On 2011-09-30 07:33, Christoph Hellwig wrote: > On Fri, Sep 09, 2011 at 10:58:01AM +0200, Jens Axboe wrote: >>> - handling of REQ_FUA / REQ_FLUSH requests is completely broken. >>> There is a weird barrier flag to mtip_hw_submit_io which set the >>> hwardware FUA bit if the FLUSH bit is set on a request. >>> Please take a look at how this should be handled, the >>> Documentation/block/writeback_cache_control.txt file is the canonical >>> resource. Implementing your driver at the make_request layer >>> unfortunately means you will have to do all the hard work yourself. >> >> I noticed both of these flush/fua problems too and have fixed them up. > > I sitll can't find anything doing that in your tree while all kinds of > other patches are in. In fact I can't find a place that sends > ATA_CMD_FLUSH/ATA_CMD_FLUSH_EXT commands, not the required queue > draining for it. > > And this stuff really makes me nervous - we get a driver for a new, > expensive high end device and there seems absolutely no concern for > data integrity, or testing of it. I'm away from home, so changes have been coming in through the laptop. But don't worry about the driver, it's sort-of in a staging position at the moment. Before Micron has resolved the issues around queueing etc, it's not going to be merged into mainline. > Or does the device not even have a volatile cache at all, and we could > just remove the FUA code? In this case it should be clearly documented > in the driver. See reply from Micron folks, there's no write back cache currently. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
