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2025-02-03dm-crypt: Document integrity_key_size option.Milan Broz
This patch adds documentation for new option introduced in commit 4441686b24a1 ("dm-crypt: Allow to specify the integrity key size as option"). Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-09-27Merge tag 'for-6.12/dm-changes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm Pull device mapper updates from Mikulas Patocka: - Misc VDO fixes - Remove unused declarations dm_get_rq_mapinfo() and dm_zone_map_bio() - Dm-delay: Improve kernel documentation - Dm-crypt: Allow to specify the integrity key size as an option - Dm-bufio: Remove pointless NULL check - Small code cleanups: Use ERR_CAST; remove unlikely() around IS_ERR; use __assign_bit - Dm-integrity: Fix gcc 5 warning; convert comma to semicolon; fix smatch warning - Dm-integrity: Support recalculation in the 'I' mode - Revert "dm: requeue IO if mapping table not yet available" - Dm-crypt: Small refactoring to make the code more readable - Dm-cache: Remove pointless error check - Dm: Fix spelling errors - Dm-verity: Restart or panic on an I/O error if restart or panic was requested - Dm-verity: Fallback to platform keyring also if key in trusted keyring is rejected * tag 'for-6.12/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (26 commits) dm verity: fallback to platform keyring also if key in trusted keyring is rejected dm-verity: restart or panic on an I/O error dm: fix spelling errors dm-cache: remove pointless error check dm vdo: handle unaligned discards correctly dm vdo indexer: Convert comma to semicolon dm-crypt: Use common error handling code in crypt_set_keyring_key() dm-crypt: Use up_read() together with key_put() only once in crypt_set_keyring_key() Revert "dm: requeue IO if mapping table not yet available" dm-integrity: check mac_size against HASH_MAX_DIGESTSIZE in sb_mac() dm-integrity: support recalculation in the 'I' mode dm integrity: Convert comma to semicolon dm integrity: fix gcc 5 warning dm: Make use of __assign_bit() API dm integrity: Remove extra unlikely helper dm: Convert to use ERR_CAST() dm bufio: Remove NULL check of list_entry() dm-crypt: Allow to specify the integrity key size as option dm: Remove unused declaration and empty definition "dm_zone_map_bio" dm delay: enhance kernel documentation ...
2024-08-21dm-crypt: Allow to specify the integrity key size as optionIngo Franzki
For the MAC based integrity operation, the integrity key size (i.e. key_mac_size) is currently set to the digest size of the used digest. For wrapped key HMAC algorithms, the key size is independent of the cryptographic key size. So there is no known size of the mac key in such cases. The desired key size can optionally be specified as argument when the dm-crypt device is configured via 'integrity_key_size:%u'. If no integrity_key_size argument is specified, the mac key size is still set to the digest size, as before. Increase version number to 1.28.0 so that support for the new argument can be detected by user space (i.e. cryptsetup). Signed-off-by: Ingo Franzki <ifranzki@linux.ibm.com> Reviewed-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
2024-08-13Documentation: dm-crypt.rst warning + error fixDaniel Yang
While building kernel documention using make htmldocs command, I was getting unexpected indentation error. Single description was given for two module parameters with wrong indentation. So, I corrected the indentation of both parameters and the description. Signed-off-by: Shibu kumar <shibukumar.bit@gmail.com> Signed-off-by: Daniel Yang <danielyangkang@gmail.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: 0d815e3400e6 ("dm-crypt: limit the size of encryption requests")
2024-08-07docs: dm-crypt: Removal of unexpected indentation errorShibu Kumar
Add the required indentation to fix this docs build error: Documentation/admin-guide/device-mapper/dm-crypt.rst:167: ERROR: Unexpected indentation. Also split the documentation for read and write into separate blocks. Signed-off-by: Shibu kumar shibukumar.bit@gmail.com [jc: rewrote changelog] Signed-off-by: Jonathan Corbet <corbet@lwn.net> Link: https://lore.kernel.org/r/20240803183306.32425-1-shibukumar.bit@gmail.com
