Merge tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux

Pull CRC cleanups from Eric Biggers:
 "Simplify the kconfig options for controlling which CRC implementations
  are built into the kernel, as was requested by Linus.

  This means making the option to disable the arch code visible only
  when CONFIG_EXPERT=y, and standardizing on a single generic
  implementation of CRC32"

* tag 'crc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux:
  lib/crc32: remove other generic implementations
  lib/crc: simplify the kconfig options for CRC implementations

1 files changed, 30 insertions, 83 deletions

diff --git a/lib/gen_crc32table.c b/lib/gen_crc32table.c
index f755b997b967..6d03425b849e 100644
--- a/lib/gen_crc32table.c
+++ b/lib/gen_crc32table.c
@@ -2,30 +2,11 @@
 #include <stdio.h>
 #include "../include/linux/crc32poly.h"
 #include "../include/generated/autoconf.h"
-#include "crc32defs.h"
 #include <inttypes.h>
 
-#define ENTRIES_PER_LINE 4
-
-#if CRC_LE_BITS > 8
-# define LE_TABLE_ROWS (CRC_LE_BITS/8)
-# define LE_TABLE_SIZE 256
-#else
-# define LE_TABLE_ROWS 1
-# define LE_TABLE_SIZE (1 << CRC_LE_BITS)
-#endif
-
-#if CRC_BE_BITS > 8
-# define BE_TABLE_ROWS (CRC_BE_BITS/8)
-# define BE_TABLE_SIZE 256
-#else
-# define BE_TABLE_ROWS 1
-# define BE_TABLE_SIZE (1 << CRC_BE_BITS)
-#endif
-
-static uint32_t crc32table_le[LE_TABLE_ROWS][256];
-static uint32_t crc32table_be[BE_TABLE_ROWS][256];
-static uint32_t crc32ctable_le[LE_TABLE_ROWS][256];
+static uint32_t crc32table_le[256];
+static uint32_t crc32table_be[256];
+static uint32_t crc32ctable_le[256];
 
 /**
  * crc32init_le() - allocate and initialize LE table data
@@ -34,25 +15,17 @@ static uint32_t crc32ctable_le[LE_TABLE_ROWS][256];
  * fact that crctable[i^j] = crctable[i] ^ crctable[j].
  *
  */
-static void crc32init_le_generic(const uint32_t polynomial,
-				 uint32_t (*tab)[256])
+static void crc32init_le_generic(const uint32_t polynomial, uint32_t tab[256])
 {
 	unsigned i, j;
 	uint32_t crc = 1;
 
-	tab[0][0] = 0;
+	tab[0] = 0;
 
-	for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
+	for (i = 128; i; i >>= 1) {
 		crc = (crc >> 1) ^ ((crc & 1) ? polynomial : 0);
-		for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
-			tab[0][i + j] = crc ^ tab[0][j];
-	}
-	for (i = 0; i < LE_TABLE_SIZE; i++) {
-		crc = tab[0][i];
-		for (j = 1; j < LE_TABLE_ROWS; j++) {
-			crc = tab[0][crc & 0xff] ^ (crc >> 8);
-			tab[j][i] = crc;
-		}
+		for (j = 0; j < 256; j += 2 * i)
+			tab[i + j] = crc ^ tab[j];
 	}
 }
 
@@ -74,34 +47,22 @@ static void crc32init_be(void)
 	unsigned i, j;
 	uint32_t crc = 0x80000000;
 
-	crc32table_be[0][0] = 0;
+	crc32table_be[0] = 0;
 
-	for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
+	for (i = 1; i < 256; i <<= 1) {
 		crc = (crc << 1) ^ ((crc & 0x80000000) ? CRC32_POLY_BE : 0);
 		for (j = 0; j < i; j++)
-			crc32table_be[0][i + j] = crc ^ crc32table_be[0][j];
-	}
-	for (i = 0; i < BE_TABLE_SIZE; i++) {
-		crc = crc32table_be[0][i];
-		for (j = 1; j < BE_TABLE_ROWS; j++) {
-			crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8);
-			crc32table_be[j][i] = crc;
-		}
+			crc32table_be[i + j] = crc ^ crc32table_be[j];
 	}
 }
 
-static void output_table(uint32_t (*table)[256], int rows, int len, char *trans)
+static void output_table(const uint32_t table[256])
 {
-	int i, j;
-
-	for (j = 0 ; j < rows; j++) {
-		printf("{");
-		for (i = 0; i < len - 1; i++) {
-			if (i % ENTRIES_PER_LINE == 0)
-				printf("\n");
-			printf("%s(0x%8.8xL), ", trans, table[j][i]);
-		}
-		printf("%s(0x%8.8xL)},\n", trans, table[j][len - 1]);
+	int i;
+
+	for (i = 0; i < 256; i += 4) {
+		printf("\t0x%08x, 0x%08x, 0x%08x, 0x%08x,\n",
+		       table[i], table[i + 1], table[i + 2], table[i + 3]);
 	}
 }
 
@@ -109,34 +70,20 @@ int main(int argc, char** argv)
 {
 	printf("/* this file is generated - do not edit */\n\n");
 
-	if (CRC_LE_BITS > 1) {
-		crc32init_le();
-		printf("static const u32 ____cacheline_aligned "
-		       "crc32table_le[%d][%d] = {",
-		       LE_TABLE_ROWS, LE_TABLE_SIZE);
-		output_table(crc32table_le, LE_TABLE_ROWS,
-			     LE_TABLE_SIZE, "tole");
-		printf("};\n");
-	}
+	crc32init_le();
+	printf("static const u32 ____cacheline_aligned crc32table_le[256] = {\n");
+	output_table(crc32table_le);
+	printf("};\n");
 
-	if (CRC_BE_BITS > 1) {
-		crc32init_be();
-		printf("static const u32 ____cacheline_aligned "
-		       "crc32table_be[%d][%d] = {",
-		       BE_TABLE_ROWS, BE_TABLE_SIZE);
-		output_table(crc32table_be, LE_TABLE_ROWS,
-			     BE_TABLE_SIZE, "tobe");
-		printf("};\n");
-	}
-	if (CRC_LE_BITS > 1) {
-		crc32cinit_le();
-		printf("static const u32 ____cacheline_aligned "
-		       "crc32ctable_le[%d][%d] = {",
-		       LE_TABLE_ROWS, LE_TABLE_SIZE);
-		output_table(crc32ctable_le, LE_TABLE_ROWS,
-			     LE_TABLE_SIZE, "tole");
-		printf("};\n");
-	}
+	crc32init_be();
+	printf("static const u32 ____cacheline_aligned crc32table_be[256] = {\n");
+	output_table(crc32table_be);
+	printf("};\n");
+
+	crc32cinit_le();
+	printf("static const u32 ____cacheline_aligned crc32ctable_le[256] = {\n");
+	output_table(crc32ctable_le);
+	printf("};\n");
 
 	return 0;
 }