On Wed, Jun 14, 2017 at 3:46 AM, Jan Kara <jack@xxxxxxx> wrote: > On Fri 09-06-17 13:24:56, Dan Williams wrote: >> Some platforms arrange for cpu caches to be flushed on power-fail. On >> those platforms there is no requirement that the kernel track and flush >> potentially dirty cache lines. Given that we still insert entries into >> the radix for locking purposes this patch only disables the cache flush >> loop, not the dirty tracking. >> >> Userspace can override the default cache setting via the block device >> queue "write_cache" attribute in sysfs. >> >> Cc: Jan Kara <jack@xxxxxxx> >> Cc: Jeff Moyer <jmoyer@xxxxxxxxxx> >> Cc: Christoph Hellwig <hch@xxxxxx> >> Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx> >> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> >> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> > > ... > >> - dax_flush(dax_dev, pgoff, kaddr, size); >> + if (test_bit(QUEUE_FLAG_WC, &bdev->bd_queue->queue_flags)) >> + dax_flush(dax_dev, pgoff, kaddr, size); > > IMHO the check belongs into dax_flush() similarly as blkdev_issue_flush() > takes silently handles whether the flush is actually needed or not. Looks good, will do.
