Commit 020b0215 authored by Andreas Dilger's avatar Andreas Dilger Committed by Greg Kroah-Hartman

staging: lustre: libcfs: add documentation for cfs_crypto_hash_*()

Add comment blocks for cfs_crypto_hash_*() in linux-crypto.c and
libcfs_crypto.h. Delete obsolete comment about shash handling in
cfs_crypto_hash_alloc().
Signed-off-by: default avatarAndreas Dilger <andreas.dilger@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5053
Reviewed-on: http://review.whamcloud.com/9990Reviewed-by: default avatarBob Glossman <bob.glossman@intel.com>
Reviewed-by: default avatarJames Simmons <uja.ornl@gmail.com>
Reviewed-by: default avatarOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 997e5188
......@@ -61,7 +61,14 @@ static struct cfs_crypto_hash_type hash_types[] = {
[CFS_HASH_ALG_SHA512] = { "sha512", 0, 64 },
};
/** Return pointer to type of hash for valid hash algorithm identifier */
/**
* Return hash algorithm information for the specified algorithm identifier
*
* Hash information includes algorithm name, initial seed, hash size.
*
* \retval cfs_crypto_hash_type for valid ID (CFS_HASH_ALG_*)
* \retval NULL for unknown algorithm identifier
*/
static inline const struct cfs_crypto_hash_type *
cfs_crypto_hash_type(unsigned char hash_alg)
{
......@@ -75,7 +82,14 @@ static inline const struct cfs_crypto_hash_type *
return NULL;
}
/** Return hash name for valid hash algorithm identifier or "unknown" */
/**
* Return hash name for hash algorithm identifier
*
* \param[in] hash_alg hash alrgorithm id (CFS_HASH_ALG_*)
*
* \retval string name of known hash algorithm
* \retval "unknown" if hash algorithm is unknown
*/
static inline const char *cfs_crypto_hash_name(unsigned char hash_alg)
{
const struct cfs_crypto_hash_type *ht;
......@@ -86,7 +100,14 @@ static inline const char *cfs_crypto_hash_name(unsigned char hash_alg)
return "unknown";
}
/** Return digest size for valid algorithm identifier or 0 */
/**
* Return digest size for hash algorithm type
*
* \param[in] hash_alg hash alrgorithm id (CFS_HASH_ALG_*)
*
* \retval hash algorithm digest size in bytes
* \retval 0 if hash algorithm type is unknown
*/
static inline int cfs_crypto_hash_digestsize(unsigned char hash_alg)
{
const struct cfs_crypto_hash_type *ht;
......@@ -97,7 +118,12 @@ static inline int cfs_crypto_hash_digestsize(unsigned char hash_alg)
return 0;
}
/** Return hash identifier for valid hash algorithm name or 0xFF */
/**
* Find hash algorithm ID for the specified algorithm name
*
* \retval hash algorithm ID for valid ID (CFS_HASH_ALG_*)
* \retval CFS_HASH_ALG_UNKNOWN for unknown algorithm name
*/
static inline unsigned char cfs_crypto_hash_alg(const char *algname)
{
unsigned char i;
......@@ -108,24 +134,6 @@ static inline unsigned char cfs_crypto_hash_alg(const char *algname)
return (i == CFS_HASH_ALG_MAX ? 0xFF : i);
}
/** Calculate hash digest for buffer.
* @param alg id of hash algorithm
* @param buf buffer of data
* @param buf_len buffer len
* @param key initial value for algorithm, if it is NULL,
* default initial value should be used.
* @param key_len len of initial value
* @param hash [out] pointer to hash, if it is NULL, hash_len is
* set to valid digest size in bytes, retval -ENOSPC.
* @param hash_len [in,out] size of hash buffer
* @returns status of operation
* @retval -EINVAL if buf, buf_len, hash_len or alg_id is invalid
* @retval -ENODEV if this algorithm is unsupported
* @retval -ENOSPC if pointer to hash is NULL, or hash_len less than
* digest size
* @retval 0 for success
* @retval < 0 other errors from lower layers.
