From: Jessica Yu <jeyu@kernel.org>
To: Matthias Maennich <maennich@google.com>
Cc: linux-kernel@vger.kernel.org, kernel-team@android.com,
arnd@arndb.de, gregkh@linuxfoundation.org,
joel@joelfernandes.org, lucas.de.marchi@gmail.com,
maco@android.com, sspatil@google.com, will@kernel.org,
yamada.masahiro@socionext.com, linux-kbuild@vger.kernel.org,
linux-modules@vger.kernel.org, linux-usb@vger.kernel.org,
usb-storage@lists.one-eyed-alien.net
Subject: Re: [PATCH v5 00/11] Symbol Namespaces
Date: Mon, 9 Sep 2019 10:35:23 +0200 [thread overview]
Message-ID: <20190909083522.GA446@linux-8ccs> (raw)
In-Reply-To: <20190906103235.197072-1-maennich@google.com>
+++ Matthias Maennich [06/09/19 11:32 +0100]:
>As of Linux 5.3-rc7, there are 31207 [1] exported symbols in the kernel.
>That is a growth of roughly 1000 symbols since 4.17 (30206 [2]). There
>seems to be some consensus amongst kernel devs that the export surface
>is too large, and hard to reason about.
>
>Generally, these symbols fall in one of these categories:
>1) Symbols actually meant for drivers
>2) Symbols that are only exported because functionality is split over
> multiple modules, yet they really shouldn't be used by modules outside
> of their own subsystem
>3) Symbols really only meant for in-tree use
>
>When module developers try to upstream their code, it regularly turns
>out that they are using exported symbols that they really shouldn't be
>using. This problem is even bigger for drivers that are currently
>out-of-tree, which may be using many symbols that they shouldn't be
>using, and that break when those symbols are removed or modified.
>
>This patch allows subsystem maintainers to partition their exported
>symbols into separate namespaces, and module authors to import such
>namespaces only when needed.
>
>This allows subsystem maintainers to more easily limit availability of
>these namespaced symbols to other parts of the kernel. It can also be
>used to partition the set of exported symbols for documentation
>purposes; for example, a set of symbols that is really only used for
>debugging could be in a "SUBSYSTEM_DEBUG" namespace.
>
>I continued the work mainly done by Martijn Coenen.
>
>Changes in v2:
>- Rather than adding and evaluating separate sections __knsimport_NS,
> use modinfo tags to declare the namespaces a module introduces.
> Adjust modpost and the module loader accordingly.
>- Also add support for reading multiple modinfo values for the same tag
> to allow list-like access to modinfo tags.
>- The macros in export.h have been cleaned up to avoid redundancy in the
> macro parameters (ns, nspost, nspost2).
>- The introduction of relative references in the ksymtab entries caused
> a rework of the macros to accommodate that configuration as well.
>- Alignment of kernel_symbol in the ksymtab needed to be fixed to allow
> growing the kernel_symbol struct.
>- Modpost does now also append the namespace suffix to the symbol
> entries in Module.symvers.
>- The configuration option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS allows
> relaxing the enforcement of properly declared namespace imports at
> module loading time.
>- Symbols can be collectively exported into a namespace by defining
> DEFAULT_SYMBOL_NAMESPACE in the corresponding Makefile.
>- The requirement for a very recent coccinelle spatch has been lifted by
> simplifying the script.
>- nsdeps does now ensures MODULE_IMPORT_NS statements are sorted when
> patching the module source files.
>- Some minor bugs have been addressed in nsdeps to allow it to work with
> modules that have more than one source file.
>- The RFC for the usb-storage symbols has been simplified by using
> DEFAULT_SYMBOL_NAMESPACE=USB_STORAGE rather than explicitly exporting
> each and every symbol into that new namespace.
>
>Changes in v3:
>- Reword the documentation for the
> MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS option for clarification.
>- Fix printed required version of spatch in coccinelle script.
>- Adopt kbuild changes for modpost: .mod files are no longer generated
> in .tmp_versions. Similarely, generate the .ns_deps files in the tree
> along with the .mod files. Also, nsdeps now uses modules.order as
> source for the list modules to consider.
>- Add an RFC patch to introduce the namespace WATCHDOG_CORE for symbols
> exported in watchdog_core.c.
