linux.git/drivers/md/dm-crypt.c, branch v5.14

dm crypt: Fix zoned block device support

2021-06-04T16:07:38+00:00

Zone append BIOs (REQ_OP_ZONE_APPEND) always specify the start sector
of the zone to be written instead of the actual sector location to
write. The write location is determined by the device and returned to
the host upon completion of the operation. This interface, while simple
and efficient for writing into sequential zones of a zoned block
device, is incompatible with the use of sector values to calculate a
cypher block IV. All data written in a zone end up using the same IV
values corresponding to the first sectors of the zone, but read
operation will specify any sector within the zone resulting in an IV
mismatch between encryption and decryption.

To solve this problem, report to DM core that zone append operations are
not supported. This result in the zone append operations being emulated
using regular write operations.

Reported-by: Shin'ichiro Kawasaki 
Signed-off-by: Damien Le Moal 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Snitzer

dm: Introduce dm_report_zones()

2021-06-04T16:07:32+00:00

To simplify the implementation of the report_zones operation of a zoned
target, introduce the function dm_report_zones() to set a target
mapping start sector in struct dm_report_zones_args and call
blkdev_report_zones(). This new function is exported and the report
zones callback function dm_report_zones_cb() is not.

dm-linear, dm-flakey and dm-crypt are modified to use dm_report_zones().

Signed-off-by: Damien Le Moal 
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Himanshu Madhani 
Signed-off-by: Mike Snitzer

block: rename BIO_MAX_PAGES to BIO_MAX_VECS

2021-03-11T14:47:48+00:00

Ever since the addition of multipage bio_vecs BIO_MAX_PAGES has been
horribly confusingly misnamed.  Rename it to BIO_MAX_VECS to stop
confusing users of the bio API.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Matthew Wilcox (Oracle) 
Reviewed-by: Martin K. Petersen 
Link: https://lore.kernel.org/r/20210311110137.1132391-2-hch@lst.de
Signed-off-by: Jens Axboe

dm: fix deadlock when swapping to encrypted device

2021-02-11T14:45:28+00:00

The system would deadlock when swapping to a dm-crypt device. The reason
is that for each incoming write bio, dm-crypt allocates memory that holds
encrypted data. These excessive allocations exhaust all the memory and the
result is either deadlock or OOM trigger.

This patch limits the number of in-flight swap bios, so that the memory
consumed by dm-crypt is limited. The limit is enforced if the target set
the "limit_swap_bios" variable and if the bio has REQ_SWAP set.

Non-swap bios are not affected becuase taking the semaphore would cause
performance degradation.

This is similar to request-based drivers - they will also block when the
number of requests is over the limit.

Signed-off-by: Mikulas Patocka 
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer

dm: simplify target code conditional on CONFIG_BLK_DEV_ZONED

2021-02-11T14:45:27+00:00

Allow removal of CONFIG_BLK_DEV_ZONED conditionals in target_type
definition of various targets.

Suggested-by: Eric Biggers 
Signed-off-by: Mike Snitzer

dm crypt: support using trusted keys

2021-02-03T15:13:00+00:00

Commit 27f5411a718c ("dm crypt: support using encrypted keys") extended
dm-crypt to allow use of "encrypted" keys along with "user" and "logon".

Along the same lines, teach dm-crypt to support "trusted" keys as well.

Signed-off-by: Ahmad Fatoum 
Signed-off-by: Mike Snitzer

dm crypt: replaced #if defined with IS_ENABLED

2021-02-03T15:12:31+00:00

IS_ENABLED(CONFIG_ENCRYPTED_KEYS) is true whether the option is built-in
or a module, so use it instead of #if defined checking for each
separately.

The other #if was to avoid a static function defined, but unused
warning. As we now always build the callsite when the function
is defined, we can remove that first #if guard.

Suggested-by: Arnd Bergmann 
Signed-off-by: Ahmad Fatoum 
Acked-by: Dmitry Baryshkov 
Signed-off-by: Mike Snitzer

dm crypt: Spelling s/cihper/cipher/

2021-02-03T15:10:05+00:00

Fix a misspelling of "cipher".

Signed-off-by: Geert Uytterhoeven 
Signed-off-by: Mike Snitzer

dm crypt: fix copy and paste bug in crypt_alloc_req_aead

2021-01-21T20:06:44+00:00

In commit d68b29584c25 ("dm crypt: use GFP_ATOMIC when allocating
crypto requests from softirq") code was incorrectly copy and pasted
from crypt_alloc_req_skcipher()'s crypto request allocation code to
crypt_alloc_req_aead(). It is OK from runtime perspective as both
simple encryption request pointer and AEAD request pointer are part of
a union, but may confuse code reviewers.

