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WSL2-Linux-Kernel
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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>
This commit is contained in:
Dan Williams 2020-10-13 16:50:24 -07:00 коммит произвёл Linus Torvalds
Родитель c77f520db8
Коммит fcffb6a1df
1 изменённых файлов: 152 добавлений и 9 удалений
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161
drivers/dax/bus.c
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@ -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;