commit c7afa4b260ab9b22950620ea5aa1f5abbb984519
Author: Markus Stockhausen <markus.stockhausen@xxxxxxxxxxx>
Date: Sun Aug 10 09:33:18 2014 +0000
raid6 algorithms: delta syndrome dummy functions
Implementing rmw functionality for RAID6 requires optimized syndrome
calculation. Up to now we can only generate a complete syndrome. The
target P/Q pages are always overwritten. With this patch we provide
a framework for inplace P/Q modification. Although a lot of coding
was added it follows a simple rule: Duplicate existing gen_syndrome()
functions to (still empty) xor_syndrome() ones.
xor_syndrome() has two additional parameters: start & stop. These
will indicate the first and last page that are changing during a
rmw run. That makes it possible to avoid several unneccessary loops
and speed up calculation. The caller needs to implement the following
logic to make the functions work.
1) xor_syndrome(disks, start, stop, ...): "Remove" all data of source
blocks inside P/Q between (and including) start and end.
2) modify any block with start <= block <= stop
3) xor_syndrome(disks, start, stop, ...): "Reinsert" all data of
source blocks into P/Q between (and including) start and end.
Additionally relax the setting of /sys/block/mdX/md/rmw_level to
allow rmw enabling if the choosen algorithm offers xor_syndrome().
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ba32c1f..c1a0dfe 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5393,8 +5393,8 @@ raid5_store_rmw_level(struct mddev *mddev, const char *page, size_t len)
new != PARITY_PREFER_RMW)
return -EINVAL;
- /* RAID6 does not support rmw yet */
- if (new != PARITY_DISABLE_RMW && conf->level == 6)
+ /* RAID6 supports rmw depending on algorithm */
+ if (new != PARITY_DISABLE_RMW && conf->level == 6 && !raid6_call.hasxor)
return -EINVAL;
conf->rmw_level = new;
diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h
index 73069cb..0384980 100644
--- a/include/linux/raid/pq.h
+++ b/include/linux/raid/pq.h
@@ -72,9 +72,11 @@ extern const char raid6_empty_zero_page[PAGE_SIZE];
/* Routine choices */
struct raid6_calls {
void (*gen_syndrome)(int, size_t, void **);
+ void (*xor_syndrome)(int, int, 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 */
+ int hasxor; /* Has additional XOR method */
};
/* Selected algorithm */
diff --git a/lib/raid6/altivec.uc b/lib/raid6/altivec.uc
index 7cc12b5..bdad7de 100644
--- a/lib/raid6/altivec.uc
+++ b/lib/raid6/altivec.uc
@@ -104,6 +104,24 @@ static void raid6_altivec$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
preempt_enable();
}
+static void noinline
+raid6_altivec$#_gen_syndrome_real(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
+static void raid6_altivec$#_xor_syndrome(int disks, int start, int stop,
+ tsize_t bytes, void **ptrs)
+{
+ preempt_disable();
+ enable_kernel_altivec();
+
+ raid6_altivec$#_xor_syndrome_real(disks, start, stop, bytes, ptrs);
+
+ preempt_enable();
+}
+
int raid6_have_altivec(void);
#if $# == 1
int raid6_have_altivec(void)
@@ -119,9 +137,11 @@ int raid6_have_altivec(void)
const struct raid6_calls raid6_altivec$# = {
raid6_altivec$#_gen_syndrome,
+ raid6_altivec$#_xor_syndrome,
raid6_have_altivec,
"altivecx$#",
- 0
+ 0,
+ 0, /* XOR not yet implemented */
};
#endif /* CONFIG_ALTIVEC */
diff --git a/lib/raid6/avx2.c b/lib/raid6/avx2.c
index bc3b1dd..225ca38 100644
--- a/lib/raid6/avx2.c
+++ b/lib/raid6/avx2.c
@@ -87,11 +87,19 @@ static void raid6_avx21_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_avx21_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_avx2x1 = {
raid6_avx21_gen_syndrome,
+ raid6_avx21_xor_syndrome,
raid6_have_avx2,
"avx2x1",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
/*
@@ -148,11 +156,19 @@ static void raid6_avx22_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_avx22_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_avx2x2 = {
raid6_avx22_gen_syndrome,
+ raid6_avx22_xor_syndrome,
raid6_have_avx2,
"avx2x2",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
#ifdef CONFIG_X86_64
@@ -240,11 +256,19 @@ static void raid6_avx24_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_avx24_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_avx2x4 = {
raid6_avx24_gen_syndrome,
+ raid6_avx24_xor_syndrome,
raid6_have_avx2,
"avx2x4",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
#endif
diff --git a/lib/raid6/int.uc b/lib/raid6/int.uc
index 5b50f8d..283a9a3 100644
--- a/lib/raid6/int.uc
+++ b/lib/raid6/int.uc
@@ -107,11 +107,19 @@ static void raid6_int$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
}
}
+static void raid6_int$#_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_intx$# = {
raid6_int$#_gen_syndrome,
- NULL, /* always valid */
