win-pvdrivers

view common/include/public/io/blkif.h @ 62:edd4a2ad5b44

Removed old inf files
author James Harper <james.harper@bendigoit.com.au>
date Wed Dec 19 10:22:50 2007 +1100 (2007-12-19)
parents 5712dede5a1b
children 71d971853d57
line source
1 /******************************************************************************
2 * blkif.h
3 *
4 * Unified block-device I/O interface for Xen guest OSes.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to
8 * deal in the Software without restriction, including without limitation the
9 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
10 * sell copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
22 * DEALINGS IN THE SOFTWARE.
23 *
24 * Copyright (c) 2003-2004, Keir Fraser
25 */
27 #ifndef __XEN_PUBLIC_IO_BLKIF_H__
28 #define __XEN_PUBLIC_IO_BLKIF_H__
30 #include "ring.h"
31 #include "../grant_table.h"
33 /*
34 * Front->back notifications: When enqueuing a new request, sending a
35 * notification can be made conditional on req_event (i.e., the generic
36 * hold-off mechanism provided by the ring macros). Backends must set
37 * req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
38 *
39 * Back->front notifications: When enqueuing a new response, sending a
40 * notification can be made conditional on rsp_event (i.e., the generic
41 * hold-off mechanism provided by the ring macros). Frontends must set
42 * rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
43 */
45 #ifndef blkif_vdev_t
46 #define blkif_vdev_t uint16_t
47 #endif
48 #define blkif_sector_t uint64_t
50 /*
51 * REQUEST CODES.
52 */
53 #define BLKIF_OP_READ 0
54 #define BLKIF_OP_WRITE 1
55 /*
56 * Recognised only if "feature-barrier" is present in backend xenbus info.
57 * The "feature_barrier" node contains a boolean indicating whether barrier
58 * requests are likely to succeed or fail. Either way, a barrier request
59 * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
60 * the underlying block-device hardware. The boolean simply indicates whether
61 * or not it is worthwhile for the frontend to attempt barrier requests.
62 * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not*
63 * create the "feature-barrier" node!
64 */
65 #define BLKIF_OP_WRITE_BARRIER 2
67 /*
68 * Maximum scatter/gather segments per request.
69 * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE.
70 * NB. This could be 12 if the ring indexes weren't stored in the same page.
71 */
72 #define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
74 struct blkif_request_segment {
75 grant_ref_t gref; /* reference to I/O buffer frame */
76 /* @first_sect: first sector in frame to transfer (inclusive). */
77 /* @last_sect: last sector in frame to transfer (inclusive). */
78 uint8_t first_sect, last_sect;
79 };
81 struct blkif_request {
82 uint8_t operation; /* BLKIF_OP_??? */
83 uint8_t nr_segments; /* number of segments */
84 blkif_vdev_t handle; /* only for read/write requests */
85 uint64_t id; /* private guest value, echoed in resp */
86 blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
87 struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
88 };
89 typedef struct blkif_request blkif_request_t;
91 struct blkif_response {
92 uint64_t id; /* copied from request */
93 uint8_t operation; /* copied from request */
94 int16_t status; /* BLKIF_RSP_??? */
95 };
96 typedef struct blkif_response blkif_response_t;
98 /*
99 * STATUS RETURN CODES.
100 */
101 /* Operation not supported (only happens on barrier writes). */
102 #define BLKIF_RSP_EOPNOTSUPP -2
103 /* Operation failed for some unspecified reason (-EIO). */
104 #define BLKIF_RSP_ERROR -1
105 /* Operation completed successfully. */
106 #define BLKIF_RSP_OKAY 0
108 /*
109 * Generate blkif ring structures and types.
110 */
112 DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
114 #define VDISK_CDROM 0x1
115 #define VDISK_REMOVABLE 0x2
116 #define VDISK_READONLY 0x4
118 #endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
120 /*
121 * Local variables:
122 * mode: C
123 * c-set-style: "BSD"
124 * c-basic-offset: 4
125 * tab-width: 4
126 * indent-tabs-mode: nil
127 * End:
128 */