*/
int cfs_crypto_hash_digest(unsigned char alg,
const void *buf, unsigned int buf_len,
unsigned char *key, unsigned int key_len,
......@@ -134,66 +142,17 @@ int cfs_crypto_hash_digest(unsigned char alg,
/* cfs crypto hash descriptor */
struct cfs_crypto_hash_desc;
/** Allocate and initialize descriptor for hash algorithm.
* @param alg algorithm id
* @param key initial value for algorithm, if it is NULL,
* default initial value should be used.
* @param key_len len of initial value
* @returns pointer to descriptor of hash instance
* @retval ERR_PTR(error) when errors occurred.
*/
struct cfs_crypto_hash_desc*
cfs_crypto_hash_init(unsigned char alg,
unsigned char *key, unsigned int key_len);
/** Update digest by part of data.
* @param desc hash descriptor
* @param page data page
* @param offset data offset
* @param len data len
* @returns status of operation
* @retval 0 for success.
*/
int cfs_crypto_hash_update_page(struct cfs_crypto_hash_desc *desc,
struct page *page, unsigned int offset,
unsigned int len);
/** Update digest by part of data.
* @param desc hash descriptor
* @param buf pointer to data buffer
* @param buf_len size of data at buffer
* @returns status of operation
* @retval 0 for success.
*/
int cfs_crypto_hash_update(struct cfs_crypto_hash_desc *desc, const void *buf,
unsigned int buf_len);
/** Finalize hash calculation, copy hash digest to buffer, destroy hash
* descriptor.
* @param desc hash descriptor
* @param hash buffer pointer to store hash digest
* @param hash_len pointer to hash buffer size, if NULL
* destroy hash descriptor
* @returns status of operation
* @retval -ENOSPC if hash is NULL, or *hash_len less than
* digest size
* @retval 0 for success
* @retval < 0 other errors from lower layers.
*/
int cfs_crypto_hash_final(struct cfs_crypto_hash_desc *desc,
unsigned char *hash, unsigned int *hash_len);
/**
* Register crypto hash algorithms
*/
int cfs_crypto_register(void);
/**
* Unregister
*/
void cfs_crypto_unregister(void);
/** Return hash speed in Mbytes per second for valid hash algorithm
* identifier. If test was unsuccessful -1 would be returned.
*/
int cfs_crypto_hash_speed(unsigned char hash_alg);
#endif
......@@ -32,11 +32,31 @@
#include "../../../include/linux/libcfs/libcfs.h"
#include "../../../include/linux/libcfs/libcfs_crypto.h"
#include "linux-crypto.h"
/**
* Array of hash algorithm speed in MByte per second
* Array of hash algorithm speed in MByte per second
*/
static int cfs_crypto_hash_speeds[CFS_HASH_ALG_MAX];
/**
* Initialize the state descriptor for the specified hash algorithm.
*
* An internal routine to allocate the hash-specific state in \a hdesc for
* use with cfs_crypto_hash_digest() to compute the hash of a single message,
* though possibly in multiple chunks. The descriptor internal state should
* be freed with cfs_crypto_hash_final().
*
* \param[in] hash_alg hash algorithm id (CFS_HASH_ALG_*)
* \param[out] type pointer to the hash description in hash_types[]
* array
* \param[in,out] hdesc hash state descriptor to be initialized
* \param[in] key initial hash value/state, NULL to use default
* value
* \param[in] key_len length of \a key
*
* \retval 0 on success
* \retval negative errno on failure
*/
static int cfs_crypto_hash_alloc(unsigned char alg_id,
const struct cfs_crypto_hash_type **type,
struct ahash_request **req,
......@@ -71,12 +91,6 @@ static int cfs_crypto_hash_alloc(unsigned char alg_id,
ahash_request_set_callback(*req, 0, NULL, NULL);
/** Shash have different logic for initialization then digest
* shash: crypto_hash_setkey, crypto_hash_init
* digest: crypto_digest_init, crypto_digest_setkey
* Skip this function for digest, because we use shash logic at
* cfs_crypto_hash_alloc.
