mainlining shenanigans
d9adf22a29
We can make all dumps and lookups lockless. Dumps currently only hold the nfnl mutex on the dump request itself. Dumps can span multiple syscalls, dump continuation doesn't acquire the nfnl mutex anywhere, i.e. the dump callbacks in nf_tables already use rcu and never rely on nfnl mutex being held. So, just switch all dumpers to rcu. This requires taking a module reference before dropping the rcu lock so rmmod is blocked, we also need to hold module reference over the entire dump operation sequence. netlink already supports this via the .module member in the netlink_dump_control struct. For the non-dump case (i.e. lookup of a specific tables, chains, etc), we need to swtich to _rcu list iteration primitive and make sure we use GFP_ATOMIC. This patch also adds the new nft_netlink_dump_start_rcu() helper that takes care of the get_ref, drop-rcu-lock,start dump, get-rcu-lock,put-ref sequence. The helper will be reused for all dumps. Rationale in all dump requests is: - use the nft_netlink_dump_start_rcu helper added in first patch - use GFP_ATOMIC and rcu list iteration - switch to .call_rcu ... thus making all dumps in nf_tables not depend on the nfnl mutex anymore. In the nf_tables_getgen: This callback just fetches the current base sequence, there is no need to serialize this with nfnl nft mutex. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| 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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.