mirror of
https://github.com/hardkernel/linux.git
synced 2026-06-05 10:31:46 +09:00
d848eb0b32
[ Upstream commit 6b78debe1c07e6aa3c91ca0b1384bf3cb8217c50 ] Proper refcounts will always warn splat when something goes wrong, be it underflow, saturation or object resurrection. As these are always a source of bugs, use it in cls_u32 as a safeguard to prevent/catch issues. Another benefit is that the refcount API self documents the code, making clear when transitions to dead are expected. For such an update we had to make minor adaptations on u32 to fit the refcount API. First we set explicitly to '1' when objects are created, then the objects are alive until a 1 -> 0 happens, which is then released appropriately. The above made clear some redundant operations in the u32 code around the root_ht handling that were removed. The root_ht is created with a refcnt set to 1. Then when it's associated with tcf_proto it increments the refcnt to 2. Throughout the entire code the root_ht is an exceptional case and can never be referenced, therefore the refcnt never incremented/decremented. Its lifetime is always bound to tcf_proto, meaning if you delete tcf_proto the root_ht is deleted as well. The code made up for the fact that root_ht refcnt is 2 and did a double decrement to free it, which is not a fit for the refcount API. Even though refcount_t is implemented using atomics, we should observe a negligible control plane impact. Signed-off-by: Pedro Tammela <pctammela@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://lore.kernel.org/r/20231114141856.974326-2-pctammela@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Stable-dep-of: 73af53d82076 ("net: sched: cls_u32: Fix u32's systematic failure to free IDR entries for hnodes.") Signed-off-by: Sasha Levin <sashal@kernel.org>
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.