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