#include "btrfs_drv.h"

Include dependency graph for galois.c:

Functions
void	galois_divpower (uint8_t *data, uint8_t div, uint32_t len)

uint8_t	gpow2 (uint8_t e)

uint8_t	gmul (uint8_t a, uint8_t b)

uint8_t	gdiv (uint8_t a, uint8_t b)

static __inline uint32_t	galois_double_mask32 (uint32_t v)

void	galois_double (uint8_t *data, uint32_t len)

Variables
static const uint8_t	glog []

static const uint8_t	gilog []

Function Documentation

◆ galois_divpower()

void galois_divpower	(	uint8_t *	data,
		uint8_t	div,
		uint32_t	len
	)

Definition at line 55 of file galois.c.

                                                               {
    while (len > 0) {
        if (data[0] != 0) {
            if (gilog[data[0]] <= div)
                data[0] = glog[(gilog[data[0]] + (255 - div)) % 255];
            else
                data[0] = glog[(gilog[data[0]] - div) % 255];
        }
 
        data++;
        len--;
    }
}

Referenced by raid6_recover2(), and scrub_raid6_stripe().

◆ galois_double()

void galois_double	(	uint8_t *	data,
		uint32_t	len
	)

Definition at line 109 of file galois.c.

                                                {
    // FIXME - SIMD?
 
#if defined(_AMD64_) || defined(_ARM64_)
    while (len > sizeof(uint64_t)) {
        uint64_t v = *((uint64_t*)data), vv;
 
        vv = (v << 1) & 0xfefefefefefefefe;
        vv ^= galois_double_mask64(v) & 0x1d1d1d1d1d1d1d1d;
        *((uint64_t*)data) = vv;
 
        data += sizeof(uint64_t);
        len -= sizeof(uint64_t);
    }
#else
    while (len > sizeof(uint32_t)) {
        uint32_t v = *((uint32_t*)data), vv;
 
        vv = (v << 1) & 0xfefefefe;
        vv ^= galois_double_mask32(v) & 0x1d1d1d1d;
        *((uint32_t*)data) = vv;
 
        data += sizeof(uint32_t);
        len -= sizeof(uint32_t);
    }
#endif
 
    while (len > 0) {
        data[0] = (data[0] << 1) ^ ((data[0] & 0x80) ? 0x1d : 0);
        data++;
        len--;
    }
}

Referenced by flush_partial_stripe(), raid6_recover2(), and scrub_raid6_stripe().

◆ galois_double_mask32()

static __inline uint32_t galois_double_mask32 ( uint32_t v )

static

Definition at line 103 of file galois.c.

                                                          {
    v &= 0x80808080;
    return (v << 1) - (v >> 7);
}

Referenced by galois_double().

◆ gdiv()

uint8_t gdiv	(	uint8_t	a,
		uint8_t	b
	)

Definition at line 80 of file galois.c.

                                   {
    if (b == 0) {
        return 0xff; // shouldn't happen
    } else if (a == 0) {
        return 0;
    } else {
        if (gilog[a] >= gilog[b])
            return glog[(gilog[a] - gilog[b]) % 255];
        else
            return glog[255-((gilog[b] - gilog[a]) % 255)];
    }
}

Referenced by raid6_recover2(), and scrub_raid6_stripe().

◆ gmul()

uint8_t gmul	(	uint8_t	a,
		uint8_t	b
	)

Definition at line 73 of file galois.c.

                                   {
    if (a == 0 || b == 0)
        return 0;
    else
        return glog[(gilog[a] + gilog[b]) % 255];
}

Referenced by raid6_recover2(), and scrub_raid6_stripe().

◆ gpow2()

uint8_t gpow2 ( uint8_t e )

Definition at line 69 of file galois.c.

                         {
    return glog[e%255];
}

Referenced by raid6_recover2(), and scrub_raid6_stripe().

