drivers/md/raid6.h

   1 /* -*- linux-c -*- ------------------------------------------------------- *
   2  *
   3  *   Copyright 2003 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Bostom MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 #ifndef LINUX_RAID_RAID6_H
  14 #define LINUX_RAID_RAID6_H
  15
  16 #ifdef __KERNEL__
  17
  18 /* Set to 1 to use kernel-wide empty_zero_page */
  19 #define RAID6_USE_EMPTY_ZERO_PAGE 0
  20
  21 #include <linux/module.h>
  22 #include <linux/stddef.h>
  23 #include <linux/compiler.h>
  24 #include <linux/types.h>
  25 #include <linux/kernel.h>
  26 #include <linux/errno.h>
  27 #include <linux/mempool.h>
  28 #include <linux/list.h>
  29 #include <linux/vmalloc.h>
  30 #include <linux/raid/md.h>
  31 #include <linux/raid/raid5.h>
  32
  33 typedef raid5_conf_t raid6_conf_t; /* Same configuration */
  34
  35 /* Additional compute_parity mode -- updates the parity w/o LOCKING */
  36 #define UPDATE_PARITY   4
  37
  38 /* We need a pre-zeroed page... if we don't want to use the kernel-provided
  39    one define it here */
  40 #if RAID6_USE_EMPTY_ZERO_PAGE
  41 # define raid6_empty_zero_page empty_zero_page
  42 #else
  43 extern const char raid6_empty_zero_page[PAGE_SIZE];
  44 #endif
  45
  46 #else /* ! __KERNEL__ */
  47 /* Used for testing in user space */
  48
  49 #include <errno.h>
  50 #include <inttypes.h>
  51 #include <limits.h>
  52 #include <stddef.h>
  53 #include <sys/mman.h>
  54 #include <sys/types.h>
  55
  56 /* Not standard, but glibc defines it */
  57 #define BITS_PER_LONG __WORDSIZE
  58
  59 typedef uint8_t  u8;
  60 typedef uint16_t u16;
  61 typedef uint32_t u32;
  62 typedef uint64_t u64;
  63
  64 #ifndef PAGE_SIZE
  65 # define PAGE_SIZE 4096
  66 #endif
  67 extern const char raid6_empty_zero_page[PAGE_SIZE];
  68
  69 #define __init
  70 #define __exit
  71 #define __attribute_const__ __attribute__((const))
  72
  73 #define preempt_enable()
  74 #define preempt_disable()
  75
  76 #endif /* __KERNEL__ */
  77
  78 /* Routine choices */
  79 struct raid6_calls {
  80         void (*gen_syndrome)(int, size_t, void **);
  81         int  (*valid)(void);    /* Returns 1 if this routine set is usable */
  82         const char *name;       /* Name of this routine set */
  83         int prefer;             /* Has special performance attribute */
  84 };
  85
  86 /* Selected algorithm */
  87 extern struct raid6_calls raid6_call;
  88
  89 /* Algorithm list */
  90 extern const struct raid6_calls * const raid6_algos[];
  91 int raid6_select_algo(void);
  92
  93 /* Return values from chk_syndrome */
  94 #define RAID6_OK        0
  95 #define RAID6_P_BAD     1
  96 #define RAID6_Q_BAD     2
  97 #define RAID6_PQ_BAD    3
  98
  99 /* Galois field tables */
 100 extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
 101 extern const u8 raid6_gfexp[256]      __attribute__((aligned(256)));
 102 extern const u8 raid6_gfinv[256]      __attribute__((aligned(256)));
 103 extern const u8 raid6_gfexi[256]      __attribute__((aligned(256)));
 104
 105 /* Recovery routines */
 106 void raid6_2data_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
 107 void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs);
 108 void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
 109
 110 /* Some definitions to allow code to be compiled for testing in userspace */
 111 #ifndef __KERNEL__
 112
 113 # define jiffies        raid6_jiffies()
 114 # define printk         printf
 115 # define GFP_KERNEL     0
 116 # define __get_free_pages(x,y)  ((unsigned long)mmap(NULL, PAGE_SIZE << (y), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0))
 117 # define free_pages(x,y)        munmap((void *)(x), (y)*PAGE_SIZE)
 118
 119 static inline void cpu_relax(void)
 120 {
 121         /* Nothing */
 122 }
 123
 124 #undef  HZ
 125 #define HZ 1000
 126 static inline uint32_t raid6_jiffies(void)
 127 {
 128         struct timeval tv;
 129         gettimeofday(&tv, NULL);
 130         return tv.tv_sec*1000 + tv.tv_usec/1000;
 131 }
 132
 133 #endif /* ! __KERNEL__ */
 134
 135 #endif /* LINUX_RAID_RAID6_H */