[2.2.7] zvol: Implement zvol threading as a Property

[ixhamza]

Currently, zvol threading can be switched through the zvol_request_sync module parameter system-wide. By making it a zvol property, zvol threading can be switched per zvol.

Reviewed-by: Tony Hutter [email protected]
Reviewed-by: Brian Behlendorf [email protected]
Reviewed-by: Alexander Motin [email protected]
Signed-off-by: Ameer Hamza [email protected]
Closes #15409
Fixes: #16498

Motivation and Context

Description

How Has This Been Tested?

• CI Testing.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.