From: Joao Martins <joao.m.martins@oracle.com>
To: linux-mm@kvack.org
Cc: Dan Williams <dan.j.williams@intel.com>,
Vishal Verma <vishal.l.verma@intel.com>,
Dave Jiang <dave.jiang@intel.com>,
Naoya Horiguchi <naoya.horiguchi@nec.com>,
Matthew Wilcox <willy@infradead.org>,
Jason Gunthorpe <jgg@ziepe.ca>,
John Hubbard <jhubbard@nvidia.com>,
Jane Chu <jane.chu@oracle.com>,
Muchun Song <songmuchun@bytedance.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Jonathan Corbet <corbet@lwn.net>, Christoph Hellwig <hch@lst.de>,
nvdimm@lists.linux.dev, linux-doc@vger.kernel.org,
Joao Martins <joao.m.martins@oracle.com>
Subject: [PATCH v6 07/10] device-dax: ensure dev_dax->pgmap is valid for dynamic devices
Date: Wed, 24 Nov 2021 19:10:02 +0000 [thread overview]
Message-ID: <20211124191005.20783-8-joao.m.martins@oracle.com> (raw)
In-Reply-To: <20211124191005.20783-1-joao.m.martins@oracle.com>
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.
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
---
drivers/dax/bus.c | 32 ++++++++++++++++++++++++++++++++
drivers/dax/bus.h | 1 +
drivers/dax/device.c | 29 +++++++++++++++++++++--------
3 files changed, 54 insertions(+), 8 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index 6cc4da4c713d..a22350e822fa 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -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);
diff --git a/drivers/dax/bus.h b/drivers/dax/bus.h
index 1e946ad7780a..4acdfee7dd59 100644
--- a/drivers/dax/bus.h
+++ b/drivers/dax/bus.h
@@ -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);
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 038816b91af6..630de5a795b0 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -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;
--
2.17.2
next prev parent reply other threads:[~2021-11-24 19:10 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-24 19:09 [PATCH v6 00/10] mm, device-dax: Introduce compound pages in devmap Joao Martins
2021-11-24 19:09 ` [PATCH v6 01/10] memory-failure: fetch compound_head after pgmap_pfn_valid() Joao Martins
2021-11-24 19:09 ` [PATCH v6 02/10] mm/page_alloc: split prep_compound_page into head and tail subparts Joao Martins
2021-11-24 19:09 ` [PATCH v6 03/10] mm/page_alloc: refactor memmap_init_zone_device() page init Joao Martins
2021-11-24 19:09 ` [PATCH v6 04/10] mm/memremap: add ZONE_DEVICE support for compound pages Joao Martins
2021-11-25 6:11 ` Christoph Hellwig
2021-11-25 11:35 ` Joao Martins
2021-11-24 19:10 ` [PATCH v6 05/10] device-dax: use ALIGN() for determining pgoff Joao Martins
2021-11-24 19:10 ` [PATCH v6 06/10] device-dax: use struct_size() Joao Martins
2021-11-24 19:10 ` Joao Martins [this message]
2021-11-24 19:10 ` [PATCH v6 08/10] device-dax: factor out page mapping initialization Joao Martins
2021-11-24 19:10 ` [PATCH v6 09/10] device-dax: set mapping prior to vmf_insert_pfn{,_pmd,pud}() Joao Martins
2021-11-25 11:42 ` Joao Martins
2021-11-26 18:39 ` Joao Martins
2021-11-29 7:32 ` Christoph Hellwig
2021-11-29 15:49 ` Joao Martins
2021-11-29 16:48 ` Christoph Hellwig
2021-11-29 17:20 ` Joao Martins
2021-11-24 19:10 ` [PATCH v6 10/10] device-dax: compound devmap support Joao Martins
2021-11-24 22:30 ` [PATCH v6 00/10] mm, device-dax: Introduce compound pages in devmap Dan Williams
2021-11-24 22:41 ` Andrew Morton
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