Use fletcher_4 routines natively with `abd_iterate_func()`

This patch adds the necessary infrastructure for ABD to make use
of the vectorized fletcher 4 routines.

- export ABD compatible interface from fletcher_4
- add ABD fletcher_4 tests for data and metadata ABD types.

Reviewed-by: Brian Behlendorf <[email protected]>
Original-patch-by: Gvozden Neskovic <[email protected]>
Signed-off-by: David Quigley <[email protected]>
Closes #5589 

2 files changed, 112 insertions, 8 deletions

diff --git a/module/zcommon/zfs_fletcher.c b/module/zcommon/zfs_fletcher.c
index 1d1ea2e24..9cdf36d44 100644
--- a/module/zcommon/zfs_fletcher.c
+++ b/module/zcommon/zfs_fletcher.c
@@ -141,6 +141,7 @@
 #include <sys/zfs_context.h>
 #include <zfs_fletcher.h>
 
+#define	FLETCHER_MIN_SIMD_SIZE	64
 
 static void fletcher_4_scalar_init(fletcher_4_ctx_t *ctx);
 static void fletcher_4_scalar_fini(fletcher_4_ctx_t *ctx, zio_cksum_t *zcp);
@@ -456,7 +457,7 @@ void
 fletcher_4_native(const void *buf, uint64_t size,
     const void *ctx_template, zio_cksum_t *zcp)
 {
-	const uint64_t p2size = P2ALIGN(size, 64);
+	const uint64_t p2size = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE);
 
 	ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t)));
 
@@ -498,7 +499,7 @@ void
 fletcher_4_byteswap(const void *buf, uint64_t size,
     const void *ctx_template, zio_cksum_t *zcp)
 {
-	const uint64_t p2size = P2ALIGN(size, 64);
+	const uint64_t p2size = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE);
 
 	ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t)));
 
@@ -778,6 +779,87 @@ fletcher_4_fini(void)
 	}
 }
 
+/* ABD adapters */
+
+static void
+abd_fletcher_4_init(zio_abd_checksum_data_t *cdp)
+{
+	const fletcher_4_ops_t *ops = fletcher_4_impl_get();
+	cdp->acd_private = (void *) ops;
+
+	if (cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE)
+		ops->init_native(cdp->acd_ctx);
+	else
+		ops->init_byteswap(cdp->acd_ctx);
+}
+
+static void
+abd_fletcher_4_fini(zio_abd_checksum_data_t *cdp)
+{
+	fletcher_4_ops_t *ops = (fletcher_4_ops_t *)cdp->acd_private;
+
+	ASSERT(ops);
+
+	if (cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE)
+		ops->fini_native(cdp->acd_ctx, cdp->acd_zcp);
+	else
+		ops->fini_byteswap(cdp->acd_ctx, cdp->acd_zcp);
+}
+
+static void
+abd_fletcher_4_simd2scalar(boolean_t native, void *data, size_t size,
+    zio_abd_checksum_data_t *cdp)
+{
+	zio_cksum_t *zcp = cdp->acd_zcp;
+
+	ASSERT3U(size, <, FLETCHER_MIN_SIMD_SIZE);
+
+	abd_fletcher_4_fini(cdp);
+	cdp->acd_private = (void *)&fletcher_4_scalar_ops;
+
+	if (native)
+		fletcher_4_incremental_native(data, size, zcp);
+	else
+		fletcher_4_incremental_byteswap(data, size, zcp);
+}
+
+static int
+abd_fletcher_4_iter(void *data, size_t size, void *private)
+{
+	zio_abd_checksum_data_t *cdp = (zio_abd_checksum_data_t *)private;
+	fletcher_4_ctx_t *ctx = cdp->acd_ctx;
+	fletcher_4_ops_t *ops = (fletcher_4_ops_t *)cdp->acd_private;
+	boolean_t native = cdp->acd_byteorder == ZIO_CHECKSUM_NATIVE;
+	uint64_t asize = P2ALIGN(size, FLETCHER_MIN_SIMD_SIZE);
+
+	ASSERT(IS_P2ALIGNED(size, sizeof (uint32_t)));
+
+	if (asize > 0) {
+		if (native)
+			ops->compute_native(ctx, data, asize);
+		else
+			ops->compute_byteswap(ctx, data, asize);
+
+		size -= asize;
+		data = (char *)data + asize;
+	}
+
+	if (size > 0) {
+		ASSERT3U(size, <, FLETCHER_MIN_SIMD_SIZE);
+		/* At this point we have to switch to scalar impl */
+		abd_fletcher_4_simd2scalar(native, data, size, cdp);
+	}
+
+	return (0);
+}
+
+zio_abd_checksum_func_t fletcher_4_abd_ops = {
+	.acf_init = abd_fletcher_4_init,
+	.acf_fini = abd_fletcher_4_fini,
+	.acf_iter = abd_fletcher_4_iter
+};
+
+
 #if defined(_KERNEL) && defined(HAVE_SPL)
 #include <linux/mod_compat.h>
 
