mirror of
https://github.com/torvalds/linux.git
synced 2026-08-02 13:22:02 +02:00
Linux kernel source tree
dbb0b6ca7d
From: Tony Nguyen <anthony.l.nguyen@intel.com> To: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, netdev@vger.kernel.org Cc: Tony Nguyen <anthony.l.nguyen@intel.com>, alan.brady@intel.com Tony Nguyen says: ==================== idpf: refactor virtchnl messages Alan Brady says: The motivation for this series has two primary goals. We want to enable support of multiple simultaneous messages and make the channel more robust. The way it works right now, the driver can only send and receive a single message at a time and if something goes really wrong, it can lead to data corruption and strange bugs. To start the series, we introduce an idpf_virtchnl.h file. This reduces the burden on idpf.h which is overloaded with struct and function declarations. The conversion works by conceptualizing a send and receive as a "virtchnl transaction" (idpf_vc_xn) and introducing a "transaction manager" (idpf_vc_xn_manager). The vcxn_mngr will init a ring of transactions from which the driver will pop from a bitmap of free transactions to track in-flight messages. Instead of needing to handle a complicated send/recv for every a message, the driver now just needs to fill out a xn_params struct and hand it over to idpf_vc_xn_exec which will take care of all the messy bits. Once a message is sent and receives a reply, we leverage the completion API to signal the received buffer is ready to be used (assuming success, or an error code otherwise). At a low-level, this implements the "sw cookie" field of the virtchnl message descriptor to enable this. We have 16 bits we can put whatever we want and the recipient is required to apply the same cookie to the reply for that message. We use the first 8 bits as an index into the array of transactions to enable fast lookups and we use the second 8 bits as a salt to make sure each cookie is unique for that message. As transactions are received in arbitrary order, it's possible to reuse a transaction index and the salt guards against index conflicts to make certain the lookup is correct. As a primitive example, say index 1 is used with salt 1. The message times out without receiving a reply so index 1 is renewed to be ready for a new transaction, we report the timeout, and send the message again. Since index 1 is free to be used again now, index 1 is again sent but now salt is 2. This time we do get a reply, however it could be that the reply is _actually_ for the previous send index 1 with salt 1. Without the salt we would have no way of knowing for sure if it's the correct reply, but with we will know for certain. Through this conversion we also get several other benefits. We can now more appropriately handle asynchronously sent messages by providing space for a callback to be defined. This notably allows us to handle MAC filter failures better; previously we could potentially have stale, failed filters in our list, which shouldn't really have a major impact but is obviously not correct. I also managed to remove fairly significant more lines than I added which is a win in my book. Additionally, this converts some variables to use auto-variables where appropriate. This makes the alloc paths much cleaner and less prone to memory leaks. We also fix a few virtchnl related bugs while we're here. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.