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authorDan Williams <dan.j.williams@intel.com>2020-10-14 02:50:24 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-14 04:38:28 +0300
commitfcffb6a1df921c81579e9c01f9caa281c3f991d5 (patch)
tree7cd611d81a69819e3b5b7f10ff3574acfde1fd76 /drivers/dax
parentc77f520db8ebed1ffdeb8a545526dc093365d972 (diff)
downloadlinux-fcffb6a1df921c81579e9c01f9caa281c3f991d5.tar.xz
device-dax: add resize support
Make the device-dax 'size' attribute writable to allow capacity to be split between multiple instances in a region. The intended consumers of this capability are users that want to split a scarce memory resource between device-dax and System-RAM access, or users that want to have multiple security domains for a large region. By default the hmem instance provider allocates an entire region to the first instance. The process of creating a new instance (assuming a region-id of 0) is find the region and trigger the 'create' attribute which yields an empty instance to configure. For example: cd /sys/bus/dax/devices echo dax0.0 > dax0.0/driver/unbind echo $new_size > dax0.0/size echo 1 > $(readlink -f dax0.0)../dax_region/create seed=$(cat $(readlink -f dax0.0)../dax_region/seed) echo $new_size > $seed/size echo dax0.0 > ../drivers/{device_dax,kmem}/bind echo dax0.1 > ../drivers/{device_dax,kmem}/bind Instances can be destroyed by: echo $device > $(readlink -f $device)../dax_region/delete Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: Brice Goglin <Brice.Goglin@inria.fr> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jia He <justin.he@arm.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Ard Biesheuvel <ardb@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: David Airlie <airlied@linux.ie> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hulk Robot <hulkci@huawei.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Jason Yan <yanaijie@huawei.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: "Jérôme Glisse" <jglisse@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: kernel test robot <lkp@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Rapoport <rppt@linux.ibm.com> Cc: Paul Mackerras <paulus@ozlabs.org> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/159643102625.4062302.7431838945566033852.stgit@dwillia2-desk3.amr.corp.intel.com Link: https://lkml.kernel.org/r/160106115239.30709.9850106928133493138.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/dax')
-rw-r--r--drivers/dax/bus.c161
1 files changed, 152 insertions, 9 deletions
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index dce9413a4394..53d07f2f1285 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -6,6 +6,7 @@
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/dax.h>
+#include <linux/io.h>
#include "dax-private.h"
#include "bus.h"
@@ -562,7 +563,8 @@ 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)
+static int alloc_dev_dax_range(struct dev_dax *dev_dax, u64 start,
+ resource_size_t size)
{
struct dax_region *dax_region = dev_dax->region;
struct resource *res = &dax_region->res;
@@ -580,12 +582,7 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, resource_size_t size)
return 0;
}
- /* TODO: handle multiple allocations per region */
- if (res->child)
- return -ENOMEM;
-
- alloc = __request_region(res, res->start, size, dev_name(dev), 0);
-
+ alloc = __request_region(res, start, size, dev_name(dev), 0);
if (!alloc)
return -ENOMEM;
@@ -597,6 +594,29 @@ static int alloc_dev_dax_range(struct dev_dax *dev_dax, resource_size_t size)
return 0;
}
+static int adjust_dev_dax_range(struct dev_dax *dev_dax, struct resource *res, resource_size_t size)
+{
+ struct dax_region *dax_region = dev_dax->region;
+ struct range *range = &dev_dax->range;
+ int rc = 0;
+
+ device_lock_assert(dax_region->dev);
+
+ if (size)
+ rc = adjust_resource(res, range->start, size);
+ else
+ __release_region(&dax_region->res, range->start, range_len(range));
+ if (rc)
+ return rc;
+
+ dev_dax->range = (struct range) {
+ .start = range->start,
+ .end = range->start + size - 1,
+ };
+
+ return 0;
+}
+
static ssize_t size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -605,7 +625,127 @@ static ssize_t size_show(struct device *dev,
return sprintf(buf, "%llu\n", size);
}
-static DEVICE_ATTR_RO(size);
+
+static bool alloc_is_aligned(struct dax_region *dax_region,
+ resource_size_t size)
+{
+ /*
+ * The minimum mapping granularity for a device instance is a
+ * single subsection, unless the arch says otherwise.
