blob: b483d1909d3e6baee31be68e5e905aca4a15572c [file] [log] [blame]
/* This header will be used by application too */
#include <linux/types.h>
#include <linux/uio.h>
#define TCMU_VERSION "1.0"
* Ring Design
* -----------
* The mmaped area is divided into three parts:
* 1) The mailbox (struct tcmu_mailbox, below)
* 2) The command ring
* 3) Everything beyond the command ring (data)
* The mailbox tells userspace the offset of the command ring from the
* start of the shared memory region, and how big the command ring is.
* The kernel passes SCSI commands to userspace by putting a struct
* tcmu_cmd_entry in the ring, updating mailbox->cmd_head, and poking
* userspace via uio's interrupt mechanism.
* tcmu_cmd_entry contains a header. If the header type is PAD,
* userspace should skip hdr->length bytes (mod cmdr_size) to find the
* next cmd_entry.
* Otherwise, the entry will contain offsets into the mmaped area that
* contain the cdb and data buffers -- the latter accessible via the
* iov array. iov addresses are also offsets into the shared area.
* When userspace is completed handling the command, set
* entry->rsp.scsi_status, fill in rsp.sense_buffer if appropriate,
* and also set mailbox->cmd_tail equal to the old cmd_tail plus
* hdr->length, mod cmdr_size. If cmd_tail doesn't equal cmd_head, it
* should process the next packet the same way, and so on.
#define ALIGN_SIZE 64 /* Should be enough for most CPUs */
struct tcmu_mailbox {
__u16 version;
__u16 flags;
__u32 cmdr_off;
__u32 cmdr_size;
__u32 cmd_head;
/* Updated by user. On its own cacheline */
__u32 cmd_tail __attribute__((__aligned__(ALIGN_SIZE)));
} __packed;
enum tcmu_opcode {
* Only a few opcodes, and length is 8-byte aligned, so use low bits for opcode.
struct tcmu_cmd_entry_hdr {
__u32 len_op;
} __packed;
#define TCMU_OP_MASK 0x7
static inline enum tcmu_opcode tcmu_hdr_get_op(struct tcmu_cmd_entry_hdr *hdr)
return hdr->len_op & TCMU_OP_MASK;
static inline void tcmu_hdr_set_op(struct tcmu_cmd_entry_hdr *hdr, enum tcmu_opcode op)
hdr->len_op &= ~TCMU_OP_MASK;
hdr->len_op |= (op & TCMU_OP_MASK);
static inline __u32 tcmu_hdr_get_len(struct tcmu_cmd_entry_hdr *hdr)
return hdr->len_op & ~TCMU_OP_MASK;
static inline void tcmu_hdr_set_len(struct tcmu_cmd_entry_hdr *hdr, __u32 len)
hdr->len_op &= TCMU_OP_MASK;
hdr->len_op |= len;
/* Currently the same as SCSI_SENSE_BUFFERSIZE */
struct tcmu_cmd_entry {
struct tcmu_cmd_entry_hdr hdr;
uint16_t cmd_id;
uint16_t __pad1;
union {
struct {
uint64_t cdb_off;
uint64_t iov_cnt;
struct iovec iov[0];
} req;
struct {
uint8_t scsi_status;
uint8_t __pad1;
uint16_t __pad2;
uint32_t __pad3;
char sense_buffer[TCMU_SENSE_BUFFERSIZE];
} rsp;
} __packed;
#define TCMU_OP_ALIGN_SIZE sizeof(uint64_t)
enum tcmu_genl_cmd {
#define TCMU_CMD_MAX (__TCMU_CMD_MAX - 1)
enum tcmu_genl_attr {