+ raid6_int$#_xor_syndrome,
+ NULL, /* always valid */
"int" NSTRING "x$#",
- 0
+ 0,
+ 0 /* XOR not yet implemented */
};
#endif
diff --git a/lib/raid6/mmx.c b/lib/raid6/mmx.c
index 590c71c..6ed27c7 100644
--- a/lib/raid6/mmx.c
+++ b/lib/raid6/mmx.c
@@ -74,11 +74,19 @@ static void raid6_mmx1_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_mmx1_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_mmxx1 = {
raid6_mmx1_gen_syndrome,
+ raid6_mmx1_xor_syndrome,
raid6_have_mmx,
"mmxx1",
- 0
+ 0,
+ 0 /* XOR not yet implemented */
};
/*
@@ -132,11 +140,19 @@ static void raid6_mmx2_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_mmx2_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_mmxx2 = {
raid6_mmx2_gen_syndrome,
+ raid6_mmx2_xor_syndrome,
raid6_have_mmx,
"mmxx2",
- 0
+ 0,
+ 0 /* XOR not yet implemented */
};
#endif
diff --git a/lib/raid6/neon.c b/lib/raid6/neon.c
index 36ad470..a0af518 100644
--- a/lib/raid6/neon.c
+++ b/lib/raid6/neon.c
@@ -40,11 +40,26 @@
(unsigned long)bytes, ptrs); \
kernel_neon_end(); \
} \
+ static void raid6_neon ## _n ## _xor_syndrome(int disks, \
+ int start, int stop, \
+ size_t bytes, void **ptrs) \
+ { \
+ void raid6_neon ## _n ## _xor_syndrome_real(int, \
+ int, int, \
+ unsigned long, void**); \
+ kernel_neon_begin(); \
+ raid6_neon ## _n ## _xor_syndrome_real(disks, \
+ start, stop, \
+ (unsigned long)bytes, ptrs); \
+ kernel_neon_end(); \
+ } \
struct raid6_calls const raid6_neonx ## _n = { \
raid6_neon ## _n ## _gen_syndrome, \
+ raid6_neon ## _n ## _xor_syndrome, \
raid6_have_neon, \
"neonx" #_n, \
- 0 \
+ 0, \
+ 0 /* XOR not yet implemented */ \
}
static int raid6_have_neon(void)
diff --git a/lib/raid6/neon.uc b/lib/raid6/neon.uc
index 1b9ed79..c5e30f0 100644
--- a/lib/raid6/neon.uc
+++ b/lib/raid6/neon.uc
@@ -78,3 +78,9 @@ void raid6_neon$#_gen_syndrome_real(int disks, unsigned long bytes, void **ptrs)
vst1q_u8(&q[d+NSIZE*$$], wq$$);
}
}
+
+void raid6_neon$#_xor_syndrome_real(int disks, int start, int stop,
+ unsigned long bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
diff --git a/lib/raid6/sse1.c b/lib/raid6/sse1.c
index f762971..5a43c87 100644
--- a/lib/raid6/sse1.c
+++ b/lib/raid6/sse1.c
@@ -90,11 +90,19 @@ static void raid6_sse11_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_sse11_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_sse1x1 = {
raid6_sse11_gen_syndrome,
+ raid6_sse11_xor_syndrome,
raid6_have_sse1_or_mmxext,
"sse1x1",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
/*
@@ -152,11 +160,20 @@ static void raid6_sse12_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_sse12_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
+
const struct raid6_calls raid6_sse1x2 = {
raid6_sse12_gen_syndrome,
+ raid6_sse12_xor_syndrome,
raid6_have_sse1_or_mmxext,
"sse1x2",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
#endif
diff --git a/lib/raid6/sse2.c b/lib/raid6/sse2.c
index 85b82c8..7ec2b6e 100644
--- a/lib/raid6/sse2.c
+++ b/lib/raid6/sse2.c
@@ -88,11 +88,19 @@ static void raid6_sse21_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_sse21_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_sse2x1 = {
raid6_sse21_gen_syndrome,
+ raid6_sse21_xor_syndrome,
raid6_have_sse2,
"sse2x1",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
/*
@@ -150,11 +158,20 @@ static void raid6_sse22_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_sse22_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
+
const struct raid6_calls raid6_sse2x2 = {
raid6_sse22_gen_syndrome,
+ raid6_sse22_xor_syndrome,
raid6_have_sse2,
"sse2x2",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
#ifdef CONFIG_X86_64
@@ -248,11 +265,20 @@ static void raid6_sse24_gen_syndrome(int disks, size_t bytes, void **ptrs)
kernel_fpu_end();
}
+static void raid6_sse24_xor_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
+
const struct raid6_calls raid6_sse2x4 = {
raid6_sse24_gen_syndrome,
+ raid6_sse24_xor_syndrome,
raid6_have_sse2,
"sse2x4",
- 1 /* Has cache hints */
+ 1, /* Has cache hints */
+ 0 /* XOR not yet implemented */
};
#endif /* CONFIG_X86_64 */
diff --git a/lib/raid6/tilegx.uc b/lib/raid6/tilegx.uc
index e7c2945..ce619c1 100644
--- a/lib/raid6/tilegx.uc
+++ b/lib/raid6/tilegx.uc
@@ -78,9 +78,17 @@ void raid6_tilegx$#_gen_syndrome(int disks, size_t bytes, void **ptrs)
}
}
+void raid6_tilegx$#_gen_syndrome(int disks, int start, int stop,
+ size_t bytes, void **ptrs)
+{
+ /* enable hasxor if implemented */
+}
+
const struct raid6_calls raid6_tilegx$# = {
raid6_tilegx$#_gen_syndrome,
+ raid6_tilegx$#_xor_syndrome,
NULL,
"tilegx$#",
- 0
+ 0,
+ 0 /* XOR not yet implemented */
};
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