From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: [PATCH 2/3] dm: add support for passing through inline crypto support Date: Wed, 23 Sep 2020 21:21:03 -0400 Message-ID: <20200924012103.GE10500@redhat.com> References: <20200909234422.76194-1-satyat@google.com> <20200909234422.76194-3-satyat@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200909234422.76194-3-satyat@google.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com Content-Disposition: inline To: Satya Tangirala Cc: Jens Axboe , Eric Biggers , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, dm-devel@redhat.com, Alasdair Kergon List-Id: dm-devel.ids On Wed, Sep 09 2020 at 7:44pm -0400, Satya Tangirala wrote: > From: Eric Biggers > > Update the device-mapper core to support exposing the inline crypto > support of the underlying device(s) through the device-mapper device. > > This works by creating a "passthrough keyslot manager" for the dm > device, which declares support for encryption settings which all > underlying devices support. When a supported setting is used, the bio > cloning code handles cloning the crypto context to the bios for all the > underlying devices. When an unsupported setting is used, the blk-crypto > fallback is used as usual. > > Crypto support on each underlying device is ignored unless the > corresponding dm target opts into exposing it. This is needed because > for inline crypto to semantically operate on the original bio, the data > must not be transformed by the dm target. Thus, targets like dm-linear > can expose crypto support of the underlying device, but targets like > dm-crypt can't. (dm-crypt could use inline crypto itself, though.) > > When a key is evicted from the dm device, it is evicted from all > underlying devices. > > Signed-off-by: Eric Biggers > Co-developed-by: Satya Tangirala > Signed-off-by: Satya Tangirala > --- > block/blk-crypto.c | 1 + > block/keyslot-manager.c | 34 ++++++++++++ > drivers/md/dm-core.h | 4 ++ > drivers/md/dm-table.c | 52 +++++++++++++++++++ > drivers/md/dm.c | 92 ++++++++++++++++++++++++++++++++- > include/linux/device-mapper.h | 6 +++ > include/linux/keyslot-manager.h | 7 +++ > 7 files changed, 195 insertions(+), 1 deletion(-) > > diff --git a/block/blk-crypto.c b/block/blk-crypto.c > index 2d5e60023b08..33555cf0e3e7 100644 > --- a/block/blk-crypto.c > +++ b/block/blk-crypto.c > @@ -402,3 +402,4 @@ int blk_crypto_evict_key(struct request_queue *q, > */ > return blk_crypto_fallback_evict_key(key); > } > +EXPORT_SYMBOL_GPL(blk_crypto_evict_key); > diff --git a/block/keyslot-manager.c b/block/keyslot-manager.c > index 60ac406d54b9..e0f776c38d8a 100644 > --- a/block/keyslot-manager.c > +++ b/block/keyslot-manager.c > @@ -416,6 +416,40 @@ void blk_ksm_unregister(struct request_queue *q) > { > q->ksm = NULL; > } > +EXPORT_SYMBOL_GPL(blk_ksm_unregister); > + > +/** > + * blk_ksm_intersect_modes() - restrict supported modes by child device > + * @parent: The keyslot manager for parent device > + * @child: The keyslot manager for child device, or NULL > + * > + * Clear any crypto mode support bits in @parent that aren't set in @child. > + * If @child is NULL, then all parent bits are cleared. > + * > + * Only use this when setting up the keyslot manager for a layered device, > + * before it's been exposed yet. > + */ > +void blk_ksm_intersect_modes(struct blk_keyslot_manager *parent, > + const struct blk_keyslot_manager *child) > +{ > + if (child) { > + unsigned int i; > + > + parent->max_dun_bytes_supported = > + min(parent->max_dun_bytes_supported, > + child->max_dun_bytes_supported); > + for (i = 0; i < ARRAY_SIZE(child->crypto_modes_supported); > + i++) { > + parent->crypto_modes_supported[i] &= > + child->crypto_modes_supported[i]; > + } > + } else { > + parent->max_dun_bytes_supported = 0; > + memset(parent->crypto_modes_supported, 0, > + sizeof(parent->crypto_modes_supported)); > + } > +} > +EXPORT_SYMBOL_GPL(blk_ksm_intersect_modes); > > /** > * blk_ksm_init_passthrough() - Init a passthrough keyslot manager > diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h > index c4ef1fceead6..4542050eebfc 100644 > --- a/drivers/md/dm-core.h > +++ b/drivers/md/dm-core.h > @@ -12,6 +12,7 @@ > #include > #include > #include > +#include > > #include > > @@ -49,6 +50,9 @@ struct mapped_device { > > int numa_node_id; > struct request_queue *queue; > +#ifdef CONFIG_BLK_INLINE_ENCRYPTION > + struct blk_keyslot_manager ksm; > +#endif > > atomic_t holders; > atomic_t open_count; Any reason you placed the ksm member where you did? Looking at 'struct blk_keyslot_manager' I'm really hating adding that bloat to every DM device for a feature that really won't see much broad use (AFAIK). Any chance you could allocate 'struct blk_keyslot_manager' as needed so that most users of DM would only be carrying 1 extra pointer (set to NULL)? Thanks, Mike