device-dax: introduce 'mapping' devices

In support of interrogating the physical address layout of a device with
dis-contiguous ranges, introduce a sysfs directory with 'start', 'end',
and 'page_offset' attributes.  The alternative is trying to parse
/proc/iomem, and that file will not reflect the extent layout until the
device is enabled.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joao Martins <joao.m.martins@oracle.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: Brice Goglin <Brice.Goglin@inria.fr>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: David Hildenbrand <david@redhat.com>
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: Ira Weiny <ira.weiny@intel.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: Jia He <justin.he@arm.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.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: Vishal Verma <vishal.l.verma@intel.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/159643104819.4062302.13691281391423291589.stgit@dwillia2-desk3.amr.corp.intel.com
Link: https://lkml.kernel.org/r/160106117446.30709.2751020815463722537.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/dax/dax-private.h b/drivers/dax/dax-private.h
index f863287107fd..13780f62b95e 100644
--- a/drivers/dax/dax-private.h
+++ b/drivers/dax/dax-private.h
@@ -40,6 +40,12 @@ struct dax_region {
 	struct device *youngest;
 };
 
+struct dax_mapping {
+	struct device dev;
+	int range_id;
+	int id;
+};
+
 /**
  * struct dev_dax - instance data for a subdivision of a dax region, and
  * data while the device is activated in the driver.
@@ -47,6 +53,7 @@ struct dax_region {
  * @dax_dev - core dax functionality
  * @target_node: effective numa node if dev_dax memory range is onlined
  * @id: ida allocated id
+ * @ida: mapping id allocator
  * @dev - device core
  * @pgmap - pgmap for memmap setup / lifetime (driver owned)
  * @nr_range: size of @ranges
@@ -57,12 +64,14 @@ struct dev_dax {
 	struct dax_device *dax_dev;
 	int target_node;
 	int id;
+	struct ida ida;
 	struct device dev;
 	struct dev_pagemap *pgmap;
 	int nr_range;
 	struct dev_dax_range {
 		unsigned long pgoff;
 		struct range range;
+		struct dax_mapping *mapping;
 	} *ranges;
 };
 
@@ -70,4 +79,9 @@ static inline struct dev_dax *to_dev_dax(struct device *dev)
 {
 	return container_of(dev, struct dev_dax, dev);
 }
+
+static inline struct dax_mapping *to_dax_mapping(struct device *dev)
+{
+	return container_of(dev, struct dax_mapping, dev);
+}
 #endif