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
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23 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
27 #ifndef __BLKIF__BACKEND__COMMON_H__
28 #define __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 */
66 struct blkif_x86_32_request {
67 uint8_t operation; /* BLKIF_OP_??? */
68 uint8_t nr_segments; /* number of segments */
69 blkif_vdev_t handle; /* only for read/write requests */
70 uint64_t id; /* private guest value, echoed in resp */
71 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
72 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
74 struct blkif_x86_32_response {
75 uint64_t id; /* copied from request */
76 uint8_t operation; /* copied from request */
77 int16_t status; /* BLKIF_RSP_??? */
79 typedef struct blkif_x86_32_request blkif_x86_32_request_t;
80 typedef struct blkif_x86_32_response blkif_x86_32_response_t;
83 /* x86_64 protocol version */
84 struct blkif_x86_64_request {
85 uint8_t operation; /* BLKIF_OP_??? */
86 uint8_t nr_segments; /* number of segments */
87 blkif_vdev_t handle; /* only for read/write requests */
88 uint64_t __attribute__((__aligned__(8))) id;
89 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
90 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
92 struct blkif_x86_64_response {
93 uint64_t __attribute__((__aligned__(8))) id;
94 uint8_t operation; /* copied from request */
95 int16_t status; /* BLKIF_RSP_??? */
97 typedef struct blkif_x86_64_request blkif_x86_64_request_t;
98 typedef struct blkif_x86_64_response blkif_x86_64_response_t;
100 DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
101 struct blkif_common_response);
102 DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
103 struct blkif_x86_32_response);
104 DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
105 struct blkif_x86_64_response);
107 union blkif_back_rings {
108 struct blkif_back_ring native;
109 struct blkif_common_back_ring common;
110 struct blkif_x86_32_back_ring x86_32;
111 struct blkif_x86_64_back_ring x86_64;
114 enum blkif_protocol {
115 BLKIF_PROTOCOL_NATIVE = 1,
116 BLKIF_PROTOCOL_X86_32 = 2,
117 BLKIF_PROTOCOL_X86_64 = 3,
121 /* What the domain refers to this vbd as. */
123 /* Non-zero -> read-only */
124 unsigned char readonly;
127 /* phys device that this vbd maps to. */
129 struct block_device *bdev;
130 /* Cached size parameter. */
138 /* Unique identifier for this interface. */
141 /* Physical parameters of the comms window. */
143 /* Comms information. */
144 enum blkif_protocol blk_protocol;
145 union blkif_back_rings blk_rings;
146 struct vm_struct *blk_ring_area;
147 /* The VBD attached to this interface. */
149 /* Back pointer to the backend_info. */
150 struct backend_info *be;
151 /* Private fields. */
152 spinlock_t blk_ring_lock;
155 wait_queue_head_t wq;
156 /* One thread per one blkif. */
157 struct task_struct *xenblkd;
158 unsigned int waiting_reqs;
161 unsigned long st_print;
169 wait_queue_head_t waiting_to_free;
171 grant_handle_t shmem_handle;
172 grant_ref_t shmem_ref;
176 #define vbd_sz(_v) ((_v)->bdev->bd_part ? \
177 (_v)->bdev->bd_part->nr_sects : \
178 get_capacity((_v)->bdev->bd_disk))
180 #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
181 #define xen_blkif_put(_b) \
183 if (atomic_dec_and_test(&(_b)->refcnt)) \
184 wake_up(&(_b)->waiting_to_free);\
189 unsigned short nr_sects;
190 struct block_device *bdev;
191 blkif_sector_t sector_number;
193 int xen_blkif_interface_init(void);
195 int xen_blkif_xenbus_init(void);
197 irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
198 int xen_blkif_schedule(void *arg);
200 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
201 struct backend_info *be, int state);
203 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
205 static inline void blkif_get_x86_32_req(struct blkif_request *dst,
206 struct blkif_x86_32_request *src)
208 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
209 dst->operation = src->operation;
210 dst->nr_segments = src->nr_segments;
211 dst->handle = src->handle;
213 dst->u.rw.sector_number = src->sector_number;
215 if (n > dst->nr_segments)
216 n = dst->nr_segments;
217 for (i = 0; i < n; i++)
218 dst->u.rw.seg[i] = src->seg[i];
221 static inline void blkif_get_x86_64_req(struct blkif_request *dst,
222 struct blkif_x86_64_request *src)
224 int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
225 dst->operation = src->operation;
226 dst->nr_segments = src->nr_segments;
227 dst->handle = src->handle;
229 dst->u.rw.sector_number = src->sector_number;
231 if (n > dst->nr_segments)
232 n = dst->nr_segments;
233 for (i = 0; i < n; i++)
234 dst->u.rw.seg[i] = src->seg[i];
237 #endif /* __BLKIF__BACKEND__COMMON_H__ */