>
>Changes in v4:
>- scripts/nsdeps:
> - exit on first error
> - support out-of-tree builds O=...
>- scripts/export_report.pl: update for new Module.symvers format
>- scripts/mod/modpost: make the namespace a separate field when
> exporting to Module.symvers (rather than symbol.NS)
>- include/linux/export.h: fixed style nits
>- kernel/module.c: ensure namespaces are imported before taking a
> reference to the owner module
>- Documentation: document the Symbol Namespace feature and update
> references to Module.symvers and EXPORT_SYMBOL*
>
>Changes in v5:
>- Makefile: let 'nsdeps' depend on 'modules' to allow
> `make clean; make nsdeps` to work
>- scripts/nsdeps: drop 'exit on first error' again as it just makes more
> problems than it solves
>- drop the watchdog RFC patch for now
>
>This patch series was developed against v5.3-rc7.
Great work Matthias!
I think this patchset is shaping up nicely. As the merge window is
coming up soon, I'd like to queue this up in modules-next by the end
of today to allow for some testing and "soak" time in linux-next. If
there are any more complaints, please speak up.
Thanks!
Jessica
prev parent reply other threads:[~2019-09-09 8:35 UTC|newest]
Thread overview: 107+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180716122125.175792-1-maco@android.com>
[not found] ` <20180716122125.175792-3-maco@android.com>
[not found] ` <CAB0TPYEOVHcFGFLTjVvk7R0VSgSnXZRi1PjSYXONJSjqd4NewQ@mail.gmail.com>
[not found] ` <20180725155507.umb5oatduquxwlmt@linux-8ccs>
2018-07-25 16:48 ` [PATCH 2/6] module: add support for symbol namespaces Lucas De Marchi
2018-07-26 7:44 ` Martijn Coenen
2019-08-13 12:16 ` [PATCH v2 0/10] Symbol namespaces - RFC Matthias Maennich
2019-08-13 12:16 ` [PATCH v2 01/10] module: support reading multiple values per modinfo tag Matthias Maennich
2019-08-13 12:40 ` Greg KH
2019-08-13 12:16 ` [PATCH v2 02/10] export: explicitly align struct kernel_symbol Matthias Maennich
2019-08-13 12:41 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 03/10] module: add support for symbol namespaces Matthias Maennich
2019-08-13 15:26 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 04/10] modpost: " Matthias Maennich
2019-08-13 15:27 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 05/10] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-08-13 18:17 ` Greg KH
2019-08-13 20:15 ` Saravana Kannan
2019-08-14 12:54 ` Matthias Maennich
2019-08-14 17:34 ` Saravana Kannan
2019-08-13 12:17 ` [PATCH v2 06/10] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-08-13 18:16 ` Greg KH
2019-08-13 18:16 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 07/10] modpost: add support for generating namespace dependencies Matthias Maennich
2019-08-13 18:21 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 08/10] scripts: Coccinelle script for " Matthias Maennich
2019-08-13 12:31 ` Julia Lawall
2019-08-13 12:44 ` Greg KH
2019-08-14 6:36 ` [Cocci] " Himanshu Jha
2019-08-14 8:03 ` Matthias Maennich
2019-08-14 12:00 ` [v2 " Markus Elfring
2019-08-15 13:50 ` Markus Elfring
2019-08-22 9:18 ` Matthias Maennich
2019-08-22 11:00 ` Markus Elfring
2019-08-13 12:17 ` [PATCH v2 09/10] usb-storage: remove single-use define for debugging Matthias Maennich
2019-08-13 12:42 ` Greg KH
2019-08-13 13:12 ` Greg KH
2019-08-13 12:17 ` [PATCH v2 10/10] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-08-13 12:45 ` Greg KH
2019-08-13 12:47 ` Greg KH
2019-08-13 15:02 ` Matthias Maennich
[not found] ` <20190821114955.12788-1-maennich@google.com>
2019-08-21 11:49 ` [PATCH v3 01/11] module: support reading multiple values per modinfo tag Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 02/11] export: explicitly align struct kernel_symbol Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 03/11] module: add support for symbol namespaces Matthias Maennich
2019-08-27 15:37 ` Jessica Yu
2019-08-27 16:04 ` Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 04/11] modpost: " Matthias Maennich
2019-08-26 16:21 ` Jessica Yu
2019-08-27 14:41 ` Matthias Maennich
2019-08-28 9:43 ` Jessica Yu
2019-08-28 9:55 ` Matthias Maennich
2019-08-28 10:16 ` Jessica Yu
2019-08-21 11:49 ` [PATCH v3 05/11] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 06/11] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-08-28 10:49 ` Jessica Yu
