libcrc32c: Move implementation to crypto crc32c

This patch swaps the role of libcrc32c and crc32c.  Previously
the implementation was in libcrc32c and crc32c was a wrapper.
Now the code is in crc32c and libcrc32c just calls the crypto
layer.

The reason for the change is to tap into the algorithm selection
capability of the crypto API so that optimised implementations
such as the one utilising Intel's CRC32C instruction can be
used where available.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 33 insertions, 150 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 85cf7ea..ce303f1 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -64,6 +64,7 @@ config CRC7
 
 config LIBCRC32C
 	tristate "CRC32c (Castagnoli, et al) Cyclic Redundancy-Check"
+	select CRYPTO_CRC32C
 	help
 	  This option is provided for the case where no in-kernel-tree
 	  modules require CRC32c functions, but a module built outside the
diff --git a/lib/libcrc32c.c b/lib/libcrc32c.c
index b5c3287..38b17ab 100644
--- a/lib/libcrc32c.c
+++ b/lib/libcrc32c.c
@@ -30,168 +30,50 @@
  * any later version.
  *
  */
-#include <linux/crc32c.h>
-#include <linux/compiler.h>
-#include <linux/module.h>
-
-MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
-MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
-MODULE_LICENSE("GPL");
-
-#define CRC32C_POLY_BE 0x1EDC6F41
-#define CRC32C_POLY_LE 0x82F63B78
 
-#ifndef CRC_LE_BITS 
-# define CRC_LE_BITS 8
-#endif
-
-
-/*
- * Haven't generated a big-endian table yet, but the bit-wise version
- * should at least work.
- */
-#if defined CRC_BE_BITS && CRC_BE_BITS != 1
-#undef CRC_BE_BITS
-#endif
-#ifndef CRC_BE_BITS
-# define CRC_BE_BITS 1
-#endif
+#include <crypto/hash.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
 
-EXPORT_SYMBOL(crc32c_le);
+static struct crypto_shash *tfm;
 
-#if CRC_LE_BITS == 1
-/*
- * Compute things bit-wise, as done in crc32.c.  We could share the tight 
- * loop below with crc32 and vary the POLY if we don't find value in terms
- * of space and maintainability in keeping the two modules separate.
- */
-u32 __pure
-crc32c_le(u32 crc, unsigned char const *p, size_t len)
+u32 crc32c(u32 crc, const void *address, unsigned int length)
 {
-	int i;
-	while (len--) {
-		crc ^= *p++;
-		for (i = 0; i < 8; i++)
-			crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
-	}
-	return crc;
-}
-#else
+	struct {
+		struct shash_desc shash;
+		char ctx[crypto_shash_descsize(tfm)];
+	} desc;
+	int err;
 
-/*
- * This is the CRC-32C table
- * Generated with:
- * width = 32 bits
- * poly = 0x1EDC6F41
- * reflect input bytes = true
- * reflect output bytes = true
- */
+	desc.shash.tfm = tfm;
+	desc.shash.flags = 0;
+	*(u32 *)desc.ctx = crc;
 