@@ -829,4 +911,5 @@ EXPORT_SYMBOL(fletcher_4_native_varsize);
 EXPORT_SYMBOL(fletcher_4_byteswap);
 EXPORT_SYMBOL(fletcher_4_incremental_native);
 EXPORT_SYMBOL(fletcher_4_incremental_byteswap);
+EXPORT_SYMBOL(fletcher_4_abd_ops);
 #endif
diff --git a/module/zfs/zio_checksum.c b/module/zfs/zio_checksum.c
index e65b3f061..703d9a5e5 100644
--- a/module/zfs/zio_checksum.c
+++ b/module/zfs/zio_checksum.c
@@ -119,14 +119,29 @@ abd_fletcher_2_byteswap(abd_t *abd, uint64_t size,
 	    fletcher_2_incremental_byteswap, zcp);
 }
 
+static inline void
+abd_fletcher_4_impl(abd_t *abd, uint64_t size, zio_abd_checksum_data_t *acdp)
+{
+	fletcher_4_abd_ops.acf_init(acdp);
+	abd_iterate_func(abd, 0, size, fletcher_4_abd_ops.acf_iter, acdp);
+	fletcher_4_abd_ops.acf_fini(acdp);
+}
+
 /*ARGSUSED*/
 void
 abd_fletcher_4_native(abd_t *abd, uint64_t size,
     const void *ctx_template, zio_cksum_t *zcp)
 {
-	fletcher_init(zcp);
-	(void) abd_iterate_func(abd, 0, size,
-	    fletcher_4_incremental_native, zcp);
+	fletcher_4_ctx_t ctx;
+
+	zio_abd_checksum_data_t acd = {
+		.acd_byteorder	= ZIO_CHECKSUM_NATIVE,
+		.acd_zcp 	= zcp,
+		.acd_ctx	= &ctx
+	};
+
+	abd_fletcher_4_impl(abd, size, &acd);
+
 }
 
 /*ARGSUSED*/
@@ -134,9 +149,15 @@ void
 abd_fletcher_4_byteswap(abd_t *abd, uint64_t size,
     const void *ctx_template, zio_cksum_t *zcp)
 {
-	fletcher_init(zcp);
-	(void) abd_iterate_func(abd, 0, size,
-	    fletcher_4_incremental_byteswap, zcp);
+	fletcher_4_ctx_t ctx;
+
+	zio_abd_checksum_data_t acd = {
+		.acd_byteorder	= ZIO_CHECKSUM_BYTESWAP,
+		.acd_zcp 	= zcp,
+		.acd_ctx	= &ctx
+	};
+
+	abd_fletcher_4_impl(abd, size, &acd);
 }
 
 zio_checksum_info_t zio_checksum_table[ZIO_CHECKSUM_FUNCTIONS] = {