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 #include <linux/blkdev.h>
  21
  22 /* Additional compute_parity mode -- updates the parity w/o LOCKING */
  23 #define UPDATE_PARITY   4
  24
  25 /* We need a pre-zeroed page... if we don't want to use the kernel-provided
  26    one define it here */
  27 #if RAID6_USE_EMPTY_ZERO_PAGE
  28 # define raid6_empty_zero_page empty_zero_page
  29 #else
  30 extern const char raid6_empty_zero_page[PAGE_SIZE];
  31 #endif
  32
  33 #else /* ! __KERNEL__ */
  34 /* Used for testing in user space */
  35
  36 #include <errno.h>
  37 #include <inttypes.h>
  38 #include <limits.h>
  39 #include <stddef.h>
  40 #include <sys/mman.h>
  41 #include <sys/types.h>
  42
  43 /* Not standard, but glibc defines it */
  44 #define BITS_PER_LONG __WORDSIZE
  45
  46 typedef uint8_t  u8;
  47 typedef uint16_t u16;
  48 typedef uint32_t u32;
  49 typedef uint64_t u64;
  50
  51 #ifndef PAGE_SIZE
  52 # define PAGE_SIZE 4096
  53 #endif
  54 extern const char raid6_empty_zero_page[PAGE_SIZE];
  55
  56 #define __init
  57 #define __exit
  58 #define __attribute_const__ __attribute__((const))
  59 #define noinline __attribute__((noinline))
  60
  61 #define preempt_enable()
  62 #define preempt_disable()
  63 #define cpu_has_feature(x) 1
  64 #define enable_kernel_altivec()
  65 #define disable_kernel_altivec()
  66
  67 #endif /* __KERNEL__ */
  68
  69 /* Routine choices */
  70 struct raid6_calls {
  71         void (*gen_syndrome)(int, size_t, void **);
  72         int  (*valid)(void);    /* Returns 1 if this routine set is usable */
  73         const char *name;       /* Name of this routine set */
  74         int prefer;             /* Has special performance attribute */
  75 };
  76
  77 /* Selected algorithm */
  78 extern struct raid6_calls raid6_call;
  79
  80 /* Algorithm list */
  81 extern const struct raid6_calls * const raid6_algos[];
  82 int raid6_select_algo(void);
  83
  84 /* Return values from chk_syndrome */
  85 #define RAID6_OK        0
  86 #define RAID6_P_BAD     1
  87 #define RAID6_Q_BAD     2
  88 #define RAID6_PQ_BAD    3
  89
  90 /* Galois field tables */
  91 extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
  92 extern const u8 raid6_gfexp[256]      __attribute__((aligned(256)));
  93 extern const u8 raid6_gfinv[256]      __attribute__((aligned(256)));
  94 extern const u8 raid6_gfexi[256]      __attribute__((aligned(256)));
  95
  96 /* Recovery routines */
  97 void raid6_2data_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
  98 void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs);
  99 void raid6_dual_recov(int disks, size_t bytes, int faila, int failb, void **ptrs);
 100
 101 /* Some definitions to allow code to be compiled for testing in userspace */
 102 #ifndef __KERNEL__
 103
 104 # define jiffies        raid6_jiffies()
 105 # define printk         printf
 106 # define GFP_KERNEL     0
 107 # define __get_free_pages(x,y)  ((unsigned long)mmap(NULL, PAGE_SIZE << (y), PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0))
 108 # define free_pages(x,y)        munmap((void *)(x), (y)*PAGE_SIZE)
 109
 110 static inline void cpu_relax(void)
 111 {
 112         /* Nothing */
 113 }
 114
 115 #undef  HZ
 116 #define HZ 1000
 117 static inline uint32_t raid6_jiffies(void)
 118 {
 119         struct timeval tv;
 120         gettimeofday(&tv, NULL);
 121         return tv.tv_sec*1000 + tv.tv_usec/1000;
 122 }
 123
 124 #endif /* ! __KERNEL__ */
 125
 126 #endif /* LINUX_RAID_RAID6_H */