Messages in this thread Patch in this message | | | Subject | Re: [PATCH] sysctl: Add a group of macro functions to initcall the sysctl table of each feature | From | Xiaoming Ni <> | Date | Tue, 7 Dec 2021 14:25:14 +0800 |
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On 2021/12/7 9:50, Joe Perches wrote: > On Mon, 2021-12-06 at 17:38 -0800, Andrew Morton wrote: >> On Tue, 7 Dec 2021 09:13:20 +0800 Xiaoming Ni <nixiaoming@huawei.com> wrote: >> >>> To avoid duplicated code, add a set of macro functions to initialize the >>> sysctl table for each feature. >>> >>> The system initialization process is as follows: >>> >>> start_kernel () { >>> ... >>> /* init proc and sysctl base, >>> * proc_root_init()-->proc_sys_init()-->sysctl_init_bases() >>> */ >>> proc_root_init(); /* init proc and sysctl base */ >>> ... >>> arch_call_rest_init(); >>> } >>> >>> arch_call_rest_init()-->rest_init()-->kernel_init() >>> kernel_init() { >>> ... >>> kernel_init_freeable(); /* do all initcalls */ >>> ... >>> do_sysctl_args(); /* Process the sysctl parameter: sysctl.*= */ >>> } >>> >>> kernel_init_freeable()--->do_basic_setup()-->do_initcalls() >>> do_initcalls() { >>> for (level = 0; level < ARRAY_SIZE(initcall_levels) - 1; level++) { >>> do_initcall_level >>> } >>> >>> The sysctl interface of each subfeature should be registered after >>> sysctl_init_bases() and before do_sysctl_args(). It seems that the sysctl >>> interface does not depend on initcall_levels. To prevent the sysctl >>> interface from being initialized before the feature itself. The >>> lowest-level late_initcall() is used as the common sysctl interface >>> registration level. >> >> I'm not normally a fan of wrapping commonly-used code sequences into >> magical macros, but this one does seem to make sense. >> >> I wonder if it is possible to cook up a checkpatch rule to tell people >> to henceforth use the magic macros rather than to open-code things in >> the old way. Sounds hard. > > Almost impossible for checkpatch. > Likely easier in coccinelle. >
Maybe we can add a rudimentary check to the checkpatch.
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b01c36a15d9d..26e953ae4cc5 100755 --- a/scripts/checkpatch.pl +++ b/scripts/checkpatch.pl @@ -7212,6 +7212,12 @@ sub process { "Deprecated use of '$deprecated_api', prefer '$new_api' instead\n" . $herecurr); }
+# check register_sysctl_init + if ($prevline =~ /{/ && $rawline =~ /\sregister_sysctl_init\(\"(kernel|fs|vm|debug|dev)\",\s+(.*)\)\;/) { + WARN("DEPRECATED_API", + "Deprecated use of 'register_sysctl_init(\"$1\", $2);', prefer '$1_sysctl_initcall($2);' instead\n".$herecurr); + } + # check for various structs that are normally const (ops, kgdb, device_tree) # and avoid what seem like struct definitions 'struct foo {' if (defined($const_structs) &&
Thanks Xiaoming Ni
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