Variable Documentation

◆ gilog

const uint8_t gilog[]

static

Initial value:

= {0x00, 0x00, 0x01, 0x19, 0x02, 0x32, 0x1a, 0xc6, 0x03, 0xdf, 0x33, 0xee, 0x1b, 0x68, 0xc7, 0x4b,
                              0x04, 0x64, 0xe0, 0x0e, 0x34, 0x8d, 0xef, 0x81, 0x1c, 0xc1, 0x69, 0xf8, 0xc8, 0x08, 0x4c, 0x71,
                              0x05, 0x8a, 0x65, 0x2f, 0xe1, 0x24, 0x0f, 0x21, 0x35, 0x93, 0x8e, 0xda, 0xf0, 0x12, 0x82, 0x45,
                              0x1d, 0xb5, 0xc2, 0x7d, 0x6a, 0x27, 0xf9, 0xb9, 0xc9, 0x9a, 0x09, 0x78, 0x4d, 0xe4, 0x72, 0xa6,
                              0x06, 0xbf, 0x8b, 0x62, 0x66, 0xdd, 0x30, 0xfd, 0xe2, 0x98, 0x25, 0xb3, 0x10, 0x91, 0x22, 0x88,
                              0x36, 0xd0, 0x94, 0xce, 0x8f, 0x96, 0xdb, 0xbd, 0xf1, 0xd2, 0x13, 0x5c, 0x83, 0x38, 0x46, 0x40,
                              0x1e, 0x42, 0xb6, 0xa3, 0xc3, 0x48, 0x7e, 0x6e, 0x6b, 0x3a, 0x28, 0x54, 0xfa, 0x85, 0xba, 0x3d,
                              0xca, 0x5e, 0x9b, 0x9f, 0x0a, 0x15, 0x79, 0x2b, 0x4e, 0xd4, 0xe5, 0xac, 0x73, 0xf3, 0xa7, 0x57,
                              0x07, 0x70, 0xc0, 0xf7, 0x8c, 0x80, 0x63, 0x0d, 0x67, 0x4a, 0xde, 0xed, 0x31, 0xc5, 0xfe, 0x18,
                              0xe3, 0xa5, 0x99, 0x77, 0x26, 0xb8, 0xb4, 0x7c, 0x11, 0x44, 0x92, 0xd9, 0x23, 0x20, 0x89, 0x2e,
                              0x37, 0x3f, 0xd1, 0x5b, 0x95, 0xbc, 0xcf, 0xcd, 0x90, 0x87, 0x97, 0xb2, 0xdc, 0xfc, 0xbe, 0x61,
                              0xf2, 0x56, 0xd3, 0xab, 0x14, 0x2a, 0x5d, 0x9e, 0x84, 0x3c, 0x39, 0x53, 0x47, 0x6d, 0x41, 0xa2,
                              0x1f, 0x2d, 0x43, 0xd8, 0xb7, 0x7b, 0xa4, 0x76, 0xc4, 0x17, 0x49, 0xec, 0x7f, 0x0c, 0x6f, 0xf6,
                              0x6c, 0xa1, 0x3b, 0x52, 0x29, 0x9d, 0x55, 0xaa, 0xfb, 0x60, 0x86, 0xb1, 0xbb, 0xcc, 0x3e, 0x5a,
                              0xcb, 0x59, 0x5f, 0xb0, 0x9c, 0xa9, 0xa0, 0x51, 0x0b, 0xf5, 0x16, 0xeb, 0x7a, 0x75, 0x2c, 0xd7,
                              0x4f, 0xae, 0xd5, 0xe9, 0xe6, 0xe7, 0xad, 0xe8, 0x74, 0xd6, 0xf4, 0xea, 0xa8, 0x50, 0x58, 0xaf}

Definition at line 37 of file galois.c.

Referenced by galois_divpower(), gdiv(), and gmul().

