In preparation for a facility that enables dax regions to be sub-divided, introduce infrastructure to track and allocate region capacity.
The new dax_region/available_size attribute is only enabled for volatile hmem devices, not pmem devices that are defined by nvdimm namespace boundaries. This is per Jeff's feedback the last time dynamic device-dax capacity allocation support was discussed.
Link: https://lore.kernel.org/linux-nvdimm/x49shpp3zn8.fsf@segfault.boston.devel.r... Cc: Vishal Verma vishal.l.verma@intel.com Signed-off-by: Dan Williams dan.j.williams@intel.com --- drivers/dax/bus.c | 120 +++++++++++++++++++++++++++++++++++++++++---- drivers/dax/bus.h | 7 ++- drivers/dax/dax-private.h | 2 - drivers/dax/hmem/hmem.c | 7 +-- drivers/dax/pmem/core.c | 8 +-- 5 files changed, 121 insertions(+), 23 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c index 96bd64ba95a5..0a48ce378686 100644 --- a/drivers/dax/bus.c +++ b/drivers/dax/bus.c @@ -130,6 +130,11 @@ ATTRIBUTE_GROUPS(dax_drv);
static int dax_bus_match(struct device *dev, struct device_driver *drv);
+static bool is_static(struct dax_region *dax_region) +{ + return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0; +} + static struct bus_type dax_bus_type = { .name = "dax", .uevent = dax_bus_uevent, @@ -185,7 +190,48 @@ static ssize_t align_show(struct device *dev, } static DEVICE_ATTR_RO(align);
+#define for_each_dax_region_resource(dax_region, res) \ + for (res = (dax_region)->res.child; res; res = res->sibling) + +static unsigned long long dax_region_avail_size(struct dax_region *dax_region) +{ + resource_size_t size = resource_size(&dax_region->res); + struct resource *res; + + device_lock_assert(dax_region->dev); + + for_each_dax_region_resource(dax_region, res) + size -= resource_size(res); + return size; +} + +static ssize_t available_size_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct dax_region *dax_region = dev_get_drvdata(dev); + unsigned long long size; + + device_lock(dev); + size = dax_region_avail_size(dax_region); + device_unlock(dev); + + return sprintf(buf, "%llu\n", size); +} +static DEVICE_ATTR_RO(available_size); + +static umode_t dax_region_visible(struct kobject *kobj, struct attribute *a, + int n) +{ + struct device *dev = container_of(kobj, struct device, kobj); + struct dax_region *dax_region = dev_get_drvdata(dev); + + if (is_static(dax_region) && a == &dev_attr_available_size.attr) + return 0; + return a->mode; +} + static struct attribute *dax_region_attributes[] = { + &dev_attr_available_size.attr, &dev_attr_region_size.attr, &dev_attr_align.attr, &dev_attr_id.attr, @@ -195,6 +241,7 @@ static struct attribute *dax_region_attributes[] = { static const struct attribute_group dax_region_attribute_group = { .name = "dax_region", .attrs = dax_region_attributes, + .is_visible = dax_region_visible, };
static const struct attribute_group *dax_region_attribute_groups[] = { @@ -226,7 +273,8 @@ static void dax_region_unregister(void *region) }
struct dax_region *alloc_dax_region(struct device *parent, int region_id, - struct resource *res, int target_node, unsigned int align) + struct resource *res, int target_node, unsigned int align, + unsigned long flags) { struct dax_region *dax_region;
@@ -249,12 +297,17 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id, return NULL;
dev_set_drvdata(parent, dax_region); - memcpy(&dax_region->res, res, sizeof(*res)); kref_init(&dax_region->kref); dax_region->id = region_id; dax_region->align = align; dax_region->dev = parent; dax_region->target_node = target_node; + dax_region->res = (struct resource) { + .start = res->start, + .end = res->end, + .flags = IORESOURCE_MEM | flags, + }; + if (sysfs_create_groups(&parent->kobj, dax_region_attribute_groups)) { kfree(dax_region); return NULL; @@ -267,6 +320,32 @@ struct dax_region *alloc_dax_region(struct device *parent, int region_id, } EXPORT_SYMBOL_GPL(alloc_dax_region);
+static int alloc_dev_dax_range(struct dev_dax *dev_dax, resource_size_t size) +{ + struct dax_region *dax_region = dev_dax->region; + struct resource *res = &dax_region->res; + struct device *dev = &dev_dax->dev; + struct resource *alloc; + + device_lock_assert(dax_region->dev); + + /* TODO: handle multiple allocations per region */ + if (res->child) + return -ENOMEM; + + alloc = __request_region(res, res->start, size, dev_name(dev), 0); + + if (!alloc) + return -ENOMEM; + + dev_dax->range = (struct range) { + .start = alloc->start, + .end = alloc->end, + }; + + return 0; +} + static ssize_t size_show(struct device *dev, struct device_attribute *attr, char *buf) { @@ -361,6 +440,15 @@ void kill_dev_dax(struct dev_dax *dev_dax) } EXPORT_SYMBOL_GPL(kill_dev_dax);
