system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-11-05 18:23:50 +00:00
Code Issues Projects Releases Packages Wiki Activity

device-dax: ensure dev_dax->pgmap is valid for dynamic devices

Browse source 
Right now, only static dax regions have a valid @pgmap pointer in its
struct dev_dax.  Dynamic dax case however, do not.

In preparation for device-dax compound devmap support, make sure that
dev_dax pgmap field is set after it has been allocated and initialized.

dynamic dax device have the @pgmap is allocated at probe() and it's
managed by devm (contrast to static dax region which a pgmap is provided
and dax core kfrees it).  So in addition to ensure a valid @pgmap, clear
the pgmap when the dynamic dax device is released to avoid the same
pgmap ranges to be re-requested across multiple region device reconfigs.

Add a static_dev_dax() and use that helper in dev_dax_probe() to ensure
the initialization differences between dynamic and static regions are
more explicit.  While at it, consolidate the ranges initialization when
we allocate the @pgmap for the dynamic dax region case.  Also take the
opportunity to document the differences between static and dynamic da
regions.

Link: https://lkml.kernel.org/r/20211202204422.26777-8-joao.m.martins@oracle.com
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Joao Martins 2022-01-14 14:04:33 -08:00 committed by Linus Torvalds
parent 09b8013703
commit fc65c4eb0b
3 changed files with 54 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

32
drivers/dax/bus.c
View file

@ -129,11 +129,35 @@ ATTRIBUTE_GROUPS(dax_drv);
static int dax_bus_match(struct device *dev, struct device_driver *drv);
/*
* Static dax regions are regions created by an external subsystem
* nvdimm where a single range is assigned. Its boundaries are by the external
* subsystem and are usually limited to one physical memory range. For example,
* for PMEM it is usually defined by NVDIMM Namespace boundaries (i.e. a
* single contiguous range)
*
* On dynamic dax regions, the assigned region can be partitioned by dax core
* into multiple subdivisions. A subdivision is represented into one
* /dev/daxN.M device composed by one or more potentially discontiguous ranges.
*
* When allocating a dax region, drivers must set whether it's static
* (IORESOURCE_DAX_STATIC). On static dax devices, the @pgmap is pre-assigned
* to dax core when calling devm_create_dev_dax(), whereas in dynamic dax
* devices it is NULL but afterwards allocated by dax core on device ->probe().
* Care is needed to make sure that dynamic dax devices are torn down with a
* cleared @pgmap field (see kill_dev_dax()).
*/
static bool is_static(struct dax_region *dax_region)
{
return (dax_region->res.flags & IORESOURCE_DAX_STATIC) != 0;
}
bool static_dev_dax(struct dev_dax *dev_dax)
{
return is_static(dev_dax->region);
}
EXPORT_SYMBOL_GPL(static_dev_dax);
static u64 dev_dax_size(struct dev_dax *dev_dax)
{
u64 size = 0;
@ -363,6 +387,14 @@ void kill_dev_dax(struct dev_dax *dev_dax)
kill_dax(dax_dev);
unmap_mapping_range(inode->i_mapping, 0, 0, 1);
/*
* Dynamic dax region have the pgmap allocated via dev_kzalloc()
* and thus freed by devm. Clear the pgmap to not have stale pgmap
* ranges on probe() from previous reconfigurations of region devices.
*/
if (!static_dev_dax(dev_dax))
dev_dax->pgmap = NULL;
}
EXPORT_SYMBOL_GPL(kill_dev_dax);

1
drivers/dax/bus.h
View file

@ -48,6 +48,7 @@ int __dax_driver_register(struct dax_device_driver *dax_drv,
__dax_driver_register(driver, THIS_MODULE, KBUILD_MODNAME)
void dax_driver_unregister(struct dax_device_driver *dax_drv);
void kill_dev_dax(struct dev_dax *dev_dax);
bool static_dev_dax(struct dev_dax *dev_dax);
#if IS_ENABLED(CONFIG_DEV_DAX_PMEM_COMPAT)
int dev_dax_probe(struct dev_dax *dev_dax);

29
drivers/dax/device.c
View file

@ -398,18 +398,34 @@ int dev_dax_probe(struct dev_dax *dev_dax)
void *addr;
int rc, i;
pgmap = dev_dax->pgmap;
if (dev_WARN_ONCE(dev, pgmap && dev_dax->nr_range > 1,
"static pgmap / multi-range device conflict\n"))
return -EINVAL;
if (static_dev_dax(dev_dax)) {
if (dev_dax->nr_range > 1) {
dev_warn(dev,
"static pgmap / multi-range device conflict\n");
return -EINVAL;
}
pgmap = dev_dax->pgmap;
} else {
if (dev_dax->pgmap) {
dev_warn(dev,
"dynamic-dax with pre-populated page map\n");
return -EINVAL;
}
if (!pgmap) {
pgmap = devm_kzalloc(dev,
struct_size(pgmap, ranges, dev_dax->nr_range - 1),
GFP_KERNEL);
if (!pgmap)
return -ENOMEM;
pgmap->nr_range = dev_dax->nr_range;
dev_dax->pgmap = pgmap;
for (i = 0; i < dev_dax->nr_range; i++) {
struct range *range = &dev_dax->ranges[i].range;
pgmap->ranges[i] = *range;
}
}
for (i = 0; i < dev_dax->nr_range; i++) {
@ -421,9 +437,6 @@ int dev_dax_probe(struct dev_dax *dev_dax)
i, range->start, range->end);
return -EBUSY;
}
/* don't update the range for static pgmap */
if (!dev_dax->pgmap)
pgmap->ranges[i] = *range;
}
pgmap->type = MEMORY_DEVICE_GENERIC;