md/raid6: move raid6 data processing to raid6_pq.ko

Move the raid6 data processing routines into a standalone module
(raid6_pq) to prepare them to be called from async_tx wrappers and other
non-md drivers/modules.  This precludes a circular dependency of raid456
needing the async modules for data processing while those modules in
turn depend on raid456 for the base level synchronous raid6 routines.

To support this move:
1/ The exportable definitions in raid6.h move to include/linux/raid/pq.h
2/ The raid6_call, recovery calls, and table symbols are exported
3/ Extra #ifdef __KERNEL__ statements to enable the userspace raid6test to
   compile

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 132 insertions, 0 deletions

diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
new file mode 100644
index 000000000000..d92480f8285c
--- /dev/null
+++ b/include/linux/raid/pq.h
@@ -0,0 +1,132 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright 2003 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef LINUX_RAID_RAID6_H
+#define LINUX_RAID_RAID6_H
+
+#ifdef __KERNEL__
+
+/* Set to 1 to use kernel-wide empty_zero_page */
+#define RAID6_USE_EMPTY_ZERO_PAGE 0
+#include <linux/blkdev.h>
+
+/* We need a pre-zeroed page... if we don't want to use the kernel-provided
+   one define it here */
+#if RAID6_USE_EMPTY_ZERO_PAGE
+# define raid6_empty_zero_page empty_zero_page
+#else
+extern const char raid6_empty_zero_page[PAGE_SIZE];
+#endif
+
+#else /* ! __KERNEL__ */
+/* Used for testing in user space */
+
+#include <errno.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stddef.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+
+/* Not standard, but glibc defines it */
+#define BITS_PER_LONG __WORDSIZE
+
+typedef uint8_t  u8;
+typedef uint16_t u16;
+typedef uint32_t u32;
+typedef uint64_t u64;
+
+#ifndef PAGE_SIZE
+# define PAGE_SIZE 4096
+#endif
+extern const char raid6_empty_zero_page[PAGE_SIZE];
+
+#define __init
+#define __exit
+#define __attribute_const__ __attribute__((const))
+#define noinline __attribute__((noinline))
+
+#define preempt_enable()
+#define preempt_disable()
+#define cpu_has_feature(x) 1
+#define enable_kernel_altivec()
+#define disable_kernel_altivec()
+
+#define EXPORT_SYMBOL(sym)
+#define MODULE_LICENSE(licence)
+#define subsys_initcall(x)
+#define module_exit(x)
+#endif /* __KERNEL__ */
+
+/* Routine choices */
+struct raid6_calls {
+        void (*gen_syndrome)(int, size_t, void **);
+        int  (*valid)(void);    /* Returns 1 if this routine set is usable */
+        const char *name;       /* Name of this routine set */
+        int prefer;             /* Has special performance attribute */
+};
+
+/* Selected algorithm */
+extern struct raid6_calls raid6_call;
+
+/* Algorithm list */
+extern const struct raid6_calls * const raid6_algos[];
+int raid6_select_algo(void);
+
+/* Return values from chk_syndrome */
+#define RAID6_OK        0
+#define RAID6_P_BAD     1
+#define RAID6_Q_BAD     2
+#define RAID6_PQ_BAD    3
+
+/* Galois field tables */
+extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256)));
+extern const u8 raid6_gfexp[256]      __attribute__((aligned(256)));
+extern const u8 raid6_gfinv[256]      __attribute__((aligned(256)));
+extern const u8 raid6_gfexi[256]      __attribute__((aligned(256)));
+
+/* Recovery routines */
+void raid6_2data_recov(int disks, size_t bytes, int faila, int failb,
+                       void **ptrs);
+void raid6_datap_recov(int disks, size_t bytes, int faila, void **ptrs);
+void raid6_dual_recov(int disks, size_t bytes, int faila, int failb,
+                      void **ptrs);
+
+/* Some definitions to allow code to be compiled for testing in userspace */
+#ifndef __KERNEL__
+
+# define jiffies        raid6_jiffies()
+# define printk         printf
+# define GFP_KERNEL     0
+# define __get_free_pages(x, y) ((unsigned long)mmap(NULL, PAGE_SIZE << (y), \
+                                                     PROT_READ|PROT_WRITE,   \
+                                                     MAP_PRIVATE|MAP_ANONYMOUS,\
+                                                     0, 0))
+# define free_pages(x, y)       munmap((void *)(x), (y)*PAGE_SIZE)
+
+static inline void cpu_relax(void)
+{
+        /* Nothing */
+}
+
+#undef  HZ
+#define HZ 1000
+static inline uint32_t raid6_jiffies(void)
+{
+        struct timeval tv;
+        gettimeofday(&tv, NULL);
+        return tv.tv_sec*1000 + tv.tv_usec/1000;
+}
+
+#endif /* ! __KERNEL__ */
+
+#endif /* LINUX_RAID_RAID6_H */