sys/linux: update descriptions in dev_block.txt

[fellair]

A few things done here:

• Add new block device ioctls (and structs) related to encryption, added in 1ebd4a3c095c ("blk-crypto: add ioctls to create and prepare hardware-wrapped keys"):
  BLKCRYPTOIMPORTKEY
  BLKCRYPTOGENERATEKEY
  BLKCRYPTOPREPAREKEY
• Add and update new/missing syscalls' descriptions related to zoned block devices:
  BLKGETZONESZ
  BLKGETNRZONES
  BLKOPENZONE
  BLKCLOSEZONE
  BLKFINISHZONE
• Add a few other missing syscalls, such as BLKRASET.
• Fix some syscalls' directions (mostly, to 'inout').

Tested with make presubmit and local syzkaller instance with 'null_blk.zoned=1'. No descriptions were deleted, only modified.

P.S. To fully utilize zoned-related ioctls, we need to come up with a way to change /dev/nullb0 to zoned device and back.

[a-nogikh]

Thanks!

Regarding null_blk.zoned=1 - if we set it on syzbot, we won't test the code that needs null_blk.zoned=0, right? Is it somehow possible to somehow test both?

If not, I guess we could set null_blk.zoned=1 on some of our instances. now I've noticed #6089 you opened

[fellair]

v2:

• updated blk_crypto* structs per comments above; that includes work with output buffers holding lt_key_ptr and eph_key_ptr. I am certain that those keys, depending on mode, may have sensible lower limits when it come to key sizes. Still, I opted for a variable length to account for weird user inputs.

We still need to figure out how to:

• enable crypto ioctls properly. That implies device setup that has blk_crypto_profile initialized correctly - I will look into that.
• enable null_blk as zoned. As mentioned above and in all: modify device driver parameters during fuzzing #6089, simply enabling null_blk.zoned=1 on some instances may negatively affect coverage. However, if maintainers agree, I don't mind doing that. All I need is to know what instances to patch configs in.

[a-nogikh]

Thanks!
Shall we merge the PR now? Or did you want to include something else to this change set?

[fellair]

Thanks! Shall we merge the PR now? Or did you want to include something else to this change set?

Let's merge now, I'll figure out crypto ioctl issue separately, same goes for zoned null_blk. Thank you!