From 546eb0317cfa3c4f9e1d9ab892766d65d7f78fad Mon Sep 17 00:00:00 2001 From: Ross Zwisler Date: Wed, 6 Jun 2018 10:45:15 -0600 Subject: libnvdimm, pmem: Do not flush power-fail protected CPU caches This commit: 5fdf8e5ba566 ("libnvdimm: re-enable deep flush for pmem devices via fsync()") intended to make sure that deep flush was always available even on platforms which support a power-fail protected CPU cache. An unintended side effect of this change was that we also lost the ability to skip flushing CPU caches on those power-fail protected CPU cache. Fix this by skipping the low level cache flushing in dax_flush() if we have CPU caches which are power-fail protected. The user can still override this behavior by manually setting the write_cache state of a namespace. See libndctl's ndctl_namespace_write_cache_is_enabled(), ndctl_namespace_enable_write_cache() and ndctl_namespace_disable_write_cache() functions. Cc: Fixes: 5fdf8e5ba566 ("libnvdimm: re-enable deep flush for pmem devices via fsync()") Signed-off-by: Ross Zwisler Signed-off-by: Dan Williams --- drivers/nvdimm/region_devs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'drivers/nvdimm') diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c index a612be6f019d..ec3543b83330 100644 --- a/drivers/nvdimm/region_devs.c +++ b/drivers/nvdimm/region_devs.c @@ -1132,7 +1132,8 @@ EXPORT_SYMBOL_GPL(nvdimm_has_flush); int nvdimm_has_cache(struct nd_region *nd_region) { - return is_nd_pmem(&nd_region->dev); + return is_nd_pmem(&nd_region->dev) && + !test_bit(ND_REGION_PERSIST_CACHE, &nd_region->flags); } EXPORT_SYMBOL_GPL(nvdimm_has_cache); -- cgit v1.2.3