Re: [PATCH v7] mmc: support BKOPS feature for eMMC

[Adrian Hunter <adrian.hunter@intel.com>]

On 23/02/12 04:21, Jaehoon Chung wrote:
> On 02/22/2012 11:11 PM, Adrian Hunter wrote:
> 
>> On 20/01/12 08:48, Jaehoon Chung wrote:
>>> Enable eMMC background operations (BKOPS) feature.
>>>
>>> If URGENT_BKOPS is set after a response, note that BKOPS
>>> are required. After all I/O requests are finished, run
>>> BKOPS if required. Should read/write operations be requested
>>> during BKOPS, first issue HPI to interrupt the ongoing BKOPS
>>> and then service the request.
>>
>> You are leaving bkops running and releasing the host.  Won't
>> that cause problems for other entry points to mmc services
>> e.g. system suspend (cache control, sleep etc), ioctl, sysfs,
>> etc
> 
> I see. i will complement for your review.

Please cc me.

> Didn't you have the other comment?

Well, yes.  I also suggest:
	- don't use host->lock spin lock at all
	- claim the host in the caller not in
	mmc_start_bkops()

But the main issues are design issues not implementation.
i.e.
	- always run bkops at level 3 before doing any
	other requests - that requirement should probably
	be implemented in core rather than the block driver
	- do not release the host while bkops are running

And a new one:
	- how do you know that trim/discard/sanitize will not
	result in a need for bkops?