From 9a5ce91d053961b7cc8fa56bd083819a9fc92734 Mon Sep 17 00:00:00 2001 From: Markus Stockhausen Date: Mon, 15 Dec 2014 12:57:04 +1100 Subject: [PATCH] md/raid6 algorithms: xor_syndrome() for generic int Start the algorithms with the very basic one. It is left and right optimized. That means we can avoid all calculations for unneeded pages above the right stop offset. For pages below the left start offset we still need the syndrome multiplication but without reading data pages. Signed-off-by: Markus Stockhausen Signed-off-by: NeilBrown --- lib/raid6/int.uc | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/lib/raid6/int.uc b/lib/raid6/int.uc index 5ca60bee1388..558aeac9342a 100644 --- a/lib/raid6/int.uc +++ b/lib/raid6/int.uc @@ -107,9 +107,47 @@ static void raid6_int$#_gen_syndrome(int disks, size_t bytes, void **ptrs) } } +static void raid6_int$#_xor_syndrome(int disks, int start, int stop, + size_t bytes, void **ptrs) +{ + u8 **dptr = (u8 **)ptrs; + u8 *p, *q; + int d, z, z0; + + unative_t wd$$, wq$$, wp$$, w1$$, w2$$; + + z0 = stop; /* P/Q right side optimization */ + p = dptr[disks-2]; /* XOR parity */ + q = dptr[disks-1]; /* RS syndrome */ + + for ( d = 0 ; d < bytes ; d += NSIZE*$# ) { + /* P/Q data pages */ + wq$$ = wp$$ = *(unative_t *)&dptr[z0][d+$$*NSIZE]; + for ( z = z0-1 ; z >= start ; z-- ) { + wd$$ = *(unative_t *)&dptr[z][d+$$*NSIZE]; + wp$$ ^= wd$$; + w2$$ = MASK(wq$$); + w1$$ = SHLBYTE(wq$$); + w2$$ &= NBYTES(0x1d); + w1$$ ^= w2$$; + wq$$ = w1$$ ^ wd$$; + } + /* P/Q left side optimization */ + for ( z = start-1 ; z >= 0 ; z-- ) { + w2$$ = MASK(wq$$); + w1$$ = SHLBYTE(wq$$); + w2$$ &= NBYTES(0x1d); + wq$$ = w1$$ ^ w2$$; + } + *(unative_t *)&p[d+NSIZE*$$] ^= wp$$; + *(unative_t *)&q[d+NSIZE*$$] ^= wq$$; + } + +} + const struct raid6_calls raid6_intx$# = { raid6_int$#_gen_syndrome, - NULL, /* XOR not yet implemented */ + raid6_int$#_xor_syndrome, NULL, /* always valid */ "int" NSTRING "x$#", 0