Allow additional options to the cryptsetup

[jsirex]

Looks like it is NOT possible to provide additional options to the cryptsetup.

For example:

      --allow-discards
              Allow the use of discard (TRIM) requests for the device.  This option is only relevant for open action.  This is also not supported for LUKS2 devices with data integrity protection.

              WARNING: This command can have a negative security impact because it can make filesystem-level operations visible on the physical device. For example, information leaking filesystem type, used
              space, etc. may be extractable from the physical device if the discarded blocks can be located later. If in doubt, do not use it.

              A kernel version of 3.1 or later is needed. For earlier kernels, this option is ignored.

       --perf-same_cpu_crypt
              Perform  encryption using the same cpu that IO was submitted on.  The default is to use an unbound workqueue so that encryption work is automatically balanced between available CPUs.  This op‐
              tion is only relevant for open action.

              NOTE: This option is available only for low-level dm-crypt performance tuning, use only if you need a change to default dm-crypt behaviour. Needs kernel 4.0 or later.

       --perf-submit_from_crypt_cpus
              Disable offloading writes to a separate thread after encryption.  There are some situations where offloading write bios from the encryption threads to a single thread degrades performance sig‐
              nificantly.  The default is to offload write bios to the same thread.  This option is only relevant for open action.

              NOTE: This option is available only for low-level dm-crypt performance tuning, use only if you need a change to default dm-crypt behaviour. Needs kernel 4.0 or later.

       --perf-no_read_workqueue, --perf-no_write_workqueue
              Bypass dm-crypt internal workqueue and process read or write requests synchronously.  This option is only relevant for open action.

              NOTE: These options are available only for low-level dm-crypt performance tuning, use only if you need a change to default dm-crypt behaviour. Needs kernel 5.9 or later.

At least I unable to find the way to provide --perf-no_read_workqueue, --perf-no_write_workqueue

More about performance tuning: https://blog.cloudflare.com/speeding-up-linux-disk-encryption/

[felixfontein]

New options for specific parameters can be added, PRs are welcome. What will not be accepted is a general "additional parameters" option.