linux kernel - Constructor time IO in a device mapper implementation -

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i'm developing device mapper driver , wondering delays dues performing disk initialization in constructor context. there's fair amount of io done during initial setup - ranges of blocks clean out.

from looking on dm implementations appears work done synchronously in constructor. constructor shouldn't allowed return until operation done. don't know if that's idea or whether there's way make asynchronous until init time work done.

i thinking calls 'map' might deferred returning dm_io_requeue until operation completes. may seconds. i've not found docs or reference covers function set of target_type structure in dm. i've seen of dm drivers making use of of these function indirects. hints on there's details of methods or rules on can , can't done in constructor?


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