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Diffstat (limited to 'fs/crypto/fscrypt_private.h')
| -rw-r--r-- | fs/crypto/fscrypt_private.h | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index 8371e4e1f596..25bcfcc2d706 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -27,6 +27,23 @@ */ #define FSCRYPT_MIN_KEY_SIZE 16 +/* + * This mask is passed as the third argument to the crypto_alloc_*() functions + * to prevent fscrypt from using the Crypto API drivers for non-inline crypto + * engines. Those drivers have been problematic for fscrypt. fscrypt users + * have reported hangs and even incorrect en/decryption with these drivers. + * Since going to the driver, off CPU, and back again is really slow, such + * drivers can be over 50 times slower than the CPU-based code for fscrypt's + * workload. Even on platforms that lack AES instructions on the CPU, using the + * offloads has been shown to be slower, even staying with AES. (Of course, + * Adiantum is faster still, and is the recommended option on such platforms...) + * + * Note that fscrypt also supports inline crypto engines. Those don't use the + * Crypto API and work much better than the old-style (non-inline) engines. + */ +#define FSCRYPT_CRYPTOAPI_MASK \ + (CRYPTO_ALG_ALLOCATES_MEMORY | CRYPTO_ALG_KERN_DRIVER_ONLY) + #define FSCRYPT_CONTEXT_V1 1 #define FSCRYPT_CONTEXT_V2 2 |