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5 * separately from the Linux kernel or incorporated into other
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27 #ifndef __XEN_BLKIF__BACKEND__COMMON_H__
28 #define __XEN_BLKIF__BACKEND__COMMON_H__
30 #include <linux/version.h>
31 #include <linux/module.h>
32 #include <linux/interrupt.h>
33 #include <linux/slab.h>
34 #include <linux/blkdev.h>
35 #include <linux/vmalloc.h>
36 #include <linux/wait.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 #define DRV_PFX "xen-blkback:"
48 #define DPRINTK(fmt, args...) \
49 pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \
50 __func__, __LINE__, ##args)
53 /* Not a real protocol. Used to generate ring structs which contain
54 * the elements common to all protocols only. This way we get a
55 * compiler-checkable way to use common struct elements, so we can
56 * avoid using switch(protocol) in a number of places. */
57 struct blkif_common_request {
60 struct blkif_common_response {
64 /* i386 protocol version */
67 struct blkif_x86_32_request_rw {
68 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
69 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
72 struct blkif_x86_32_request_discard {
73 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
77 struct blkif_x86_32_request {
78 uint8_t operation; /* BLKIF_OP_??? */
79 uint8_t nr_segments; /* number of segments */
80 blkif_vdev_t handle; /* only for read/write requests */
81 uint64_t id; /* private guest value, echoed in resp */
83 struct blkif_x86_32_request_rw rw;
84 struct blkif_x86_32_request_discard discard;
87 struct blkif_x86_32_response {
88 uint64_t id; /* copied from request */
89 uint8_t operation; /* copied from request */
90 int16_t status; /* BLKIF_RSP_??? */
94 /* x86_64 protocol version */
96 struct blkif_x86_64_request_rw {
97 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
98 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
101 struct blkif_x86_64_request_discard {
102 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
106 struct blkif_x86_64_request {
107 uint8_t operation; /* BLKIF_OP_??? */
108 uint8_t nr_segments; /* number of segments */
109 blkif_vdev_t handle; /* only for read/write requests */
110 uint64_t __attribute__((__aligned__(8))) id;
112 struct blkif_x86_64_request_rw rw;
113 struct blkif_x86_64_request_discard discard;
116 struct blkif_x86_64_response {
117 uint64_t __attribute__((__aligned__(8))) id;
118 uint8_t operation; /* copied from request */
119 int16_t status; /* BLKIF_RSP_??? */
122 DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
123 struct blkif_common_response);
124 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
125 struct blkif_x86_32_response);
126 DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
127 struct blkif_x86_64_response);
129 union blkif_back_rings {
130 struct blkif_back_ring native;
131 struct blkif_common_back_ring common;
132 struct blkif_x86_32_back_ring x86_32;
133 struct blkif_x86_64_back_ring x86_64;
136 enum blkif_protocol {
137 BLKIF_PROTOCOL_NATIVE = 1,
138 BLKIF_PROTOCOL_X86_32 = 2,
139 BLKIF_PROTOCOL_X86_64 = 3,
142 enum blkif_backend_type {
143 BLKIF_BACKEND_PHY = 1,
144 BLKIF_BACKEND_FILE = 2,
148 /* What the domain refers to this vbd as. */
150 /* Non-zero -> read-only */
151 unsigned char readonly;
154 /* phys device that this vbd maps to. */
156 struct block_device *bdev;
157 /* Cached size parameter. */
165 /* Unique identifier for this interface. */
168 /* Physical parameters of the comms window. */
170 /* Comms information. */
171 enum blkif_protocol blk_protocol;
172 enum blkif_backend_type blk_backend_type;
173 union blkif_back_rings blk_rings;
174 struct vm_struct *blk_ring_area;
175 /* The VBD attached to this interface. */
177 /* Back pointer to the backend_info. */
178 struct backend_info *be;
179 /* Private fields. */
180 spinlock_t blk_ring_lock;
183 wait_queue_head_t wq;
184 /* for barrier (drain) requests */
185 struct completion drain_complete;
187 /* One thread per one blkif. */
188 struct task_struct *xenblkd;
189 unsigned int waiting_reqs;
192 unsigned long st_print;
201 wait_queue_head_t waiting_to_free;
203 grant_handle_t shmem_handle;
204 grant_ref_t shmem_ref;
208 #define vbd_sz(_v) ((_v)->bdev->bd_part ? \
209 (_v)->bdev->bd_part->nr_sects : \
210 get_capacity((_v)->bdev->bd_disk))
212 #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
213 #define xen_blkif_put(_b) \
215 if (atomic_dec_and_test(&(_b)->refcnt)) \
216 wake_up(&(_b)->waiting_to_free);\
221 blkif_sector_t nr_sects;
222 struct block_device *bdev;
223 blkif_sector_t sector_number;
225 int xen_blkif_interface_init(void);
227 int xen_blkif_xenbus_init(void);
229 irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
230 int xen_blkif_schedule(void *arg);
232 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
233 struct backend_info *be, int state);
235 int xen_blkbk_barrier(struct xenbus_transaction xbt,
236 struct backend_info *be, int state);
237 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
239 static inline void blkif_get_x86_32_req(struct blkif_request *dst,
240 struct blkif_x86_32_request *src)
242 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
243 dst->operation = src->operation;
244 dst->nr_segments = src->nr_segments;
245 dst->handle = src->handle;
247 switch (src->operation) {
250 case BLKIF_OP_WRITE_BARRIER:
251 case BLKIF_OP_FLUSH_DISKCACHE:
252 dst->u.rw.sector_number = src->u.rw.sector_number;
254 if (n > dst->nr_segments)
255 n = dst->nr_segments;
256 for (i = 0; i < n; i++)
257 dst->u.rw.seg[i] = src->u.rw.seg[i];
259 case BLKIF_OP_DISCARD:
260 dst->u.discard.sector_number = src->u.discard.sector_number;
261 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
268 static inline void blkif_get_x86_64_req(struct blkif_request *dst,
269 struct blkif_x86_64_request *src)
271 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
272 dst->operation = src->operation;
273 dst->nr_segments = src->nr_segments;
274 dst->handle = src->handle;
276 switch (src->operation) {
279 case BLKIF_OP_WRITE_BARRIER:
280 case BLKIF_OP_FLUSH_DISKCACHE:
281 dst->u.rw.sector_number = src->u.rw.sector_number;
283 if (n > dst->nr_segments)
284 n = dst->nr_segments;
285 for (i = 0; i < n; i++)
286 dst->u.rw.seg[i] = src->u.rw.seg[i];
288 case BLKIF_OP_DISCARD:
289 dst->u.discard.sector_number = src->u.discard.sector_number;
290 dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
297 #endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */