From: Eric Biggers <ebiggers@kernel.org>
To: Satya Tangirala <satyaprateek2357@gmail.com>
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Jens Axboe <axboe@kernel.dk>, Satya Tangirala <satyat@google.com>
Subject: Re: [PATCH v4 7/9] dm: handle error from blk_ksm_register()
Date: Fri, 23 Jul 2021 10:26:48 -0700 [thread overview]
Message-ID: <YPr71wM9IFdWY9FK@gmail.com> (raw)
In-Reply-To: <20210707052943.3960-8-satyaprateek2357@gmail.com>
On Tue, Jul 06, 2021 at 10:29:41PM -0700, Satya Tangirala wrote:
> From: Satya Tangirala <satyat@google.com>
>
> Handle any error from blk_ksm_register() in the callers. Previously,
> the callers ignored the return value because blk_ksm_register() wouldn't
> fail as long as the request_queue didn't have integrity support too, but
> as this is no longer the case, it's safer for the callers to just handle
> the return value appropriately.
>
> Signed-off-by: Satya Tangirala <satyat@google.com>
> ---
> drivers/md/dm-table.c | 17 ++++++++++++++++-
> 1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
> index 29cbfc3e3c4b..c79c0fbe80dd 100644
> --- a/drivers/md/dm-table.c
> +++ b/drivers/md/dm-table.c
> @@ -1343,6 +1343,20 @@ static int dm_table_construct_keyslot_manager(struct dm_table *t)
> */
> t->ksm = ksm;
>
> + /*
> + * At this point, t->ksm is either NULL or *not* empty (i.e. will support
> + * at least 1 crypto capability), the request queue doesn't support
> + * integrity, and it also satisfies all the block layer constraints
> + * "sufficiently" (as in the constraints of the DM device's request queue
> + * won't preclude any of the intersection of the supported capabilities
> + * of the underlying devices, since if some capability were precluded by
> + * the DM device's request queue's constraints, that capability would
> + * also have been precluded by one of the child device's request queues).
> + *
> + * Hence any future attempt to call blk_ksm_register() on t->ksm (if it's
> + * not NULL) will succeed.
> + */
> +
> return 0;
I don't think this properly answers the question I had on the previous version
of this patch, which was not just how we know that blk_ksm_register() will
succeed later, but also how we know that the blk_ksm_is_superset() check done
above is valid when some of the crypto capabilities may be cleared by
blk_ksm_register() later. Is the assumption actually that in the device-mapper
case, blk_ksm_register() will never clear any crypto capabilities at all?
If so, can that be explained properly?
- Eric
next prev parent reply other threads:[~2021-07-23 17:26 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-07 5:29 [PATCH v4 0/9] ensure bios aren't split in middle of crypto data unit Satya Tangirala
2021-07-07 5:29 ` [PATCH v4 1/9] block: introduce blk_ksm_is_empty() Satya Tangirala
2021-07-23 16:45 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 2/9] block: blk-crypto: introduce blk_crypto_bio_sectors_alignment() Satya Tangirala
2021-07-23 16:45 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 3/9] block: introduce bio_required_sector_alignment() Satya Tangirala
2021-07-23 16:46 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 4/9] block: keyslot-manager: introduce blk_ksm_restrict_dus_to_queue_limits() Satya Tangirala
2021-07-23 17:08 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 5/9] ufshcd: handle error from blk_ksm_register() Satya Tangirala
2021-07-23 17:13 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 6/9] mmc: " Satya Tangirala
2021-07-07 5:29 ` [PATCH v4 7/9] dm: " Satya Tangirala
2021-07-23 17:26 ` Eric Biggers [this message]
2021-07-07 5:29 ` [PATCH v4 8/9] blk-merge: Ensure bios aren't split in middle of a crypto data unit Satya Tangirala
2021-07-23 18:11 ` Eric Biggers
2021-07-07 5:29 ` [PATCH v4 9/9] block: add WARN_ON_ONCE() to bio_split() for sector alignment Satya Tangirala
2021-07-23 17:30 ` Eric Biggers
2021-07-23 16:49 ` [PATCH v4 0/9] ensure bios aren't split in middle of crypto data unit Eric Biggers
2021-07-23 17:52 ` Eric Biggers
2021-07-24 7:36 ` Christoph Hellwig
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