2019-08-28 10:56 ` Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 07/11] modpost: add support for generating namespace dependencies Matthias Maennich
2019-08-21 11:49 ` [PATCH v3 08/11] scripts: Coccinelle script for " Matthias Maennich
2019-08-22 6:09 ` [v3 " Markus Elfring
2019-08-29 12:13 ` [PATCH v3 " Jessica Yu
2019-08-21 11:49 ` [PATCH v3 09/11] usb-storage: remove single-use define for debugging Matthias Maennich
2019-08-21 12:37 ` Greg KH
2019-08-21 13:21 ` Thomas Gleixner
2019-08-21 13:32 ` Greg KH
2019-08-21 11:49 ` [PATCH v3 10/11] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-08-21 12:38 ` Greg KH
2019-08-21 14:36 ` Jessica Yu
2019-08-21 23:13 ` Christoph Hellwig
2019-08-22 8:32 ` Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 00/12] Symbol Namespaces Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 01/12] module: support reading multiple values per modinfo tag Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 02/12] export: explicitly align struct kernel_symbol Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 03/12] module: add support for symbol namespaces Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 04/12] modpost: " Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 05/12] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 06/12] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 07/12] modpost: add support for generating namespace dependencies Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 08/12] scripts: Coccinelle script for " Matthias Maennich
2019-09-04 9:53 ` Masahiro Yamada
2019-09-05 14:46 ` Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 09/12] docs: Add documentation for Symbol Namespaces Matthias Maennich
2019-09-04 7:16 ` Greg KH
2019-09-03 15:06 ` [PATCH v4 10/12] usb-storage: remove single-use define for debugging Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 11/12] RFC: usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-09-03 15:06 ` [PATCH v4 12/12] RFC: watchdog: export core symbols in WATCHDOG_CORE namespace Matthias Maennich
2019-09-03 16:10 ` Guenter Roeck
2019-09-04 8:45 ` Masahiro Yamada
2019-09-04 12:12 ` Guenter Roeck
2019-09-04 16:16 ` [usb-storage] " Matthew Dharm
2019-09-05 10:41 ` Jessica Yu
2019-09-05 10:52 ` Arnd Bergmann
2019-09-05 11:16 ` Jessica Yu
2019-09-05 11:25 ` Masahiro Yamada
2019-09-05 12:00 ` Greg Kroah-Hartman
2019-09-05 11:25 ` Matthias Maennich
2019-09-04 9:37 ` [PATCH v4 00/12] Symbol Namespaces Masahiro Yamada
2019-09-06 10:32 ` [PATCH v5 00/11] " Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 01/11] module: support reading multiple values per modinfo tag Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 02/11] export: explicitly align struct kernel_symbol Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 03/11] module: add support for symbol namespaces Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 04/11] modpost: " Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 05/11] module: add config option MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 06/11] export: allow definition default namespaces in Makefiles or sources Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 07/11] modpost: add support for generating namespace dependencies Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 08/11] scripts: Coccinelle script for " Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 09/11] docs: Add documentation for Symbol Namespaces Matthias Maennich
2019-09-06 10:32 ` [PATCH v5 10/11] usb-storage: remove single-use define for debugging Matthias Maennich
2019-09-06 12:59 ` Jessica Yu
2019-09-06 13:22 ` Greg KH
2019-09-06 10:32 ` [PATCH v5 11/11] usb-storage: export symbols in USB_STORAGE namespace Matthias Maennich
2019-09-09 8:35 ` Jessica Yu [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190909083522.GA446@linux-8ccs \
--to=jeyu@kernel.org \
--cc=arnd@arndb.de \
--cc=gregkh@linuxfoundation.org \
--cc=joel@joelfernandes.org \
--cc=kernel-team@android.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-modules@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=lucas.de.marchi@gmail.com \
--cc=maco@android.com \
--cc=maennich@google.com \
--cc=sspatil@google.com \
--cc=usb-storage@lists.one-eyed-alien.net \
--cc=will@kernel.org \
--cc=yamada.masahiro@socionext.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).