linux-kernel - Re: [PATCH v3 2/3] docs-rst: driver-api: Add infiniband interface documentation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190201170902.GB13002@ziepe.ca>
Date:   Fri, 1 Feb 2019 10:09:02 -0700
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Joel Nider <joeln@...ibm.com>
Cc:     Jonathan Corbet <corbet@....net>,
        Leon Romanovsky <leon@...nel.org>,
        Doug Ledford <dledford@...hat.com>,
        Mike Rapoport <rppt@...ux.ibm.com>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] docs-rst: driver-api: Add infiniband interface
 documentation

On Tue, Jan 22, 2019 at 12:00:34PM +0200, Joel Nider wrote:
> A short document regarding the user verbs interface implementation on
> the kernel side. Also, the corresponding index entry in the
> documentation tree.
> 
> Signed-off-by: Joel Nider <joeln@...ibm.com>
>  Documentation/driver-api/index.rst      |  1 +
>  Documentation/driver-api/infiniband.rst | 73 +++++++++++++++++++++++++++++++++
>  2 files changed, 74 insertions(+)
>  create mode 100644 Documentation/driver-api/infiniband.rst
> 
> diff --git a/Documentation/driver-api/index.rst b/Documentation/driver-api/index.rst
> index ab38ced..ecb3f8a5 100644
> +++ b/Documentation/driver-api/index.rst
> @@ -28,6 +28,7 @@ available subsections can be seen below.
>     regulator
>     iio/index
>     input
> +   infiniband
>     usb/index
>     firewire
>     pci/index
> diff --git a/Documentation/driver-api/infiniband.rst b/Documentation/driver-api/infiniband.rst
> new file mode 100644
> index 0000000..2de47ff
> +++ b/Documentation/driver-api/infiniband.rst
> @@ -0,0 +1,73 @@
> +==========================
> +Infiniband Interface Guide
> +==========================
> +
> +This guide is for people who wish to understand the implementation details of
> +handler functions in the Infiniband subsystem. There are currently two system
> +calls for executing Infiniband commands: write() and ioctl(). Older commands
> +are sent to the kernel via write()s on the device files described in
> +:doc:`../userspace-api/rdma_user_verbs`. New commands must use the ioctl()
> +method. For completeness, both mechanisms are described here.
> +
> +The interface between userspace and kernel is kept in sync by checking the
> +version number. In the kernel, it is defined by IB_USER_VERBS_ABI_VERSION
> +(in include/uapi/rdma/ib_user_verbs.h).
> +
> +Write system call
> +-----------------
> +The entry point to the kernel is the ib_uverbs_write() function, which is
> +invoked as a response to the 'write' system call. The requested function is
> +looked up from an array called uverbs_cmd_table which contains function pointers
> +to the various command handlers.

This array was deleted recently

> +Write Command Handlers
> +~~~~~~~~~~~~~~~~~~~~~~
> +These command handler functions are declared
> +with the IB_VERBS_DECLARE_CMD macro in drivers/infiniband/core/uverbs.h. There
> +are also extended commands, which are kept in a similar manner in the
> +uverbs_ex_cmd_table. The extended commands use 64-bit values in the command
> +header, as opposed to the 32-bit values used in the regular command table.

IB_VERBS_DELCARE_CMD is also deleted

> +Objects trees are declared using the DECLARE_UVERBS_OBJECT_TREE macro. This
> +combines all of the objects.

DECLARE_UVERBS_OBJECT_TREE as well

Jason