+static void free_dev_dax_range(struct dev_dax *dev_dax) +{ + struct dax_region *dax_region = dev_dax->region; + struct range *range = &dev_dax->range; + + device_lock_assert(dax_region->dev); + __release_region(&dax_region->res, range->start, range_len(range)); +} + static void dev_dax_release(struct device *dev) { struct dev_dax *dev_dax = to_dev_dax(dev); @@ -385,6 +473,7 @@ static void unregister_dev_dax(void *dev) dev_dbg(dev, "%s\n", __func__);
kill_dev_dax(dev_dax); + free_dev_dax_range(dev_dax); device_del(dev); put_device(dev); } @@ -397,7 +486,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) struct dev_dax *dev_dax; struct inode *inode; struct device *dev; - int rc = -ENOMEM; + int rc;
if (data->id < 0) return ERR_PTR(-EINVAL); @@ -406,11 +495,25 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) if (!dev_dax) return ERR_PTR(-ENOMEM);
+ dev_dax->region = dax_region; + dev = &dev_dax->dev; + device_initialize(dev); + dev_set_name(dev, "dax%d.%d", dax_region->id, data->id); + + rc = alloc_dev_dax_range(dev_dax, data->size); + if (rc) + goto err_range; + if (data->pgmap) { + dev_WARN_ONCE(parent, !is_static(dax_region), + "custom dev_pagemap requires a static dax_region\n"); + dev_dax->pgmap = kmemdup(data->pgmap, sizeof(struct dev_pagemap), GFP_KERNEL); - if (!dev_dax->pgmap) + if (!dev_dax->pgmap) { + rc = -ENOMEM; goto err_pgmap; + } }
/* @@ -427,12 +530,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) kill_dax(dax_dev);
/* from here on we're committed to teardown via dev_dax_release() */ - dev = &dev_dax->dev; - device_initialize(dev); - dev_dax->dax_dev = dax_dev; - dev_dax->region = dax_region; - dev_dax->range = data->range; dev_dax->target_node = dax_region->target_node; kref_get(&dax_region->kref);
@@ -444,7 +542,6 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) dev->class = dax_class; dev->parent = parent; dev->type = &dev_dax_type; - dev_set_name(dev, "dax%d.%d", dax_region->id, data->id);
rc = device_add(dev); if (rc) { @@ -458,9 +555,12 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data) return ERR_PTR(rc);
return dev_dax; + err_alloc_dax: kfree(dev_dax->pgmap); err_pgmap: + free_dev_dax_range(dev_dax); +err_range: kfree(dev_dax);
return ERR_PTR(rc); diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h index 4aeb36da83a4..44592a8cac0f 100644 --- a/drivers/dax/bus.h +++ b/drivers/dax/bus.h @@ -10,8 +10,11 @@ struct resource; struct dax_device; struct dax_region; void dax_region_put(struct dax_region *dax_region); + +#define IORESOURCE_DAX_STATIC (1UL << 0) struct dax_region *alloc_dax_region(struct device *parent, int region_id, - struct resource *res, int target_node, unsigned int align); + struct resource *res, int target_node, unsigned int align, + unsigned long flags);
enum dev_dax_subsys { DEV_DAX_BUS = 0, /* zeroed dev_dax_data picks this by default */ @@ -22,7 +25,7 @@ struct dev_dax_data { struct dax_region *dax_region; struct dev_pagemap *pgmap; enum dev_dax_subsys subsys; - struct range range; + resource_size_t size; int id; };
diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h index 12a2dbc43b40..99b1273bb232 100644 --- a/drivers/dax/dax-private.h +++ b/drivers/dax/dax-private.h @@ -22,7 +22,7 @@ void dax_bus_exit(void); * @kref: to pin while other agents have a need to do lookups * @dev: parent device backing this region * @align: allocation and mapping alignment for child dax devices - * @res: physical address range of the region + * @res: resource tree to track instance allocations */ struct dax_region { int id; diff --git a/drivers/dax/hmem/hmem.c b/drivers/dax/hmem/hmem.c index af82d6ba820a..e7b64539e23e 100644 --- a/drivers/dax/hmem/hmem.c +++ b/drivers/dax/hmem/hmem.c @@ -20,17 +20,14 @@ static int dax_hmem_probe(struct platform_device *pdev)
mri = dev->platform_data; dax_region = alloc_dax_region(dev, pdev->id, res, mri->target_node, - PMD_SIZE); + PMD_SIZE, 0); if (!dax_region) return -ENOMEM;
data = (struct dev_dax_data) { .dax_region = dax_region, .id = 0, - .range = { - .start = res->start, - .end = res->end, - }, + .size = resource_size(res), }; dev_dax = devm_create_dev_dax(&data); if (IS_ERR(dev_dax)) diff --git a/drivers/dax/pmem/core.c b/drivers/dax/pmem/core.c index 4fa81d3d2f65..4fe700884338 100644 --- a/drivers/dax/pmem/core.c +++ b/drivers/dax/pmem/core.c @@ -54,7 +54,8 @@ struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys) memcpy(&res, &pgmap.res, sizeof(res)); res.start += offset; dax_region = alloc_dax_region(dev, region_id, &res, - nd_region->target_node, le32_to_cpu(pfn_sb->align)); + nd_region->target_node, le32_to_cpu(pfn_sb->align), + IORESOURCE_DAX_STATIC); if (!dax_region) return ERR_PTR(-ENOMEM);
@@ -63,10 +64,7 @@ struct dev_dax *__dax_pmem_probe(struct device *dev, enum dev_dax_subsys subsys) .id = id, .pgmap = &pgmap, .subsys = subsys, - .range = { - .start = res.start, - .end = res.end, - }, + .size = resource_size(&res), }; dev_dax = devm_create_dev_dax(&data);