-static const u32 crc32c_table[256] = {
-	0x00000000L, 0xF26B8303L, 0xE13B70F7L, 0x1350F3F4L,
-	0xC79A971FL, 0x35F1141CL, 0x26A1E7E8L, 0xD4CA64EBL,
-	0x8AD958CFL, 0x78B2DBCCL, 0x6BE22838L, 0x9989AB3BL,
-	0x4D43CFD0L, 0xBF284CD3L, 0xAC78BF27L, 0x5E133C24L,
-	0x105EC76FL, 0xE235446CL, 0xF165B798L, 0x030E349BL,
-	0xD7C45070L, 0x25AFD373L, 0x36FF2087L, 0xC494A384L,
-	0x9A879FA0L, 0x68EC1CA3L, 0x7BBCEF57L, 0x89D76C54L,
-	0x5D1D08BFL, 0xAF768BBCL, 0xBC267848L, 0x4E4DFB4BL,
-	0x20BD8EDEL, 0xD2D60DDDL, 0xC186FE29L, 0x33ED7D2AL,
-	0xE72719C1L, 0x154C9AC2L, 0x061C6936L, 0xF477EA35L,
-	0xAA64D611L, 0x580F5512L, 0x4B5FA6E6L, 0xB93425E5L,
-	0x6DFE410EL, 0x9F95C20DL, 0x8CC531F9L, 0x7EAEB2FAL,
-	0x30E349B1L, 0xC288CAB2L, 0xD1D83946L, 0x23B3BA45L,
-	0xF779DEAEL, 0x05125DADL, 0x1642AE59L, 0xE4292D5AL,
-	0xBA3A117EL, 0x4851927DL, 0x5B016189L, 0xA96AE28AL,
-	0x7DA08661L, 0x8FCB0562L, 0x9C9BF696L, 0x6EF07595L,
-	0x417B1DBCL, 0xB3109EBFL, 0xA0406D4BL, 0x522BEE48L,
-	0x86E18AA3L, 0x748A09A0L, 0x67DAFA54L, 0x95B17957L,
-	0xCBA24573L, 0x39C9C670L, 0x2A993584L, 0xD8F2B687L,
-	0x0C38D26CL, 0xFE53516FL, 0xED03A29BL, 0x1F682198L,
-	0x5125DAD3L, 0xA34E59D0L, 0xB01EAA24L, 0x42752927L,
-	0x96BF4DCCL, 0x64D4CECFL, 0x77843D3BL, 0x85EFBE38L,
-	0xDBFC821CL, 0x2997011FL, 0x3AC7F2EBL, 0xC8AC71E8L,
-	0x1C661503L, 0xEE0D9600L, 0xFD5D65F4L, 0x0F36E6F7L,
-	0x61C69362L, 0x93AD1061L, 0x80FDE395L, 0x72966096L,
-	0xA65C047DL, 0x5437877EL, 0x4767748AL, 0xB50CF789L,
-	0xEB1FCBADL, 0x197448AEL, 0x0A24BB5AL, 0xF84F3859L,
-	0x2C855CB2L, 0xDEEEDFB1L, 0xCDBE2C45L, 0x3FD5AF46L,
-	0x7198540DL, 0x83F3D70EL, 0x90A324FAL, 0x62C8A7F9L,
-	0xB602C312L, 0x44694011L, 0x5739B3E5L, 0xA55230E6L,
-	0xFB410CC2L, 0x092A8FC1L, 0x1A7A7C35L, 0xE811FF36L,
-	0x3CDB9BDDL, 0xCEB018DEL, 0xDDE0EB2AL, 0x2F8B6829L,
-	0x82F63B78L, 0x709DB87BL, 0x63CD4B8FL, 0x91A6C88CL,
-	0x456CAC67L, 0xB7072F64L, 0xA457DC90L, 0x563C5F93L,
-	0x082F63B7L, 0xFA44E0B4L, 0xE9141340L, 0x1B7F9043L,
-	0xCFB5F4A8L, 0x3DDE77ABL, 0x2E8E845FL, 0xDCE5075CL,
-	0x92A8FC17L, 0x60C37F14L, 0x73938CE0L, 0x81F80FE3L,
-	0x55326B08L, 0xA759E80BL, 0xB4091BFFL, 0x466298FCL,
-	0x1871A4D8L, 0xEA1A27DBL, 0xF94AD42FL, 0x0B21572CL,
-	0xDFEB33C7L, 0x2D80B0C4L, 0x3ED04330L, 0xCCBBC033L,
-	0xA24BB5A6L, 0x502036A5L, 0x4370C551L, 0xB11B4652L,
-	0x65D122B9L, 0x97BAA1BAL, 0x84EA524EL, 0x7681D14DL,
-	0x2892ED69L, 0xDAF96E6AL, 0xC9A99D9EL, 0x3BC21E9DL,
-	0xEF087A76L, 0x1D63F975L, 0x0E330A81L, 0xFC588982L,
-	0xB21572C9L, 0x407EF1CAL, 0x532E023EL, 0xA145813DL,
-	0x758FE5D6L, 0x87E466D5L, 0x94B49521L, 0x66DF1622L,
-	0x38CC2A06L, 0xCAA7A905L, 0xD9F75AF1L, 0x2B9CD9F2L,
-	0xFF56BD19L, 0x0D3D3E1AL, 0x1E6DCDEEL, 0xEC064EEDL,
-	0xC38D26C4L, 0x31E6A5C7L, 0x22B65633L, 0xD0DDD530L,
-	0x0417B1DBL, 0xF67C32D8L, 0xE52CC12CL, 0x1747422FL,
-	0x49547E0BL, 0xBB3FFD08L, 0xA86F0EFCL, 0x5A048DFFL,
-	0x8ECEE914L, 0x7CA56A17L, 0x6FF599E3L, 0x9D9E1AE0L,
-	0xD3D3E1ABL, 0x21B862A8L, 0x32E8915CL, 0xC083125FL,
-	0x144976B4L, 0xE622F5B7L, 0xF5720643L, 0x07198540L,
-	0x590AB964L, 0xAB613A67L, 0xB831C993L, 0x4A5A4A90L,
-	0x9E902E7BL, 0x6CFBAD78L, 0x7FAB5E8CL, 0x8DC0DD8FL,
-	0xE330A81AL, 0x115B2B19L, 0x020BD8EDL, 0xF0605BEEL,
-	0x24AA3F05L, 0xD6C1BC06L, 0xC5914FF2L, 0x37FACCF1L,
-	0x69E9F0D5L, 0x9B8273D6L, 0x88D28022L, 0x7AB90321L,
-	0xAE7367CAL, 0x5C18E4C9L, 0x4F48173DL, 0xBD23943EL,
-	0xF36E6F75L, 0x0105EC76L, 0x12551F82L, 0xE03E9C81L,
-	0x34F4F86AL, 0xC69F7B69L, 0xD5CF889DL, 0x27A40B9EL,
-	0x79B737BAL, 0x8BDCB4B9L, 0x988C474DL, 0x6AE7C44EL,
-	0xBE2DA0A5L, 0x4C4623A6L, 0x5F16D052L, 0xAD7D5351L
-};
+	err = crypto_shash_update(&desc.shash, address, length);
+	BUG_ON(err);
 
