From 0731de0dd95b251ed6cfb5f132486e52357fce53 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 14 Dec 2015 15:34:15 -0800 Subject: [PATCH] libnvdimm, pfn: move 'memory mode' indication to sysfs 'Memory mode' is defined as the capability of a DAX mapping to be the source/target of DMA and other "direct I/O" scenarios. While it currently requires allocating 'struct page' for each page frame of persistent memory in the namespace it will not always be the case. Work continues on reducing the kernel's dependency on 'struct page'. Let's not maintain a suffix that is expected to lose meaning over time. In other words a future 'raw mode' pmem namespace may be as capable as today's 'memory mode' namespace. Undo the encoding of the mode in the device name and leave it to other tooling to determine the mode of the namespace from its attributes. Reported-by: Matthew Wilcox Signed-off-by: Dan Williams --- drivers/nvdimm/namespace_devs.c | 41 ++++++++++++++++++++++----------- 1 file changed, 28 insertions(+), 13 deletions(-) diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c index ea8dd0cb28ca..ee6dee41155a 100644 --- a/drivers/nvdimm/namespace_devs.c +++ b/drivers/nvdimm/namespace_devs.c @@ -104,20 +104,10 @@ const char *nvdimm_namespace_disk_name(struct nd_namespace_common *ndns, struct nd_region *nd_region = to_nd_region(ndns->dev.parent); const char *suffix = NULL; - if (ndns->claim) { - if (is_nd_btt(ndns->claim)) - suffix = "s"; - else if (is_nd_pfn(ndns->claim)) - suffix = "m"; - else - dev_WARN_ONCE(&ndns->dev, 1, - "unknown claim type by %s\n", - dev_name(ndns->claim)); - } + if (ndns->claim && is_nd_btt(ndns->claim)) + suffix = "s"; if (is_namespace_pmem(&ndns->dev) || is_namespace_io(&ndns->dev)) { - if (!suffix && pmem_should_map_pages(&ndns->dev)) - suffix = "m"; sprintf(name, "pmem%d%s", nd_region->id, suffix ? suffix : ""); } else if (is_namespace_blk(&ndns->dev)) { struct nd_namespace_blk *nsblk; @@ -1224,6 +1214,29 @@ static ssize_t holder_show(struct device *dev, } static DEVICE_ATTR_RO(holder); +static ssize_t mode_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct nd_namespace_common *ndns = to_ndns(dev); + struct device *claim; + char *mode; + ssize_t rc; + + device_lock(dev); + claim = ndns->claim; + if (pmem_should_map_pages(dev) || (claim && is_nd_pfn(claim))) + mode = "memory"; + else if (claim && is_nd_btt(claim)) + mode = "safe"; + else + mode = "raw"; + rc = sprintf(buf, "%s\n", mode); + device_unlock(dev); + + return rc; +} +static DEVICE_ATTR_RO(mode); + static ssize_t force_raw_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { @@ -1247,6 +1260,7 @@ static DEVICE_ATTR_RW(force_raw); static struct attribute *nd_namespace_attributes[] = { &dev_attr_nstype.attr, &dev_attr_size.attr, + &dev_attr_mode.attr, &dev_attr_uuid.attr, &dev_attr_holder.attr, &dev_attr_resource.attr, @@ -1280,7 +1294,8 @@ static umode_t namespace_visible(struct kobject *kobj, if (a == &dev_attr_nstype.attr || a == &dev_attr_size.attr || a == &dev_attr_holder.attr - || a == &dev_attr_force_raw.attr) + || a == &dev_attr_force_raw.attr + || a == &dev_attr_mode.attr) return a->mode; return 0; -- 2.20.1