◆ glog

const uint8_t glog[]

static

Initial value:

= {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1d, 0x3a, 0x74, 0xe8, 0xcd, 0x87, 0x13, 0x26,
                             0x4c, 0x98, 0x2d, 0x5a, 0xb4, 0x75, 0xea, 0xc9, 0x8f, 0x03, 0x06, 0x0c, 0x18, 0x30, 0x60, 0xc0,
                             0x9d, 0x27, 0x4e, 0x9c, 0x25, 0x4a, 0x94, 0x35, 0x6a, 0xd4, 0xb5, 0x77, 0xee, 0xc1, 0x9f, 0x23,
                             0x46, 0x8c, 0x05, 0x0a, 0x14, 0x28, 0x50, 0xa0, 0x5d, 0xba, 0x69, 0xd2, 0xb9, 0x6f, 0xde, 0xa1,
                             0x5f, 0xbe, 0x61, 0xc2, 0x99, 0x2f, 0x5e, 0xbc, 0x65, 0xca, 0x89, 0x0f, 0x1e, 0x3c, 0x78, 0xf0,
                             0xfd, 0xe7, 0xd3, 0xbb, 0x6b, 0xd6, 0xb1, 0x7f, 0xfe, 0xe1, 0xdf, 0xa3, 0x5b, 0xb6, 0x71, 0xe2,
                             0xd9, 0xaf, 0x43, 0x86, 0x11, 0x22, 0x44, 0x88, 0x0d, 0x1a, 0x34, 0x68, 0xd0, 0xbd, 0x67, 0xce,
                             0x81, 0x1f, 0x3e, 0x7c, 0xf8, 0xed, 0xc7, 0x93, 0x3b, 0x76, 0xec, 0xc5, 0x97, 0x33, 0x66, 0xcc,
                             0x85, 0x17, 0x2e, 0x5c, 0xb8, 0x6d, 0xda, 0xa9, 0x4f, 0x9e, 0x21, 0x42, 0x84, 0x15, 0x2a, 0x54,
                             0xa8, 0x4d, 0x9a, 0x29, 0x52, 0xa4, 0x55, 0xaa, 0x49, 0x92, 0x39, 0x72, 0xe4, 0xd5, 0xb7, 0x73,
                             0xe6, 0xd1, 0xbf, 0x63, 0xc6, 0x91, 0x3f, 0x7e, 0xfc, 0xe5, 0xd7, 0xb3, 0x7b, 0xf6, 0xf1, 0xff,
                             0xe3, 0xdb, 0xab, 0x4b, 0x96, 0x31, 0x62, 0xc4, 0x95, 0x37, 0x6e, 0xdc, 0xa5, 0x57, 0xae, 0x41,
                             0x82, 0x19, 0x32, 0x64, 0xc8, 0x8d, 0x07, 0x0e, 0x1c, 0x38, 0x70, 0xe0, 0xdd, 0xa7, 0x53, 0xa6,
                             0x51, 0xa2, 0x59, 0xb2, 0x79, 0xf2, 0xf9, 0xef, 0xc3, 0x9b, 0x2b, 0x56, 0xac, 0x45, 0x8a, 0x09,
                             0x12, 0x24, 0x48, 0x90, 0x3d, 0x7a, 0xf4, 0xf5, 0xf7, 0xf3, 0xfb, 0xeb, 0xcb, 0x8b, 0x0b, 0x16,
                             0x2c, 0x58, 0xb0, 0x7d, 0xfa, 0xe9, 0xcf, 0x83, 0x1b, 0x36, 0x6c, 0xd8, 0xad, 0x47, 0x8e, 0x01}

Definition at line 20 of file galois.c.

Referenced by galois_divpower(), gdiv(), gmul(), and gpow2().

Functions

Variables

Function Documentation

◆ galois_divpower()

◆ galois_double()

◆ galois_double_mask32()

◆ gdiv()

◆ gmul()

◆ gpow2()

Variable Documentation

◆ gilog

◆ glog