include/linux/lz4.h: add some missing macros

Currently, LZ4_DISTANCE_MAX and LZ4_DECOMPRESS_INPLACE_MARGIN are
defined in the erofs subsystem for LZ4 in-place decompression, which is
somewhat unsuitable since they should belong to the LZ4 itself and
may change with future LZ4 codebase updates.

Move them to include/linux/lz4.h to match the upstream LZ4 library [1].
No logic changes.

[1] https://github.com/lz4/lz4/blob/v1.10.0/lib/lz4.h#L670

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Gao Xiang <[email protected]>
Cc: Yann Collet <[email protected]>
Cc: Nick Terrell <[email protected]>
Cc: Chao Yu <[email protected]>
Cc: Yue Hu <[email protected]>
Cc; Jeffle Xu <[email protected]>
Cc: Sandeep Dhavale <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

fs/erofs/decompressor.c

@@ -7,14 +7,7 @@
 #include "compress.h"
 #include <linux/lz4.h>
 
-#ifndef LZ4_DISTANCE_MAX	/* history window size */
-#define LZ4_DISTANCE_MAX 65535	/* set to maximum value by default */
-#endif
-
 #define LZ4_MAX_DISTANCE_PAGES	(DIV_ROUND_UP(LZ4_DISTANCE_MAX, PAGE_SIZE) + 1)
-#ifndef LZ4_DECOMPRESS_INPLACE_MARGIN
-#define LZ4_DECOMPRESS_INPLACE_MARGIN(srcsize)  (((srcsize) >> 8) + 32)
-#endif
 
 struct z_erofs_lz4_decompress_ctx {
 	struct z_erofs_decompress_req *rq;

include/linux/lz4.h

@@ -645,4 +645,10 @@ int LZ4_decompress_safe_usingDict(const char *source, char *dest,
 int LZ4_decompress_fast_usingDict(const char *source, char *dest,
 	int originalSize, const char *dictStart, int dictSize);
 
+#define LZ4_DECOMPRESS_INPLACE_MARGIN(compressedSize)          (((compressedSize) >> 8) + 32)
+
+#ifndef LZ4_DISTANCE_MAX	/* history window size; can be user-defined at compile time */
+#define LZ4_DISTANCE_MAX 65535	/* set to maximum value by default */
+#endif
+
 #endif

lib/lz4/lz4_compress.c

@@ -33,7 +33,6 @@
 /*-************************************
  *	Dependencies
  **************************************/
-#include <linux/lz4.h>
 #include "lz4defs.h"
 #include <linux/module.h>
 #include <linux/kernel.h>

lib/lz4/lz4_decompress.c

@@ -33,7 +33,6 @@
 /*-************************************
  *	Dependencies
  **************************************/
-#include <linux/lz4.h>
 #include "lz4defs.h"
 #include <linux/init.h>
 #include <linux/module.h>

lib/lz4/lz4defs.h

@@ -39,6 +39,7 @@
 
 #include <linux/bitops.h>
 #include <linux/string.h>	 /* memset, memcpy */
+#include <linux/lz4.h>
 
 #define FORCE_INLINE __always_inline
 
@@ -92,8 +93,7 @@ typedef uintptr_t uptrval;
 #define MB (1 << 20)
 #define GB (1U << 30)
 
-#define MAXD_LOG 16
-#define MAX_DISTANCE ((1 << MAXD_LOG) - 1)
+#define MAX_DISTANCE LZ4_DISTANCE_MAX
 #define STEPSIZE sizeof(size_t)
 
 #define ML_BITS	4

lib/lz4/lz4hc_compress.c

@@ -34,7 +34,6 @@
 /*-************************************
  *	Dependencies
  **************************************/
-#include <linux/lz4.h>
 #include "lz4defs.h"
 #include <linux/module.h>
 #include <linux/kernel.h>