+ */
+ return IS_ALIGNED(size, max_t(unsigned long, dax_region->align,
+ memremap_compat_align()));
+}
+
+static int dev_dax_shrink(struct dev_dax *dev_dax, resource_size_t size)
+{
+ struct dax_region *dax_region = dev_dax->region;
+ struct range *range = &dev_dax->range;
+ struct resource *res, *adjust = NULL;
+ struct device *dev = &dev_dax->dev;
+
+ for_each_dax_region_resource(dax_region, res)
+ if (strcmp(res->name, dev_name(dev)) == 0
+ && res->start == range->start) {
+ adjust = res;
+ break;
+ }
+
+ if (dev_WARN_ONCE(dev, !adjust, "failed to find matching resource\n"))
+ return -ENXIO;
+ return adjust_dev_dax_range(dev_dax, adjust, size);
+}
+
+static ssize_t dev_dax_resize(struct dax_region *dax_region,
+ struct dev_dax *dev_dax, resource_size_t size)
+{
+ resource_size_t avail = dax_region_avail_size(dax_region), to_alloc;
+ resource_size_t dev_size = range_len(&dev_dax->range);
+ struct resource *region_res = &dax_region->res;
+ struct device *dev = &dev_dax->dev;
+ const char *name = dev_name(dev);
+ struct resource *res, *first;
+
+ if (dev->driver)
+ return -EBUSY;
+ if (size == dev_size)
+ return 0;
+ if (size > dev_size && size - dev_size > avail)
+ return -ENOSPC;
+ if (size < dev_size)
+ return dev_dax_shrink(dev_dax, size);
+
+ to_alloc = size - dev_size;
+ if (dev_WARN_ONCE(dev, !alloc_is_aligned(dax_region, to_alloc),
+ "resize of %pa misaligned\n", &to_alloc))
+ return -ENXIO;
+
+ /*
+ * Expand the device into the unused portion of the region. This
+ * may involve adjusting the end of an existing resource, or
+ * allocating a new resource.
+ */
+ first = region_res->child;
+ if (!first)
+ return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
+ for (res = first; to_alloc && res; res = res->sibling) {
+ struct resource *next = res->sibling;
+ resource_size_t free;
+
+ /* space at the beginning of the region */
+ free = 0;
+ if (res == first && res->start > dax_region->res.start)
+ free = res->start - dax_region->res.start;
+ if (free >= to_alloc && dev_size == 0)
+ return alloc_dev_dax_range(dev_dax, dax_region->res.start, to_alloc);
+
+ free = 0;
+ /* space between allocations */
+ if (next && next->start > res->end + 1)
+ free = next->start - res->end + 1;
+
+ /* space at the end of the region */
+ if (free < to_alloc && !next && res->end < region_res->end)
+ free = region_res->end - res->end;
+
+ if (free >= to_alloc && strcmp(name, res->name) == 0)
+ return adjust_dev_dax_range(dev_dax, res, resource_size(res) + to_alloc);
+ else if (free >= to_alloc && dev_size == 0)
+ return alloc_dev_dax_range(dev_dax, res->end + 1, to_alloc);
+ }
+ return -ENOSPC;
+}
+
+static ssize_t size_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ ssize_t rc;
+ unsigned long long val;
+ struct dev_dax *dev_dax = to_dev_dax(dev);
+ struct dax_region *dax_region = dev_dax->region;
+
+ rc = kstrtoull(buf, 0, &val);
+ if (rc)
+ return rc;
+
+ if (!alloc_is_aligned(dax_region, val)) {
+ dev_dbg(dev, "%s: size: %lld misaligned\n", __func__, val);
+ return -EINVAL;
+ }
+
+ device_lock(dax_region->dev);
+ if (!dax_region->dev->driver) {
+ device_unlock(dax_region->dev);
+ return -ENXIO;
+ }
+ device_lock(dev);
+ rc = dev_dax_resize(dax_region, dev_dax, val);
+ device_unlock(dev);
+ device_unlock(dax_region->dev);
+
+ return rc == 0 ? len : rc;
+}
+static DEVICE_ATTR_RW(size);
static int dev_dax_target_node(struct dev_dax *dev_dax)
{
@@ -654,11 +794,14 @@ static umode_t dev_dax_visible(struct kobject *kobj, struct attribute *a, int n)
{
struct device *dev = container_of(kobj, struct device, kobj);
struct dev_dax *dev_dax = to_dev_dax(dev);
+ struct dax_region *dax_region = dev_dax->region;
if (a == &dev_attr_target_node.attr && dev_dax_target_node(dev_dax) < 0)
return 0;
if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
return 0;
+ if (a == &dev_attr_size.attr && is_static(dax_region))
+ return 0444;
return a->mode;
}
@@ -739,7 +882,7 @@ struct dev_dax *devm_create_dev_dax(struct dev_dax_data *data)
device_initialize(dev);
dev_set_name(dev, "dax%d.%d", dax_region->id, dev_dax->id);
- rc = alloc_dev_dax_range(dev_dax, data->size);
+ rc = alloc_dev_dax_range(dev_dax, dax_region->res.start, data->size);
if (rc)
goto err_range;