mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-24 21:24:00 +08:00
877b5691f2
The flags field in 'struct shash_desc' never actually does anything. The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP. However, no shash algorithm ever sleeps, making this flag a no-op. With this being the case, inevitably some users who can't sleep wrongly pass MAY_SLEEP. These would all need to be fixed if any shash algorithm actually started sleeping. For example, the shash_ahash_*() functions, which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP from the ahash API to the shash API. However, the shash functions are called under kmap_atomic(), so actually they're assumed to never sleep. Even if it turns out that some users do need preemption points while hashing large buffers, we could easily provide a helper function crypto_shash_update_large() which divides the data into smaller chunks and calls crypto_shash_update() and cond_resched() for each chunk. It's not necessary to have a flag in 'struct shash_desc', nor is it necessary to make individual shash algorithms aware of this at all. Therefore, remove shash_desc::flags, and document that the crypto_shash_*() functions can be called from any context. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
86 lines
2.2 KiB
C
86 lines
2.2 KiB
C
/*
|
|
* CRC32C
|
|
*@Article{castagnoli-crc,
|
|
* author = { Guy Castagnoli and Stefan Braeuer and Martin Herrman},
|
|
* title = {{Optimization of Cyclic Redundancy-Check Codes with 24
|
|
* and 32 Parity Bits}},
|
|
* journal = IEEE Transactions on Communication,
|
|
* year = {1993},
|
|
* volume = {41},
|
|
* number = {6},
|
|
* pages = {},
|
|
* month = {June},
|
|
*}
|
|
* Used by the iSCSI driver, possibly others, and derived from the
|
|
* the iscsi-crc.c module of the linux-iscsi driver at
|
|
* http://linux-iscsi.sourceforge.net.
|
|
*
|
|
* Following the example of lib/crc32, this function is intended to be
|
|
* flexible and useful for all users. Modules that currently have their
|
|
* own crc32c, but hopefully may be able to use this one are:
|
|
* net/sctp (please add all your doco to here if you change to
|
|
* use this one!)
|
|
* <endoflist>
|
|
*
|
|
* Copyright (c) 2004 Cisco Systems, Inc.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the Free
|
|
* Software Foundation; either version 2 of the License, or (at your option)
|
|
* any later version.
|
|
*
|
|
*/
|
|
|
|
#include <crypto/hash.h>
|
|
#include <linux/err.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/crc32c.h>
|
|
|
|
static struct crypto_shash *tfm;
|
|
|
|
u32 crc32c(u32 crc, const void *address, unsigned int length)
|
|
{
|
|
SHASH_DESC_ON_STACK(shash, tfm);
|
|
u32 ret, *ctx = (u32 *)shash_desc_ctx(shash);
|
|
int err;
|
|
|
|
shash->tfm = tfm;
|
|
*ctx = crc;
|
|
|
|
err = crypto_shash_update(shash, address, length);
|
|
BUG_ON(err);
|
|
|
|
ret = *ctx;
|
|
barrier_data(ctx);
|
|
return ret;
|
|
}
|
|
|
|
EXPORT_SYMBOL(crc32c);
|
|
|
|
static int __init libcrc32c_mod_init(void)
|
|
{
|
|
tfm = crypto_alloc_shash("crc32c", 0, 0);
|
|
return PTR_ERR_OR_ZERO(tfm);
|
|
}
|
|
|
|
static void __exit libcrc32c_mod_fini(void)
|
|
{
|
|
crypto_free_shash(tfm);
|
|
}
|
|
|
|
const char *crc32c_impl(void)
|
|
{
|
|
return crypto_shash_driver_name(tfm);
|
|
}
|
|
EXPORT_SYMBOL(crc32c_impl);
|
|
|
|
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");
|
|
MODULE_SOFTDEP("pre: crc32c");
|