Zstd: Update bundled library to version 1.5.7

Makefile.am

@@ -133,6 +133,7 @@ cstyle:
 		! -name 'zfs_config.*' ! -name '*.mod.c' \
 		! -name 'opt_global.h' ! -name '*_if*.h' \
 		! -name 'zstd_compat_wrapper.h' \
+		! -path './module/zstd/zstd-in.c' \
 		! -path './module/zstd/lib/*' \
 		! -path './include/sys/lua/*' \
 		! -path './module/lua/l*.[ch]' \

lib/libzstd/Makefile.am

@@ -26,10 +26,16 @@ nodist_libzstd_la_SOURCES = \
 	module/zstd/lib/compress/zstd_lazy.c \
 	module/zstd/lib/compress/zstd_ldm.c \
 	module/zstd/lib/compress/zstd_opt.c \
+	module/zstd/lib/compress/zstd_preSplit.c \
 	module/zstd/lib/decompress/huf_decompress.c \
 	module/zstd/lib/decompress/zstd_ddict.c \
 	module/zstd/lib/decompress/zstd_decompress.c \
 	module/zstd/lib/decompress/zstd_decompress_block.c \
 	module/zstd/zfs_zstd.c
 
+if TARGET_CPU_X86_64
+nodist_libzstd_la_SOURCES += \
+	module/zstd/lib/decompress/huf_decompress_amd64.S
+endif
+
 libzstd_la_CFLAGS += -include $(top_srcdir)/module/zstd/include/zstd_compat_wrapper.h -fno-tree-vectorize -Wp,-w $(AM_CFLAGS)

module/Kbuild.in

@@ -265,6 +265,15 @@ ZFS_ZSTD_FLAGS += -U__BMI__
 # Quiet warnings about frame size due to unused code in unmodified zstd lib
 ZFS_ZSTD_FLAGS += -Wframe-larger-than=20480
 
+# Disable assembly for kernel compatibility
+ZFS_ZSTD_FLAGS += -DZSTD_DISABLE_ASM
+
+# Disable intrinsics for EL10 x86_64-v3 baseline
+ZFS_ZSTD_FLAGS += -DZSTD_NO_INTRINSICS
+
+# Disable tracing for kernel builds
+ZFS_ZSTD_FLAGS += -DZSTD_TRACE=0
+
 ZSTD_OBJS := \
 	zfs_zstd.o \
 	zstd_sparc.o
@@ -287,6 +296,7 @@ ZSTD_UPSTREAM_OBJS := \
 	lib/compress/zstd_lazy.o \
 	lib/compress/zstd_ldm.o \
 	lib/compress/zstd_opt.o \
+	lib/compress/zstd_preSplit.o \
 	lib/decompress/huf_decompress.o \
 	lib/decompress/zstd_ddict.o \
 	lib/decompress/zstd_decompress.o \

module/Makefile.bsd

@@ -389,7 +389,6 @@ SRCS+=	entropy_common.c \
 	error_private.c \
 	fse_decompress.c \
 	pool.c \
-	xxhash.c \
 	zstd_common.c \
 
 #zstd/compress
@@ -404,7 +403,8 @@ SRCS+=	fse_compress.c \
 	zstd_fast.c \
 	zstd_lazy.c \
 	zstd_ldm.c \
-	zstd_opt.c
+	zstd_opt.c \
+	zstd_preSplit.c
 
 #zstd/decompress
 SRCS+=	huf_decompress.c \

module/zstd/README.md

@@ -1,11 +1,11 @@
-# ZSTD-On-ZFS Library Manual
+# Zstd-On-ZFS Library Manual
 
 ## Introduction
 
-This subtree contains the ZSTD library used in ZFS. It is heavily cut-down by
+This subtree contains the Zstd library used in ZFS. It is heavily cut-down by
 dropping any unneeded files, and combined into a single file, but otherwise is
 intentionally unmodified. Please do not alter the file containing the zstd
-library, besides upgrading to a newer ZSTD release.
+library, besides upgrading to a newer Zstd release.
 
 Tree structure:
 
@@ -14,25 +14,43 @@ Tree structure:
 * `zstd-in.c` is our template file for generating the single-file library
 * `include/`: This directory contains supplemental includes for platform
   compatibility, which are not expected to be used by ZFS elsewhere in the
-  future. Thus we keep them private to ZSTD.
+  future. Thus we keep them private to Zstd.
 
-## Updating ZSTD
+## Zstd update policy
 
-To update ZSTD the following steps need to be taken:
+Since the exact compressed byte stream may change between Zstd versions, updates
+should follow this policy:
 
-1. Grab the latest release of [ZSTD](https://github.com/facebook/zstd/releases).
+1. Zstd may be updated, as needed, after a new .0 release is tagged.
+2. Critical patches may be applied up until the next release freeze,
+   _potentially_ even updating to a newer upstream version.
+3. The Zstd version will not be upgraded within a major release.
+4. Multiple Zstd versions are not supported concurrently within a release.
+5. The library import commit must be a clean, unmodified upstream import. Any
+   OpenZFS-specific integration or local adjustments go into follow-up commits.
+6. Release notes should highlight Zstd updates and any expected impact (e.g.
+   changes in compression ratio/performance, and differences in compressed byte
+   streams which may affect deduplication or NOP writes).
+
+## Updating Zstd
+
+To update Zstd the following steps need to be taken:
+
+1. Grab the latest release of [Zstd](https://github.com/facebook/zstd/releases).
 2. Copy the files output by the following script to `module/zstd/lib/`:
-`grep include [path to zstd]/contrib/single_file_libs/zstd-in.c  | awk '{ print $2 }'`
+   ```
+   grep include [path to zstd]/build/single_file_libs/zstd-in.c | awk '{ print $2 }'
+   ```
 3. Remove debug.c, threading.c, and zstdmt_compress.c.
 4. Update Makefiles with resulting file lists.
-5. Follow symbol renaming notes in `include/zstd_compat_wrapper.h`
+5. Follow symbol renaming notes in `include/zstd_compat_wrapper.h`.
 
-## Altering ZSTD and breaking changes
+## Altering Zstd and breaking changes
 
-If ZSTD made changes that break compatibility or you need to make breaking
-changes to the way we handle ZSTD, it is required to maintain backwards
+If Zstd made changes that break compatibility or you need to make breaking
+changes to the way we handle Zstd, it is required to maintain backwards
 compatibility.
 
-We already save the ZSTD version number within the block header to be used
+We already save the Zstd version number within the block header to be used
 to add future compatibility checks and/or fixes. However, currently it is
 not actually used in such a way.