t10-pi.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _LINUX_T10_PI_H
 3#define _LINUX_T10_PI_H
 4
 5#include <linux/types.h>
 6#include <linux/blk-mq.h>
 7
 8/*
 9 * A T10 PI-capable target device can be formatted with different
10 * protection schemes.	Currently 0 through 3 are defined:
11 *
12 * Type 0 is regular (unprotected) I/O
13 *
14 * Type 1 defines the contents of the guard and reference tags
15 *
16 * Type 2 defines the contents of the guard and reference tags and
17 * uses 32-byte commands to seed the latter
18 *
19 * Type 3 defines the contents of the guard tag only
20 */
21enum t10_dif_type {
22	T10_PI_TYPE0_PROTECTION = 0x0,
23	T10_PI_TYPE1_PROTECTION = 0x1,
24	T10_PI_TYPE2_PROTECTION = 0x2,
25	T10_PI_TYPE3_PROTECTION = 0x3,
26};
27
28/*
29 * T10 Protection Information tuple.
30 */
31struct t10_pi_tuple {
32	__be16 guard_tag;	/* Checksum */
33	__be16 app_tag;		/* Opaque storage */
34	__be32 ref_tag;		/* Target LBA or indirect LBA */
35};
36
37#define T10_PI_APP_ESCAPE cpu_to_be16(0xffff)
38#define T10_PI_REF_ESCAPE cpu_to_be32(0xffffffff)
39
40static inline u32 t10_pi_ref_tag(struct request *rq)
41{
42	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
43
44	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
45	    rq->q->limits.integrity.interval_exp)
46		shift = rq->q->limits.integrity.interval_exp;
47	return blk_rq_pos(rq) >> (shift - SECTOR_SHIFT) & 0xffffffff;
48}
49
50struct crc64_pi_tuple {
51	__be64 guard_tag;
52	__be16 app_tag;
53	__u8   ref_tag[6];
54};
55
56/**
57 * lower_48_bits() - return bits 0-47 of a number
58 * @n: the number we're accessing
59 */
60static inline u64 lower_48_bits(u64 n)
61{
62	return n & ((1ull << 48) - 1);
63}
64
65static inline u64 ext_pi_ref_tag(struct request *rq)
66{
67	unsigned int shift = ilog2(queue_logical_block_size(rq->q));
68
69	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY) &&
70	    rq->q->limits.integrity.interval_exp)
71		shift = rq->q->limits.integrity.interval_exp;
72	return lower_48_bits(blk_rq_pos(rq) >> (shift - SECTOR_SHIFT));
73}
74
75#endif