[PATCHv3 0/4] libnvme: add support for discovering multipath of a shared ns

[Nilay Shroff]

Hi Daniel, Hannes,

A gentle ping... Do you have any further comment for this patchset?

Thanks,
--Nilay

On 4/26/25 12:26 AM, Nilay Shroff wrote:
> Hi,
> 
> Recently released Linux kernel v6.15-rc1 added support for easily discovering
> multiple paths to a shared NVMe namespace. This multipath information is
> exposed to userspace via a new sysfs group attribute named "multipath",
> located under /sys/block/<ns-blkdev>/. More details on this functionality
> can be found here [1].
> 
> This patch series leverages that new functionality to discover multiple paths
> to a shared namespace and exposes that information in libnvme so that it can
> later be used by nvme-cli.
> 
> There are four patches in this series:
> The first patch adds support for discovering NVMe paths using the sysfs
> "multipath" group attribute.
> The second patch adds a new "queue_depth" attribute under the NVMe path
> object.
> The third patch adds a new "numa_nodes" attribute under the NVMe path object.
> The fourth patch extends the sysfs tree dump test to validate multipath link
> support
> 
> [1]: https://lore.kernel.org/all/20250112124154.60690-1-nilay@linux.ibm.com/
> 
> Changes from v2:
>     - Modified queue_depth get attribure function to always return the latest
>       value insteda of cached value (Hannes Reinecke)
> 
> Changes from v1:
>     - Fixed kernel version typo in the cover letter and commit
>     - Updated the commit in first patch to explain the change in some
>       detail (Daniel Wagner)
>     - Added fourth patch to validate changes (Daniel Wagner)
> 
> 
> Nilay Shroff (4):
>   tree: add support for discovering nvme paths using sysfs multipath
>     link
>   tree: add queue-depth attribute for nvme path object
>   tree: add attribute numa_nodes for NVMe path object
>   test: extend sysfs tree dump test
> 
>  src/libnvme.map                  |   2 +
>  src/nvme/filters.c               |   6 +
>  src/nvme/filters.h               |   9 ++
>  src/nvme/json.c                  |  90 +++++++++++++--
>  src/nvme/private.h               |  11 +-
>  src/nvme/tree.c                  | 191 ++++++++++++++++++++++---------
>  src/nvme/tree.h                  |  25 ++++
>  test/sysfs/data/tree-pcie.out    |  53 +++++++--
>  test/sysfs/data/tree-pcie.tar.xz | Bin 19712 -> 12656 bytes
>  9 files changed, 315 insertions(+), 72 deletions(-)
>