Messages in this thread Patch in this message | | | From | Xiaoming Ni <> | Subject | [PATCH v3] sysctl: Add a group of macro functions to initcall the sysctl table of each feature | Date | Mon, 13 Dec 2021 11:31:19 +0800 |
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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(). sysctl_init_bases() is executed before early_initcall(). do_sysctl_args() is executed after late_initcall(). To prevent the sysctl interface from being initialized before the feature itself. The lowest level of late_initcall() is safe as a normal sysctl interface registration level.
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> --- v3: Adjust the commit information description and add document comments to sysctl_initcall(). v2: https://lore.kernel.org/lkml/20211210085849.66169-1-nixiaoming@huawei.com/ Add a simple checkpatch check. Add code comment. v1: https://lore.kernel.org/lkml/20211207011320.100102-1-nixiaoming@huawei.com/ --- fs/coredump.c | 7 +------ fs/dcache.c | 7 +------ fs/exec.c | 8 +------- fs/file_table.c | 7 +------ fs/inode.c | 7 +------ fs/locks.c | 7 +------ fs/namei.c | 8 +------- fs/namespace.c | 7 +------ include/linux/sysctl.h | 34 ++++++++++++++++++++++++++++++++++ kernel/stackleak.c | 7 +------ scripts/checkpatch.pl | 6 ++++++ 11 files changed, 49 insertions(+), 56 deletions(-)
diff --git a/fs/coredump.c b/fs/coredump.c index 570d98398668..8f6c6322651d 100644 --- a/fs/coredump.c +++ b/fs/coredump.c @@ -943,12 +943,7 @@ static struct ctl_table coredump_sysctls[] = { { } }; -static int __init init_fs_coredump_sysctls(void) -{ - register_sysctl_init("kernel", coredump_sysctls); - return 0; -} -fs_initcall(init_fs_coredump_sysctls); +kernel_sysctl_initcall(coredump_sysctls); #endif /* CONFIG_SYSCTL */ /* diff --git a/fs/dcache.c b/fs/dcache.c index 0eef1102f460..c1570243aaee 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -195,12 +195,7 @@ static struct ctl_table fs_dcache_sysctls[] = { { } }; -static int __init init_fs_dcache_sysctls(void) -{ - register_sysctl_init("fs", fs_dcache_sysctls); - return 0; -} -fs_initcall(init_fs_dcache_sysctls); +fs_sysctl_initcall(fs_dcache_sysctls); #endif /* diff --git a/fs/exec.c b/fs/exec.c index cc5ec43df028..3c30e686af79 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -2124,11 +2124,5 @@ static struct ctl_table fs_exec_sysctls[] = { { } }; -static int __init init_fs_exec_sysctls(void) -{ - register_sysctl_init("fs", fs_exec_sysctls); - return 0; -} - -fs_initcall(init_fs_exec_sysctls); +fs_sysctl_initcall(fs_exec_sysctls); #endif /* CONFIG_SYSCTL */ diff --git a/fs/file_table.c b/fs/file_table.c index 57edef16dce4..52b60e9378a7 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -116,12 +116,7 @@ static struct ctl_table fs_stat_sysctls[] = { { } }; -static int __init init_fs_stat_sysctls(void) -{ - register_sysctl_init("fs", fs_stat_sysctls); - return 0; -} -fs_initcall(init_fs_stat_sysctls); +fs_sysctl_initcall(fs_stat_sysctls); #endif static struct file *__alloc_file(int flags, const struct cred *cred) diff --git a/fs/inode.c b/fs/inode.c index bef6ba9b8eb4..cd20d6dd8ffa 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -132,12 +132,7 @@ static struct ctl_table inodes_sysctls[] = { { } }; -static int __init init_fs_inode_sysctls(void) -{ - register_sysctl_init("fs", inodes_sysctls); - return 0; -} -early_initcall(init_fs_inode_sysctls); +fs_sysctl_initcall(inodes_sysctls); #endif static int no_open(struct inode *inode, struct file *file) diff --git a/fs/locks.c b/fs/locks.c index 8c6df10cd9ed..d86a74d19ed3 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -113,12 +113,7 @@ static struct ctl_table locks_sysctls[] = { {} }; -static int __init init_fs_locks_sysctls(void) -{ - register_sysctl_init("fs", locks_sysctls); - return 0; -} -early_initcall(init_fs_locks_sysctls); +fs_sysctl_initcall(locks_sysctls); #endif /* CONFIG_SYSCTL */ /* diff --git a/fs/namei.c b/fs/namei.c index 8d4f832f94aa..7eb636796fd4 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -1066,13 +1066,7 @@ static struct ctl_table namei_sysctls[] = { { } }; -static int __init init_fs_namei_sysctls(void) -{ - register_sysctl_init("fs", namei_sysctls); - return 0; -} -fs_initcall(init_fs_namei_sysctls); - +fs_sysctl_initcall(namei_sysctls); #endif /* CONFIG_SYSCTL */ /** diff --git a/fs/namespace.c b/fs/namespace.c index 647af66f313d..7117214b7a85 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -4626,11 +4626,6 @@ static struct ctl_table fs_namespace_sysctls[] = { { } }; -static int __init init_fs_namespace_sysctls(void) -{ - register_sysctl_init("fs", fs_namespace_sysctls); - return 0; -} -fs_initcall(init_fs_namespace_sysctls); +fs_sysctl_initcall(fs_namespace_sysctls); #endif /* CONFIG_SYSCTL */ diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index acf0805cf3a0..1c09894d453e 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -231,6 +231,40 @@ extern int sysctl_init_bases(void); extern void __register_sysctl_init(const char *path, struct ctl_table *table, const char *table_name); #define register_sysctl_init(path, table) __register_sysctl_init(path, table, #table) + +/** + * sysctl_initcall() - register and init sysctl leaf node to path + * @path: path name for sysctl base + * @table: sysctl leaf table to be registered to the path + * + * Leaf node in the sysctl tree: + * a) File, .child = NULL + * b) Directory, which is not shared by multiple features, .child != NULL + * + * The sysctl interface for each subfeature should be after sysctl_init_bases() + * and before do_sysctl_args(). + * sysctl_init_bases() is executed before early_initcall(). + * do_sysctl_args() is executed after late_initcall(). + * Therefore, it is safe to add leaves to the sysctl tree using late_initcall(). + */ +#define sysctl_initcall(path, table) \ + static int __init init_##table(void) \ + { \ + register_sysctl_init(path, table); \ + return 0;\ + } \ + late_initcall(init_##table) + +/* + * Use xxx_sysctl_initcall() to initialize your sysctl interface unless you want + * to register the sysctl directory and share it with other features. + */ +#define kernel_sysctl_initcall(table) sysctl_initcall("kernel", table) +#define fs_sysctl_initcall(table) sysctl_initcall("fs", table) +#define vm_sysctl_initcall(table) sysctl_initcall("vm", table) +#define debug_sysctl_initcall(table) sysctl_initcall("debug", table) +#define dev_sysctl_initcall(table) sysctl_initcall("dev", table) + extern struct ctl_table_header *register_sysctl_mount_point(const char *path); void do_sysctl_args(void); diff --git a/kernel/stackleak.c b/kernel/stackleak.c index 66b8af394e58..f084c1c787ba 100644 --- a/kernel/stackleak.c +++ b/kernel/stackleak.c @@ -57,12 +57,7 @@ static struct ctl_table stackleak_sysctls[] = { {} }; -static int __init stackleak_sysctls_init(void) -{ - register_sysctl_init("kernel", stackleak_sysctls); - return 0; -} -late_initcall(stackleak_sysctls_init); +kernel_sysctl_initcall(stackleak_sysctls); #endif /* CONFIG_SYSCTL */ #define skip_erasing() static_branch_unlikely(&stack_erasing_bypass) diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl index b01c36a15d9d..e8701d54b458 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) && -- 2.12.3
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