the specified domain has a
343 * response queued for it, with the saved 'id' passed back.
345 struct pending_req {
346 struct xen_blkif *blkif;
347 u64 id;
348 int nr_segs;
349 atomic_t pendcnt;
350 unsigned short operation;
351 int status;
352 struct list_head free_list;
353 struct grant_page *segments[MAX_INDIRECT_SEGMENTS];
354 /* Indirect descriptors */
355 struct grant_page *indirect_pages[MAX_INDIRECT_PAGES];
356 struct seg_buf seg[MAX_INDIRECT_SEGMENTS];
357 struct bio *biolist[MAX_INDIRECT_SEGMENTS];
358 struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS];
359 struct page *unmap_pages[MAX_INDIRECT_SEGMENTS];
360 struct gntab_unmap_queue_data gnttab_unmap_data;
364 #define vbd_sz(_v) ((_v)->bdev->bd_part ? \
365 (_v)->bdev->bd_part->nr_sects : \
366 get_capacity((_v)->bdev->bd_disk))
368 #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
369 #define xen_blkif_put(_b) \
370 do { \
371 if (atomic_dec_and_test(&(_b)->refcnt)) \
372 schedule_work(&(_b)->free_work);\
373 } while (0)
375 struct phys_req {
376 unsigned short dev;
377 blkif_sector_t nr_sects;
378 struct block_device *bdev;
379 blkif_sector_t sector_number;
381 int xen_blkif_interface_init(void);
383 int xen_blkif_xenbus_init(void);
385 irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
386 int xen_blkif_schedule(void *arg);
387 int xen_blkif_purge_persistent(void *arg);
388 void xen_blkbk_free_caches(struct xen_blkif *blkif);
390 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
391 struct backend_info *be, int state);
393 int xen_blkbk_barrier(struct xenbus_transaction xbt,
394 struct backend_info *be, int state);
395 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
396 void xen_blkbk_unmap_purged_grants(struct work_struct *work);
398 static inline void blkif_get_x86_32_req(struct blkif_request *dst,
399 struct blkif_x86_32_request *src)
401 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
402 dst->operation = src->operation;
403 switch (src->operation) {
404 case BLKIF_OP_READ:
405 case BLKIF_OP_WRITE:
406 case BLKIF_OP_WRITE_BARRIER:
407 case BLKIF_OP_FLUSH_DISKCACHE:
408 dst->u.rw.nr_segments = src->u.rw.nr_segments;
409 dst->u.rw.handle = src->u.rw.handle;
410 dst->u.rw.id = src->u.rw.id;
411 dst->u.rw.sector_number = src->u.rw.sector_number;
412 barrier();
413 if (n > dst->u.rw.nr_segments)
414 n = dst->u.rw.nr_segments;
415 for (i = 0; i < n; i++)
416 dst->u.rw.seg[i] = src->u.rw.seg[i];
417 break;
418 case BLKIF_OP_DISCARD:
419 dst->u.discard.flag = src->u.discard.flag;
420 dst->u.discard.id = src->u.discard.id;
421 dst->u.discard.sector_number = src->u.discard.sector_number;
422 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
423 break;
424 case BLKIF_OP_INDIRECT:
425 dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
426 dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
427 dst->u.indirect.handle = src->u.indirect.handle;
428 dst->u.indirect.id = src->u.indirect.id;
429 dst->u.indirect.sector_number = src->u.indirect.sector_number;
430 barrier();
431 j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
432 for (i = 0; i < j; i++)
433 dst->u.indirect.indirect_grefs[i] =
434 src->u.indirect.indirect_grefs[i];
435 break;
436 default:
438 * Don't know how to translate this op. Only get the
439 * ID so failure can be reported to the frontend.
441 dst->u.other.id = src->u.other.id;
442 break;
446 static inline void blkif_get_x86_64_req(struct blkif_request *dst,
447 struct blkif_x86_64_request *src)
449 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
450 dst->operation = src->operation;
451 switch (src->operation) {
452 case BLKIF_OP_READ:
453 case BLKIF_OP_WRITE:
454 case BLKIF_OP_WRITE_BARRIER:
455 case BLKIF_OP_FLUSH_DISKCACHE:
456 dst->u.rw.nr_segments = src->u.rw.nr_segments;
457 dst->u.rw.handle = src->u.rw.handle;
458 dst->u.rw.id = src->u.rw.id;
459 dst->u.rw.sector_number = src->u.rw.sector_number;
460 barrier();
461 if (n > dst->u.rw.nr_segments)
462 n = dst->u.rw.nr_segments;
463 for (i = 0; i < n; i++)
464 dst->u.rw.seg[i] = src->u.rw.seg[i];
465 break;
466 case BLKIF_OP_DISCARD:
467 dst->u.discard.flag = src->u.discard.flag;
468 dst->u.discard.id = src->u.discard.id;
469 dst->u.discard.sector_number = src->u.discard.sector_number;
470 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
471 break;
472 case BLKIF_OP_INDIRECT:
473 dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
474 dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
475 dst->u.indirect.handle = src->u.indirect.handle;
476 dst->u.indirect.id = src->u.indirect.id;
477 dst->u.indirect.sector_number = src->u.indirect.sector_number;
478 barrier();
479 j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
480 for (i = 0; i < j; i++)
481 dst->u.indirect.indirect_grefs[i] =
482 src->u.indirect.indirect_grefs[i];
483 break;
484 default:
486 * Don't know how to translate this op. Only get the
487 * ID so failure can be reported to the frontend.
489 dst->u.other.id = src->u.other.id;
490 break;
494 #endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */