[ndctl PATCH 0/4] libdaxctl: Fix multi-range memory block handling

[Alison Schofield <alison.schofield@intel.com>]

[ Gregory: Hoping you can help w reviews here ]

Review and testing of Gregory's dax kmem atomic whole-device hotplug
series[1] exposed an existing libdaxctl bug when handling DAX devices with
multiple physical address ranges.

libdaxctl identifies a device's memory blocks using a single contiguous
address window, even when the device has separate ranges with gaps between
them. This can exclude blocks belonging to the device and include blocks
belonging to another device in the gaps. As a result, daxctl can report
incorrect memory block counts and potentially online or offline another
device's memory.

Patches 1-2 address mapping reliability issues discovered while fixing
the memory block ownership checks.

Patch 3 corrects the memory block ownership checks.

Patch 4 adds regression coverage using a two-range DAX device.

[1] https://lore.kernel.org/linux-cxl/20261016214248.443247-1-gourry@gourry.net/

Alison Schofield (4):
  libdaxctl: handle mapping initialization failures
  libdaxctl: tie mapping cache lifetime to the device
  libdaxctl: match memory blocks against each dax device mapping
  test/daxctl-create.sh: count memory blocks across dax mappings

 daxctl/lib/libdaxctl.c | 93 ++++++++++++++++++++++++++++++++++--------
 test/daxctl-create.sh  | 58 ++++++++++++++++++++++++++
 2 files changed, 135 insertions(+), 16 deletions(-)

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2.37.3