On Thu, Jun 30, 2011 at 03:12:46PM +0200, Arnd Bergmann wrote:
I think this looks good enough to merge into the linux-mmc tree, the code is clean and the benefits are clear.
Acked-by: Arnd Bergmann arnd@arndb.de
One logical follow-up as both a cleanup and performance optimization would be to get rid of the mmc_queue_thread completely. When mmc_blk_issue_rq() is non-blocking always, you can call it directly from the mmc_request() function, instead of waking up another thread to do it for you.
It isn't anywhere near that - because you need to wait for the request to complete, then analyze the results and if there has been an error, send more commands and wait for their response.
To do all that in an asynchronous fashion will just create a mess of small little functions with hard to understand code. It's far better to do all that in a clear procedural way in a thread.
We've been here before - with PCMCIA's card insertion code, where you have to go through a sequence of events (insert, power up, reset, etc). The PCMCIA code used to have a collection of small functions to do each step, one chained after the other in a state machine fashion. The result was horrid. That's exactly what you'll end up with here.
Threads have their place, and this is one of them.