*/
if (key)
err = crypto_ahash_setkey(tfm, key, key_len);
else if ((*type)->cht_key != 0)
......@@ -101,6 +115,32 @@ static int cfs_crypto_hash_alloc(unsigned char alg_id,
return err;
}
/**
* Calculate hash digest for the passed buffer.
*
* This should be used when computing the hash on a single contiguous buffer.
* It combines the hash initialization, computation, and cleanup.
*
* \param[in] hash_alg id of hash algorithm (CFS_HASH_ALG_*)
* \param[in] buf data buffer on which to compute hash
* \param[in] buf_len length of \a buf in bytes
* \param[in] key initial value/state for algorithm,
* if \a key = NULL use default initial value
* \param[in] key_len length of \a key in bytes
* \param[out] hash pointer to computed hash value,
* if \a hash = NULL then \a hash_len is to digest
* size in bytes, retval -ENOSPC
* \param[in,out] hash_len size of \a hash buffer
*
* \retval -EINVAL \a buf, \a buf_len, \a hash_len,
* \a alg_id invalid
* \retval -ENOENT \a hash_alg is unsupported
* \retval -ENOSPC \a hash is NULL, or \a hash_len less than
* digest size
* \retval 0 for success
* \retval negative errno for other errors from lower
* layers.
*/
int cfs_crypto_hash_digest(unsigned char alg_id,
const void *buf, unsigned int buf_len,
unsigned char *key, unsigned int key_len,
......@@ -135,6 +175,23 @@ int cfs_crypto_hash_digest(unsigned char alg_id,
}
EXPORT_SYMBOL(cfs_crypto_hash_digest);
/**
* Allocate and initialize desriptor for hash algorithm.
*
* This should be used to initialize a hash descriptor for multiple calls
* to a single hash function when computing the hash across multiple
* separate buffers or pages using cfs_crypto_hash_update{,_page}().
*
* The hash descriptor should be freed with cfs_crypto_hash_final().
*
* \param[in] hash_alg algorithm id (CFS_HASH_ALG_*)
* \param[in] key initial value/state for algorithm, if \a key = NULL
* use default initial value
* \param[in] key_len length of \a key in bytes
*
* \retval pointer to descriptor of hash instance
* \retval ERR_PTR(errno) in case of error
*/
struct cfs_crypto_hash_desc *
cfs_crypto_hash_init(unsigned char alg_id,
unsigned char *key, unsigned int key_len)
......@@ -151,6 +208,17 @@ struct cfs_crypto_hash_desc *
}
EXPORT_SYMBOL(cfs_crypto_hash_init);
/**
* Update hash digest computed on data within the given \a page
*
* \param[in] hdesc hash state descriptor
* \param[in] page data page on which to compute the hash
* \param[in] offset offset within \a page at which to start hash
* \param[in] len length of data on which to compute hash
*
* \retval 0 for success
* \retval negative errno on failure
*/
int cfs_crypto_hash_update_page(struct cfs_crypto_hash_desc *hdesc,
struct page *page, unsigned int offset,
unsigned int len)
......@@ -166,6 +234,16 @@ int cfs_crypto_hash_update_page(struct cfs_crypto_hash_desc *hdesc,
}
EXPORT_SYMBOL(cfs_crypto_hash_update_page);
/**
* Update hash digest computed on the specified data
*
* \param[in] hdesc hash state descriptor
* \param[in] buf data buffer on which to compute the hash
* \param[in] buf_len length of \buf on which to compute hash
*
* \retval 0 for success
* \retval negative errno on failure
*/
int cfs_crypto_hash_update(struct cfs_crypto_hash_desc *hdesc,
const void *buf, unsigned int buf_len)
{
......@@ -179,7 +257,18 @@ int cfs_crypto_hash_update(struct cfs_crypto_hash_desc *hdesc,
}
EXPORT_SYMBOL(cfs_crypto_hash_update);
