Hi Latency in do_read_onechip (was Re: Bottom halves being disabled)

[Linh Dang]

Hi David,

On our system, we have some slow AMD nor flash. The line

	map_copy_from(map, buf, adr, len);

in do_read_onechip (in cfi_cmdset_0002.c) is called while holding a
spin_lock (chip->mutex). This triggers 450usec non-preemptible periods
on our system.

1. Is there any plan to fix this?
2. Is it safe to replace the spin_lock with a semaphore?
3. while mtd has to lock softirq?

Thanx

-- 
Linh Dang