Re: Correct use of ap->lock versus ap->host->lock ?

[Jeff Garzik <jeff@garzik.org>]

Jeff Garzik wrote:
> You need to perform your own LLD-specific locking analysis to see if it 
> is safe to do, e.g. __mv_stop_dma() rather than mv_stop_dma().

And speaking as the probable author of some of the code that takes a 
lock during EH in sata_mv....   reinforcing that the above quoted 
statement is true.

Generally I would put in a lock during EH around register or data 
manipulations that were locked elsewhere in the driver, thus 
guaranteeing such code is safe.

However, it may also be the case that such a lock during EH is 
unnecessary because command submission machinery is disabled.  I chose a 
path that potentially added more locking, but was much easier to verify 
correct.

	Jeff