-/*
- * Steps through buffer one byte at at time, calculates reflected 
- * crc using table.
- */
+	return *(u32 *)desc.ctx;
+}
 
-u32 __pure
-crc32c_le(u32 crc, unsigned char const *data, size_t length)
+static int __init libcrc32c_mod_init(void)
 {
-	while (length--)
-		crc =
-		    crc32c_table[(crc ^ *data++) & 0xFFL] ^ (crc >> 8);
+	tfm = crypto_alloc_shash("crc32c", 0, 0);
+	if (IS_ERR(tfm))
+		return PTR_ERR(tfm);
 
-	return crc;
+	return 0;
 }
 
-#endif	/* CRC_LE_BITS == 8 */
-
-EXPORT_SYMBOL(crc32c_be);
-
-#if CRC_BE_BITS == 1
-u32 __pure
-crc32c_be(u32 crc, unsigned char const *p, size_t len)
+static void __exit libcrc32c_mod_fini(void)
 {
-	int i;
-	while (len--) {
-		crc ^= *p++ << 24;
-		for (i = 0; i < 8; i++)
-			crc =
-			    (crc << 1) ^ ((crc & 0x80000000) ? CRC32C_POLY_BE :
-					  0);
-	}
-	return crc;
+	crypto_free_shash(tfm);
 }
-#endif
 
-/*
- * Unit test
- *
- * A small unit test suite is implemented as part of the crypto suite.
- * Select CRYPTO_CRC32C and use the tcrypt module to run the tests.
- */
+module_init(libcrc32c_mod_init);
+module_exit(libcrc32c_mod_fini);
+
+MODULE_AUTHOR("Clay Haapala <chaapala@cisco.com>");
+MODULE_DESCRIPTION("CRC32c (Castagnoli) calculations");
+MODULE_LICENSE("GPL");