include/linux/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  */
  21 enum 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  */
  31 struct 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
  40 static 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
  50 struct 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  */
  60 static inline u64 lower_48_bits(u64 n)
  61 {
  62         return n & ((1ull << 48) - 1);
  63 }
  64
  65 static 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