nfsd: Use MD5 library instead of crypto_shash

Update NFSD's support for "legacy client tracking" (which uses MD5) to
use the MD5 library instead of crypto_shash.  This has several benefits:

- Simpler code.  Notably, much of the error-handling code is no longer
  needed, since the library functions can't fail.

- Improved performance due to reduced overhead.  A microbenchmark of
  nfs4_make_rec_clidname() shows a speedup from 1455 cycles to 425.

- The MD5 code can now safely be built as a loadable module when nfsd is
  built as a loadable module.  (Previously, nfsd forced the MD5 code to
  built-in, presumably to work around the unreliability of the
  name-based loading.)  Thus select MD5 from the tristate option NFSD if
  NFSD_LEGACY_CLIENT_TRACKING, instead of from the bool option NFSD_V4.

- Fixes a bug where legacy client tracking was not supported on kernels
  booted with "fips=1", due to crypto_shash not allowing MD5 to be used.
  This particular use of MD5 is not for a cryptographic purpose, though,
  so it is acceptable even when fips=1 (see
  https://lore.kernel.org/r/dae495a93cbcc482f4ca23c3a0d9360a1fd8c3a8.camel@redhat.com/).

Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Scott Mayhew <smayhew@redhat.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

0 files changed, 0 insertions, 0 deletions