/* If hash_len pointer is NULL - destroy descriptor. */
/**
* Finish hash calculation, copy hash digest to buffer, clean up hash descriptor
*
* \param[in] hdesc hash descriptor
* \param[out] hash pointer to hash buffer to store hash digest
* \param[in,out] hash_len pointer to hash buffer size, if \a hdesc = NULL
* only free \a hdesc instead of computing the hash
*
* \retval -ENOSPC if \a hash = NULL, or \a hash_len < digest size
* \retval 0 for success
* \retval negative errno for other errors from lower layers
*/
int cfs_crypto_hash_final(struct cfs_crypto_hash_desc *hdesc,
unsigned char *hash, unsigned int *hash_len)
{
......@@ -209,6 +298,17 @@ int cfs_crypto_hash_final(struct cfs_crypto_hash_desc *hdesc,
}
EXPORT_SYMBOL(cfs_crypto_hash_final);
/**
* Compute the speed of specified hash function
*
* Run a speed test on the given hash algorithm on buffer of the given size.
* The speed is stored internally in the cfs_crypto_hash_speeds[] array, and
* is available through the cfs_crypto_hash_speed() function.
*
* \param[in] hash_alg hash algorithm id (CFS_HASH_ALG_*)
* \param[in] buf data buffer on which to compute the hash
* \param[in] buf_len length of \buf on which to compute hash
*/
static void cfs_crypto_performance_test(unsigned char alg_id,
const unsigned char *buf,
unsigned int buf_len)
......@@ -243,6 +343,18 @@ static void cfs_crypto_performance_test(unsigned char alg_id,
cfs_crypto_hash_name(alg_id), cfs_crypto_hash_speeds[alg_id]);
}
/**
* hash speed in Mbytes per second for valid hash algorithm
*
* Return the performance of the specified \a hash_alg that was previously
* computed using cfs_crypto_performance_test().
*
* \param[in] hash_alg hash algorithm id (CFS_HASH_ALG_*)
*
* \retval positive speed of the hash function in MB/s
* \retval -ENOENT if \a hash_alg is unsupported
* \retval negative errno if \a hash_alg speed is unavailable
*/
int cfs_crypto_hash_speed(unsigned char hash_alg)
{
if (hash_alg < CFS_HASH_ALG_MAX)
......@@ -252,7 +364,22 @@ int cfs_crypto_hash_speed(unsigned char hash_alg)
EXPORT_SYMBOL(cfs_crypto_hash_speed);
/**
* Do performance test for all hash algorithms.
* Run the performance test for all hash algorithms.
*
* Run the cfs_crypto_performance_test() benchmark for all of the available
* hash functions using a 1MB buffer size. This is a reasonable buffer size
* for Lustre RPCs, even if the actual RPC size is larger or smaller.
*
* Since the setup cost and computation speed of various hash algorithms is
* a function of the buffer size (and possibly internal contention of offload
* engines), this speed only represents an estimate of the actual speed under
* actual usage, but is reasonable for comparing available algorithms.
*
* The actual speeds are available via cfs_crypto_hash_speed() for later
* comparison.
*
* \retval 0 on success
* \retval -ENOMEM if no memory is available for test buffer
*/
static int cfs_crypto_test_hashes(void)
{
......@@ -280,6 +407,11 @@ static int cfs_crypto_test_hashes(void)
static int adler32;
/**
* Register available hash functions
*
* \retval 0
*/
int cfs_crypto_register(void)
{
request_module("crc32c");
......@@ -291,6 +423,9 @@ int cfs_crypto_register(void)
return 0;
}
/**
* Unregister previously registered hash functions
*/
void cfs_crypto_unregister(void)
{
if (adler32 == 0)
......
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