[9fans] page fault with lock held

[Sam <sah@softcardsystems.com>]

Hello 9fans,

I'm testing my AoE driver and have hit something curious.

On devaoe.c read, after getting the sectors from the
remote disk and when trying to copy the data to the
user process using memmove, I get a write page fault.
At the time, I happen to be holding a spinlock over
the device structure, which causes both
port/fault.c:/^fault/ and port/fault.c/^seg/ (via qlock)
to squawk at me about up->nlocks.ref > 0.

The user address in question is 7fffaedc.  Firstly, does
this address seem appropriate and secondly, is dropping
the spinlock during the memmove appropriate?

All signs point to yes, but I'd like some reassurance.

Cheers,

Sam