Mikulas Patocka c3ca015fab dax: remove the pmem_dax_ops->flush abstraction ... Commit abebfbe2f7 ("dm: add ->flush() dax operation support") is buggy. A DM device may be composed of multiple underlying devices and all of them need to be flushed. That commit just routes the flush request to the first device and ignores the other devices. It could be fixed by adding more complex logic to the device mapper. But there is only one implementation of the method pmem_dax_ops->flush - that is pmem_dax_flush() - and it calls arch_wb_cache_pmem(). Consequently, we don't need the pmem_dax_ops->flush abstraction at all, we can call arch_wb_cache_pmem() directly from dax_flush() because dax_dev->ops->flush can't ever reach anything different from arch_wb_cache_pmem(). It should be also pointed out that for some uses of persistent memory it is needed to flush only a very small amount of data (such as 1 cacheline), and it would be overkill if we go through that device mapper machinery for a single flushed cache line. Fix this by removing the pmem_dax_ops->flush abstraction and call arch_wb_cache_pmem() directly from dax_flush(). Also, remove the device mapper code that forwards the flushes. Fixes: abebfbe2f7 ("dm: add ->flush() dax operation support") Cc: stable@vger.kernel.org Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>		2017-09-11 11:00:55 -04:00
..
dax-private.h	Merge branch 'for-4.12/dax' into libnvdimm-for-next	2017-05-04 23:38:43 -07:00
dax.h	pmem: add dax_operations support	2017-04-19 15:14:35 -07:00
device-dax.h	device-dax: fix sysfs duplicate warnings	2017-07-18 17:49:14 -07:00
device.c	device-dax: fix sysfs duplicate warnings	2017-07-18 17:49:14 -07:00
Kconfig	device-dax: kill NR_DEV_DAX	2017-05-09 09:08:22 -07:00
Makefile	dax: refactor dax-fs into a generic provider of 'struct dax_device' instances	2017-04-12 21:59:14 -07:00
pmem.c	device-dax: fix sysfs duplicate warnings	2017-07-18 17:49:14 -07:00
super.c	dax: remove the pmem_dax_ops->flush abstraction	2017-09-11 11:00:55 -04:00