Fixes: d68b29584c25 ("dm crypt: use GFP_ATOMIC when allocating crypto requests from softirq")
Cc: stable@vger.kernel.org # v5.9+
Reported-by: Pavel Machek 
Signed-off-by: Ignat Korchagin 
Signed-off-by: Mike Snitzer

dm crypt: defer decryption to a tasklet if interrupts disabled

2021-01-14T14:54:37+00:00

On some specific hardware on early boot we occasionally get:

[ 1193.920255][    T0] BUG: sleeping function called from invalid context at mm/mempool.c:381
[ 1193.936616][    T0] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/69
[ 1193.953233][    T0] no locks held by swapper/69/0.
[ 1193.965871][    T0] irq event stamp: 575062
[ 1193.977724][    T0] hardirqs last  enabled at (575061): [] tick_nohz_idle_exit+0xe2/0x3e0
[ 1194.002762][    T0] hardirqs last disabled at (575062): [] flush_smp_call_function_from_idle+0x4f/0x80
[ 1194.029035][    T0] softirqs last  enabled at (575050): [] asm_call_irq_on_stack+0x12/0x20
[ 1194.054227][    T0] softirqs last disabled at (575043): [] asm_call_irq_on_stack+0x12/0x20
[ 1194.079389][    T0] CPU: 69 PID: 0 Comm: swapper/69 Not tainted 5.10.6-cloudflare-kasan-2021.1.4-dev #1
[ 1194.104103][    T0] Hardware name: NULL R162-Z12-CD/MZ12-HD4-CD, BIOS R10 06/04/2020
[ 1194.119591][    T0] Call Trace:
[ 1194.130233][    T0]  dump_stack+0x9a/0xcc
[ 1194.141617][    T0]  ___might_sleep.cold+0x180/0x1b0
[ 1194.153825][    T0]  mempool_alloc+0x16b/0x300
[ 1194.165313][    T0]  ? remove_element+0x160/0x160
[ 1194.176961][    T0]  ? blk_mq_end_request+0x4b/0x490
[ 1194.188778][    T0]  crypt_convert+0x27f6/0x45f0 [dm_crypt]
[ 1194.201024][    T0]  ? rcu_read_lock_sched_held+0x3f/0x70
[ 1194.212906][    T0]  ? module_assert_mutex_or_preempt+0x3e/0x70
[ 1194.225318][    T0]  ? __module_address.part.0+0x1b/0x3a0
[ 1194.237212][    T0]  ? is_kernel_percpu_address+0x5b/0x190
[ 1194.249238][    T0]  ? crypt_iv_tcw_ctr+0x4a0/0x4a0 [dm_crypt]
[ 1194.261593][    T0]  ? is_module_address+0x25/0x40
[ 1194.272905][    T0]  ? static_obj+0x8a/0xc0
[ 1194.283582][    T0]  ? lockdep_init_map_waits+0x26a/0x700
[ 1194.295570][    T0]  ? __raw_spin_lock_init+0x39/0x110
[ 1194.307330][    T0]  kcryptd_crypt_read_convert+0x31c/0x560 [dm_crypt]
[ 1194.320496][    T0]  ? kcryptd_queue_crypt+0x1be/0x380 [dm_crypt]
[ 1194.333203][    T0]  blk_update_request+0x6d7/0x1500
[ 1194.344841][    T0]  ? blk_mq_trigger_softirq+0x190/0x190
[ 1194.356831][    T0]  blk_mq_end_request+0x4b/0x490
[ 1194.367994][    T0]  ? blk_mq_trigger_softirq+0x190/0x190
[ 1194.379693][    T0]  flush_smp_call_function_queue+0x24b/0x560
[ 1194.391847][    T0]  flush_smp_call_function_from_idle+0x59/0x80
[ 1194.403969][    T0]  do_idle+0x287/0x450
[ 1194.413891][    T0]  ? arch_cpu_idle_exit+0x40/0x40
[ 1194.424716][    T0]  ? lockdep_hardirqs_on_prepare+0x286/0x3f0
[ 1194.436399][    T0]  ? _raw_spin_unlock_irqrestore+0x39/0x40
[ 1194.447759][    T0]  cpu_startup_entry+0x19/0x20
[ 1194.458038][    T0]  secondary_startup_64_no_verify+0xb0/0xbb

IO completion can be queued to a different CPU by the block subsystem as a "call
single function/data". The CPU may run these routines from the idle task, but it
does so with interrupts disabled.

It is not a good idea to do decryption with irqs disabled even in an idle task
context, so just defer it to a tasklet (as is done with requests from hard irqs).

Fixes: 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues")
Cc: stable@vger.kernel.org # v5.9+
Signed-off-by: Ignat Korchagin 
Signed-off-by: Mike Snitzer