by Oleksandr Natalenko

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Subject: Re: [RFC PATCH v3 00/13] module: core code clean up

Hello.

On p?tek 28. ledna 2022 21:39:21 CET Aaron Tomlin wrote:
> Hi Luis,
>
> [Note: Cc'd live-patching for feedback on livepatch specific changes]
>
> Firstly, apologies for the delay.
>
> As per your suggestion [1], this is an attempt to refactor and split
> optional code out of core module support code into separate components.
> This version is based on branch mcgrof/modules-next since a97ac8cb24a3/or
> modules-5.17-rc1. Please let me know your thoughts.
>
> Changes since v1 [2]:
>
> - Moved module version support code into a new file
>
> Changes since v2 [3]:
>
> - Move module decompress support to a separate file
> - Make check_modinfo_livepatch() generic (Petr Mladek)
> - Remove filename from each newly created file (Luis Chamberlain)
> - Addressed some (i.e. --ignore=ASSIGN_IN_IF,AVOID_BUG was used)
> minor scripts/checkpatch.pl concerns e.g., use strscpy over
> strlcpy and missing a blank line after declarations (Allen)

Thanks for your submission.

Aaron, could you please also include stats from `./scripts/bloat-o-meter` to compare `vmlinux` sections size before and after your modifications?

> [1]: https://lore.kernel.org/lkml/[email protected]/
> [2]: https://lore.kernel.org/lkml/[email protected]/
> [3]: https://lore.kernel.org/lkml/[email protected]/
>
>
> Aaron Tomlin (13):
> module: Move all into module/
> module: Simple refactor in preparation for split
> module: Move livepatch support to a separate file
> module: Move latched RB-tree support to a separate file
> module: Move arch strict rwx support to a separate file
> module: Move strict rwx support to a separate file
> module: Move extra signature support out of core code
> module: Move kmemleak support to a separate file
> module: Move kallsyms support into a separate file
> module: Move procfs support into a separate file
> module: Move sysfs support into a separate file
> module: Move kdb_modules list out of core code
> module: Move version support into a separate file
>
> MAINTAINERS | 2 +-
> include/linux/module.h | 92 +-
> kernel/Makefile | 5 +-
> kernel/debug/kdb/kdb_main.c | 5 +
> kernel/module-internal.h | 50 -
> kernel/module/Makefile | 18 +
> kernel/module/arch_strict_rwx.c | 44 +
> kernel/module/debug_kmemleak.c | 30 +
> .../decompress.c} | 2 +-
> kernel/module/internal.h | 202 ++
> kernel/module/kallsyms.c | 502 +++++
> kernel/module/livepatch.c | 74 +
> kernel/{module.c => module/main.c} | 1879 +----------------
> kernel/module/procfs.c | 142 ++
> .../signature.c} | 0
> kernel/module/signing.c | 120 ++
> kernel/module/strict_rwx.c | 83 +
> kernel/module/sysfs.c | 425 ++++
> kernel/module/tree_lookup.c | 108 +
> kernel/module/version.c | 110 +
> kernel/module_signing.c | 45 -
> 21 files changed, 2032 insertions(+), 1906 deletions(-)
> delete mode 100644 kernel/module-internal.h
> create mode 100644 kernel/module/Makefile
> create mode 100644 kernel/module/arch_strict_rwx.c
> create mode 100644 kernel/module/debug_kmemleak.c
> rename kernel/{module_decompress.c => module/decompress.c} (99%)
> create mode 100644 kernel/module/internal.h
> create mode 100644 kernel/module/kallsyms.c
> create mode 100644 kernel/module/livepatch.c
> rename kernel/{module.c => module/main.c} (63%)
> create mode 100644 kernel/module/procfs.c
> rename kernel/{module_signature.c => module/signature.c} (100%)
> create mode 100644 kernel/module/signing.c
> create mode 100644 kernel/module/strict_rwx.c
> create mode 100644 kernel/module/sysfs.c
> create mode 100644 kernel/module/tree_lookup.c
> create mode 100644 kernel/module/version.c
> delete mode 100644 kernel/module_signing.c
>
>
> base-commit: a97ac8cb24a3c3ad74794adb83717ef1605d1b47
>

--
Oleksandr Natalenko (post-factum)

2022-01-31 23:12:41

by Joe Perches

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Subject: Re: [RFC PATCH v3 03/13] module: Move livepatch support to a separate file

On Fri, 2022-01-28 at 20:39 +0000, Aaron Tomlin wrote:
> No functional change.
>
> This patch migrates livepatch support (i.e. used during module
> add/or load and remove/or deletion) from core module code into
> kernel/module/livepatch.c. At the moment it contains code to
> persist Elf information about a given livepatch module, only.
[]
> diff --git a/include/linux/module.h b/include/linux/module.h
[]
> @@ -668,11 +668,22 @@ static inline bool is_livepatch_module(struct module *mod)
> {
> return mod->klp;
> }
> +
> +static inline bool set_livepatch_module(struct module *mod)
> +{
> + mod->klp = true;
> + return true;
> +}
> #else /* !CONFIG_LIVEPATCH */
> static inline bool is_livepatch_module(struct module *mod)
> {
> return false;
> }
> +
> +static inline bool set_livepatch_module(struct module *mod)
> +{
> + return false;
> +}
> #endif /* CONFIG_LIVEPATCH */

style trivia:

Generally, these static inlines can be written deduplicating
the function declaration and using IS_ENABLED or #if inside
the definition.

Something like:

static inline bool is_livepatch_module(struct module *mod)
{
if (IS_ENABLED(CONFIG_LIVEPATCH)) {
mod->klp = true;
return true;
}
return false;
}

or

static inline bool is_livepatch_module(struct module *mod)
{
#ifdef CONFIG_LIVEPATCH
mod->klp = true;
return true;
#else
return false;
#endif
}