mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-11 12:28:41 +08:00
10b518d4e6
The ethtool netlink code uses common framework for passing arbitrary length bit sets to allow future extensions. A bitset can be a list (only one bitmap) or can consist of value and mask pair (used e.g. when client want to modify only some bits). A bitset can use one of two formats: verbose (bit by bit) or compact. Verbose format consists of bitset size (number of bits), list flag and an array of bit nests, telling which bits are part of the list or which bits are in the mask and which of them are to be set. In requests, bits can be identified by index (position) or by name. In replies, kernel provides both index and name. Verbose format is suitable for "one shot" applications like standard ethtool command as it avoids the need to either keep bit names (e.g. link modes) in sync with kernel or having to add an extra roundtrip for string set request (e.g. for private flags). Compact format uses one (list) or two (value/mask) arrays of 32-bit words to store the bitmap(s). It is more suitable for long running applications (ethtool in monitor mode or network management daemons) which can retrieve the names once and then pass only compact bitmaps to save space. Userspace requests can use either format; ETHTOOL_FLAG_COMPACT_BITSETS flag in request header tells kernel which format to use in reply. Notifications always use compact format. As some code uses arrays of unsigned long for internal representation and some arrays of u32 (or even a single u32), two sets of parse/compose helpers are introduced. To avoid code duplication, helpers for unsigned long arrays are implemented as wrappers around helpers for u32 arrays. There are two reasons for this choice: (1) u32 arrays are more frequent in ethtool code and (2) unsigned long array can be always interpreted as an u32 array on little endian 64-bit and all 32-bit architectures while we would need special handling for odd number of u32 words in the opposite direction. Signed-off-by: Michal Kubecek <mkubecek@suse.cz> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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.