The patch titled
Subject: device-dax: add a range mapping allocation attribute
has been added to the -mm tree. Its filename is
device-dax-add-a-range-mapping-allocation-attribute.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/device-dax-add-a-range-mapping-allocation-attribute.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/device-dax-add-a-range-mapping-allocation-attribute.patch
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------------------------------------------------------
From: Joao Martins <joao.m.martins@xxxxxxxxxx>
Subject: device-dax: add a range mapping allocation attribute
Add a sysfs attribute which denotes a range from the dax region to be
allocated. It's an write only @mapping sysfs attribute in the format of
'<start>-<end>' to allocate a range. @start and @end use hexadecimal
values and the @pgoff is implicitly ordered wrt to previous writes to
@mapping sysfs e.g. a write of a range of length 1G the pgoff is
0..1G(-4K), a second write will use @pgoff for 1G+4K..<size>.
This range mapping interface is useful for:
1) Application which want to implement its own allocation logic, and
thus pick the desired ranges from dax_region.
2) For use cases like VMM fast restart[0] where after kexec we want
to the same gpa<->phys mappings (as originally created before kexec).
[0] https://static.sched.com/hosted_files/kvmforum2019/66/VMM-fast-restart_kvmforum2019.pdf
Link: https://lkml.kernel.org/r/159643106970.4062302.10402616567780784722.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20200716172913.19658-5-joao.m.martins@xxxxxxxxxx
Link: https://lkml.kernel.org/r/160106119570.30709.4548889722645210610.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Ben Skeggs <bskeggs@xxxxxxxxxx>
Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Brice Goglin <Brice.Goglin@xxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Hulk Robot <hulkci@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Jason Yan <yanaijie@xxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: "Jérôme Glisse" <jglisse@xxxxxxxxxx>
Cc: Jia He <justin.he@xxxxxxx>
Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: kernel test robot <lkp@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
Cc: Vivek Goyal <vgoyal@xxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/dax/bus.c | 64 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 64 insertions(+)
--- a/drivers/dax/bus.c~device-dax-add-a-range-mapping-allocation-attribute
+++ a/drivers/dax/bus.c
@@ -1043,6 +1043,67 @@ static ssize_t size_store(struct device
}
static DEVICE_ATTR_RW(size);
+static ssize_t range_parse(const char *opt, size_t len, struct range *range)
+{
+ unsigned long long addr = 0;
+ char *start, *end, *str;
+ ssize_t rc = EINVAL;
+
+ str = kstrdup(opt, GFP_KERNEL);
+ if (!str)
+ return rc;
+
+ end = str;
+ start = strsep(&end, "-");
+ if (!start || !end)
+ goto err;
+
+ rc = kstrtoull(start, 16, &addr);
+ if (rc)
+ goto err;
+ range->start = addr;
+
+ rc = kstrtoull(end, 16, &addr);
+ if (rc)
+ goto err;
+ range->end = addr;
+
+err:
+ kfree(str);
+ return rc;
+}
+
+static ssize_t mapping_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct dev_dax *dev_dax = to_dev_dax(dev);
+ struct dax_region *dax_region = dev_dax->region;
+ size_t to_alloc;
+ struct range r;
+ ssize_t rc;
+
+ rc = range_parse(buf, len, &r);
+ if (rc)
+ return rc;
+
+ rc = -ENXIO;
+ device_lock(dax_region->dev);
+ if (!dax_region->dev->driver) {
+ device_unlock(dax_region->dev);
+ return rc;
+ }
+ device_lock(dev);
+
+ to_alloc = range_len(&r);
+ if (alloc_is_aligned(dev_dax, to_alloc))
+ rc = alloc_dev_dax_range(dev_dax, r.start, to_alloc);
+ device_unlock(dev);
+ device_unlock(dax_region->dev);
+
+ return rc == 0 ? len : rc;
+}
+static DEVICE_ATTR_WO(mapping);
+
static ssize_t align_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1175,6 +1236,8 @@ static umode_t dev_dax_visible(struct ko
return 0;
if (a == &dev_attr_numa_node.attr && !IS_ENABLED(CONFIG_NUMA))
return 0;
+ if (a == &dev_attr_mapping.attr && is_static(dax_region))
+ return 0;
if ((a == &dev_attr_align.attr ||
a == &dev_attr_size.attr) && is_static(dax_region))
return 0444;
@@ -1184,6 +1247,7 @@ static umode_t dev_dax_visible(struct ko
static struct attribute *dev_dax_attributes[] = {
&dev_attr_modalias.attr,
&dev_attr_size.attr,
+ &dev_attr_mapping.attr,
&dev_attr_target_node.attr,
&dev_attr_align.attr,
&dev_attr_resource.attr,
_
Patches currently in -mm which might be from joao.m.martins@xxxxxxxxxx are
acpi-hmat-refactor-hmat_register_target_device-to-hmem_register_device-fix.patch
acpi-hmat-attach-a-device-for-each-soft-reserved-range-fix.patch
device-dax-make-align-a-per-device-property.patch
dax-hmem-introduce-dax_hmemregion_idle-parameter.patch
device-dax-add-a-range-mapping-allocation-attribute.patch
