| Message ID | 20181206045413.32531-1-ebiggers@kernel.org (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Herbert Xu |
| Headers | show |
| Series | dm verity: log the hash algorithm implementation | expand |
On Thu, 6 Dec 2018 at 05:54, Eric Biggers <ebiggers@kernel.org> wrote: > > From: Eric Biggers <ebiggers@google.com> > > Log the hash algorithm's driver name when a dm-verity target is created. > This will help people determine whether the expected implementation is > being used. It can make an enormous difference; e.g., SHA-256 on ARM > can be 8x faster with the crypto extensions than without. It can also > be useful to know if an implementation using an external crypto > accelerator is being used instead of a software implementation. > > Example message: > > [ 35.281945] device-mapper: verity: sha256 using implementation "sha256-ce" > > We've already found the similar message in fs/crypto/keyinfo.c to be > very useful. > > Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> > --- > drivers/md/dm-verity-target.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c > index fc65f0dedf7f..f4c31ffaa88e 100644 > --- a/drivers/md/dm-verity-target.c > +++ b/drivers/md/dm-verity-target.c > @@ -1040,6 +1040,15 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) > v->tfm = NULL; > goto bad; > } > + > + /* > + * dm-verity performance can vary greatly depending on which hash > + * algorithm implementation is used. Help people debug performance > + * problems by logging the ->cra_driver_name. > + */ > + DMINFO("%s using implementation \"%s\"", v->alg_name, > + crypto_hash_alg_common(v->tfm)->base.cra_driver_name); > + > v->digest_size = crypto_ahash_digestsize(v->tfm); > if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { > ti->error = "Digest size too big"; > -- > 2.19.2 >
diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index fc65f0dedf7f..f4c31ffaa88e 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -1040,6 +1040,15 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv) v->tfm = NULL; goto bad; } + + /* + * dm-verity performance can vary greatly depending on which hash + * algorithm implementation is used. Help people debug performance + * problems by logging the ->cra_driver_name. + */ + DMINFO("%s using implementation \"%s\"", v->alg_name, + crypto_hash_alg_common(v->tfm)->base.cra_driver_name); + v->digest_size = crypto_ahash_digestsize(v->tfm); if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) { ti->error = "Digest size too big";