Linux kernel mirror (for testing)
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linux
1#ifndef __TARGET_CORE_USER_H
2#define __TARGET_CORE_USER_H
3
4/* This header will be used by application too */
5
6#include <linux/types.h>
7#include <linux/uio.h>
8
9#ifndef __packed
10#define __packed __attribute__((packed))
11#endif
12
13#define TCMU_VERSION "1.0"
14
15/*
16 * Ring Design
17 * -----------
18 *
19 * The mmaped area is divided into three parts:
20 * 1) The mailbox (struct tcmu_mailbox, below)
21 * 2) The command ring
22 * 3) Everything beyond the command ring (data)
23 *
24 * The mailbox tells userspace the offset of the command ring from the
25 * start of the shared memory region, and how big the command ring is.
26 *
27 * The kernel passes SCSI commands to userspace by putting a struct
28 * tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
29 * userspace via uio's interrupt mechanism.
30 *
31 * tcmu_cmd_entry contains a header. If the header type is PAD,
32 * userspace should skip hdr->length bytes (mod cmdr_size) to find the
33 * next cmd_entry.
34 *
35 * Otherwise, the entry will contain offsets into the mmaped area that
36 * contain the cdb and data buffers -- the latter accessible via the
37 * iov array. iov addresses are also offsets into the shared area.
38 *
39 * When userspace is completed handling the command, set
40 * entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
41 * and also set mailbox->cmd_tail equal to the old cmd_tail plus
42 * hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
43 * should process the next packet the same way, and so on.
44 */
45
46#define TCMU_MAILBOX_VERSION 1
47#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
48
49struct tcmu_mailbox {
50 __u16 version;
51 __u16 flags;
52 __u32 cmdr_off;
53 __u32 cmdr_size;
54
55 __u32 cmd_head;
56
57 /* Updated by user. On its own cacheline */
58 __u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
59
60} __packed;
61
62enum tcmu_opcode {
63 TCMU_OP_PAD = 0,
64 TCMU_OP_CMD,
65};
66
67/*
68 * Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
69 */
70struct tcmu_cmd_entry_hdr {
71 __u32 len_op;
72} __packed;
73
74#define TCMU_OP_MASK 0x7
75
76static inline enum tcmu_opcode tcmu_hdr_get_op(struct tcmu_cmd_entry_hdr *hdr)
77{
78 return hdr->len_op & TCMU_OP_MASK;
79}
80
81static inline void tcmu_hdr_set_op(struct tcmu_cmd_entry_hdr *hdr, enum tcmu_opcode op)
82{
83 hdr->len_op &= ~TCMU_OP_MASK;
84 hdr->len_op |= (op & TCMU_OP_MASK);
85}
86
87static inline __u32 tcmu_hdr_get_len(struct tcmu_cmd_entry_hdr *hdr)
88{
89 return hdr->len_op & ~TCMU_OP_MASK;
90}
91
92static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len)
93{
94 hdr->len_op &= TCMU_OP_MASK;
95 hdr->len_op |= len;
96}
97
98/* Currently the same as SCSI_SENSE_BUFFERSIZE */
99#define TCMU_SENSE_BUFFERSIZE 96
100
101struct tcmu_cmd_entry {
102 struct tcmu_cmd_entry_hdr hdr;
103
104 uint16_t cmd_id;
105 uint16_t __pad1;
106
107 union {
108 struct {
109 uint64_t cdb_off;
110 uint64_t iov_cnt;
111 struct iovec iov[0];
112 } req;
113 struct {
114 uint8_t scsi_status;
115 uint8_t __pad1;
116 uint16_t __pad2;
117 uint32_t __pad3;
118 char sense_buffer[TCMU_SENSE_BUFFERSIZE];
119 } rsp;
120 };
121
122} __packed;
123
124#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
125
126enum tcmu_genl_cmd {
127 TCMU_CMD_UNSPEC,
128 TCMU_CMD_ADDED_DEVICE,
129 TCMU_CMD_REMOVED_DEVICE,
130 __TCMU_CMD_MAX,
131};
132#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
133
134enum tcmu_genl_attr {
135 TCMU_ATTR_UNSPEC,
136 TCMU_ATTR_DEVICE,
137 TCMU_ATTR_MINOR,
138 __TCMU_ATTR_MAX,
139};
140#define TCMU_ATTR_MAX (__TCMU_ATTR_MAX - 1)
141
142#endif