[PATCH 2/2] libnvdimm: Export max available extent

The 'available_size' attribute showing the combined total of all unallocated space isn't always useful to know how large of a namespace a user may be able to allocate if the region is fragmented. This patch will export the largest extent of contiguous unallocated space that may be allocated to create a new namespace. Signed-off-by: Keith Busch <keith.busch(a)intel.com&gt; --- drivers/nvdimm/region_devs.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c index 8af483d7ef57..82aaf7d6488d 100644 --- a/drivers/nvdimm/region_devs.c +++ b/drivers/nvdimm/region_devs.c @@ -433,6 +433,21 @@ static ssize_t available_size_show(struct device *dev, } static DEVICE_ATTR_RO(available_size); +static ssize_t max_available_extent_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct nd_region *nd_region = to_nd_region(dev); + unsigned long long available = 0; + + nvdimm_bus_lock(dev); + wait_nvdimm_bus_probe_idle(dev); + available = nd_region_contiguous_max(nd_region); + nvdimm_bus_unlock(dev); + + return sprintf(buf, "%llu\n", available); +} +static DEVICE_ATTR_RO(max_available_extent); + static ssize_t init_namespaces_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -584,6 +599,7 @@ static struct attribute *nd_region_attributes[] = { &dev_attr_read_only.attr, &dev_attr_set_cookie.attr, &dev_attr_available_size.attr, + &dev_attr_max_available_extent.attr, &dev_attr_namespace_seed.attr, &dev_attr_init_namespaces.attr, &dev_attr_badblocks.attr, -- 2.14.3