2024-07-10dm-crypt: limit the size of encryption requestsMikulas Patocka
There was a performance regression reported where dm-crypt would perform worse on new kernels than on old kernels. The reason is that the old kernels split the bios to NVMe request size (that is usually 65536 or 131072 bytes) and the new kernels pass the big bios through dm-crypt and split them underneath. If a big 1MiB bio is passed to dm-crypt, dm-crypt processes it on a single core without parallelization and this is what causes the performance degradation. This commit introduces new tunable variables /sys/module/dm_crypt/parameters/max_read_size and /sys/module/dm_crypt/parameters/max_write_size that specify the maximum bio size for dm-crypt. Bios larger than this value are split, so that they can be encrypted in parallel by multiple cores. If these variables are '0', a default 131072 is used. Splitting bios may cause performance regressions in other workloads - if this happens, the user should increase the value in max_read_size and max_write_size variables. max_read_size: 128k 2399MiB/s 256k 2368MiB/s 512k 1986MiB/s 1024 1790MiB/s max_write_size: 128k 1712MiB/s 256k 1651MiB/s 512k 1537MiB/s 1024k 1332MiB/s Note that if you run dm-crypt inside a virtual machine, you may need to do "echo numa >/sys/module/workqueue/parameters/default_affinity_scope" to improve performance. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Tested-by: Laurence Oberman <loberman@redhat.com>
2024-04-16dm-crypt: add the optional "high_priority" flagMikulas Patocka
When WQ_HIGHPRI was used for the dm-crypt kcryptd workqueue it was reported that dm-crypt performs badly when the system is loaded[1]. Because of reports of audio skipping, dm-crypt stopped using WQ_HIGHPRI with commit f612b2132db5 (Revert "dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues"). But it has since been determined that WQ_HIGHPRI provides improved performance (with reduced latency) for highend systems with much more resources than those laptop/desktop users which suffered from the use of WQ_HIGHPRI. As such, add an option "high_priority" that allows the use of WQ_HIGHPRI for dm-crypt's workqueues and also sets the write_thread to nice level MIN_NICE (-20). This commit makes it optional, so that normal users won't be harmed by it. [1] https://listman.redhat.com/archives/dm-devel/2023-February/053410.html Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2021-02-03dm crypt: support using trusted keysAhmad Fatoum
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 <a.fatoum@pengutronix.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-12-08Documentation: fix typos found in admin-guide subdirectoryAndrew Klychkov
Fixed twelve typos in cppc_sysfs.rst, binderfs.rst, paride.rst, zram.rst, bug-hunting.rst, introduction.rst, usage.rst, dm-crypt.rst Signed-off-by: Andrew Klychkov <andrew.a.klychkov@gmail.com> Reviewed-by: Jonathan Corbet <corbet@lwn.net> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lore.kernel.org/r/20201204070235.GA48631@spblnx124.lan Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-09-22dm crypt: document encrypted keyring key optionMilan Broz
Commit 27f5411a718c4 ("dm crypt: support using encrypted keys") introduced support for encrypted keyring type. Fix documentation in admin guide to mention this type. Fixes: 27f5411a718c4 ("dm crypt: support using encrypted keys") Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2020-09-22dm crypt: document new no_workqueue flagsMilan Broz
Commit 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues") introduced new dm-crypt 'no_read_workqueue' and 'no_write_workqueue' flags. Add documentation to admin guide for them. Fixes: 39d42fa96ba1 ("dm crypt: add flags to optionally bypass kcryptd workqueues") Signed-off-by: Milan Broz <gmazyland@gmail.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2019-07-15docs: device-mapper: move it to the admin-guideMauro Carvalho Chehab
The DM support describes lots of aspects related to mapped disk partitions from the userspace PoV. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>