[dm-devel] How can I get my sector size (via queue_limits?) from a dm_target?

[Eric Wheeler]

Hello all,

dm_target->len gives me sector count, but I need to know the default 
sector size discovered by the blk stacking code without assuming 512b.

Now that I have the dm .iterate_devices callback defined and my 
queue_limits are sane by default, how can I get a pointer to the 
queue_limits structure for my device given a dm_target structure?

It looks like I should call dm_get_md_queue() after getting the md from 
dm_table_get_md(target->table), but dm_get_md_queue is not an exported 
symbol.

Also, is that value correct within the .ctr, or only after the .ctr 
returns?  If after, how can I hook in after limits are assigned but before 
.map gets called?  Otherwise stated, I would like to know the stacked 
queue_limits corrected for lower layers within the .ctr function.

Thanks for your help!

-Eric