From 1e887723545e037b5e200e77edf79802f58fc818 Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Wed, 9 Aug 2023 12:49:55 +0200 Subject: sysctl: Add ctl_table_size to ctl_table_header The new ctl_table_size element will hold the size of the ctl_table arrays contained in the ctl_table_header. This value should eventually be passed by the callers to the sysctl register infrastructure. And while this commit introduces the variable, it does not set nor use it because that requires case by case considerations for each caller. It provides two important things: (1) A place to put the result of the ctl_table array calculation when it gets introduced for each caller. And (2) the size that will be used as the additional stopping criteria in the list_for_each_table_entry macro (to be added when all the callers are migrated) Signed-off-by: Joel Granados Signed-off-by: Luis Chamberlain --- include/linux/sysctl.h | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 59d451f455bf..33252ad58ebe 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -159,12 +159,22 @@ struct ctl_node { struct ctl_table_header *header; }; -/* struct ctl_table_header is used to maintain dynamic lists of - struct ctl_table trees. */ +/** + * struct ctl_table_header - maintains dynamic lists of struct ctl_table trees + * @ctl_table: pointer to the first element in ctl_table array + * @ctl_table_size: number of elements pointed by @ctl_table + * @used: The entry will never be touched when equal to 0. + * @count: Upped every time something is added to @inodes and downed every time + * something is removed from inodes + * @nreg: When nreg drops to 0 the ctl_table_header will be unregistered. + * @rcu: Delays the freeing of the inode. Introduced with "unfuck proc_sysctl ->d_compare()" + * + */ struct ctl_table_header { union { struct { struct ctl_table *ctl_table; + int ctl_table_size; int used; int count; int nreg; -- cgit v1.2.3 From bff97cf11b261972cae90299432238cc9a9a6a51 Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Wed, 9 Aug 2023 12:49:57 +0200 Subject: sysctl: Add a size arg to __register_sysctl_table We make these changes in order to prepare __register_sysctl_table and its callers for when we remove the sentinel element (empty element at the end of ctl_table arrays). We don't actually remove any sentinels in this commit, but we *do* make sure to use ARRAY_SIZE so the table_size is available when the removal occurs. We add a table_size argument to __register_sysctl_table and adjust callers, all of which pass ctl_table pointers and need an explicit call to ARRAY_SIZE. We implement a size calculation in register_net_sysctl in order to forward the size of the array pointer received from the network register calls. The new table_size argument does not yet have any effect in the init_header call which is still dependent on the sentinel's presence. table_size *does* however drive the `kzalloc` allocation in __register_sysctl_table with no adverse effects as the allocated memory is either one element greater than the calculated ctl_table array (for the calls in ipc_sysctl.c, mq_sysctl.c and ucount.c) or the exact size of the calculated ctl_table array (for the call from sysctl_net.c and register_sysctl). This approach will allows us to "just" remove the sentinel without further changes to __register_sysctl_table as table_size will represent the exact size for all the callers at that point. Signed-off-by: Joel Granados Signed-off-by: Luis Chamberlain --- include/linux/sysctl.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 33252ad58ebe..0495c858989f 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -226,7 +226,7 @@ extern void retire_sysctl_set(struct ctl_table_set *set); struct ctl_table_header *__register_sysctl_table( struct ctl_table_set *set, - const char *path, struct ctl_table *table); + const char *path, struct ctl_table *table, size_t table_size); struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); void unregister_sysctl_table(struct ctl_table_header * table); -- cgit v1.2.3 From 9edbfe92a0a1355bae1e47c8f542ac0d39f19f8c Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Wed, 9 Aug 2023 12:49:58 +0200 Subject: sysctl: Add size to register_sysctl This commit adds table_size to register_sysctl in preparation for the removal of the sentinel elements in the ctl_table arrays (last empty markers). And though we do *not* remove any sentinels in this commit, we set things up by either passing the table_size explicitly or using ARRAY_SIZE on the ctl_table arrays. We replace the register_syctl function with a macro that will add the ARRAY_SIZE to the new register_sysctl_sz function. In this way the callers that are already using an array of ctl_table structs do not change. For the callers that pass a ctl_table array pointer, we pass the table_size to register_sysctl_sz instead of the macro. Signed-off-by: Joel Granados Suggested-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain --- include/linux/sysctl.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 0495c858989f..b1168ae281c9 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -215,6 +215,9 @@ struct ctl_path { const char *procname; }; +#define register_sysctl(path, table) \ + register_sysctl_sz(path, table, ARRAY_SIZE(table)) + #ifdef CONFIG_SYSCTL void proc_sys_poll_notify(struct ctl_table_poll *poll); @@ -227,7 +230,8 @@ extern void retire_sysctl_set(struct ctl_table_set *set); struct ctl_table_header *__register_sysctl_table( struct ctl_table_set *set, const char *path, struct ctl_table *table, size_t table_size); -struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table); +struct ctl_table_header *register_sysctl_sz(const char *path, struct ctl_table *table, + size_t table_size); void unregister_sysctl_table(struct ctl_table_header * table); extern int sysctl_init_bases(void); @@ -262,7 +266,9 @@ static inline struct ctl_table_header *register_sysctl_mount_point(const char *p return NULL; } -static inline struct ctl_table_header *register_sysctl(const char *path, struct ctl_table *table) +static inline struct ctl_table_header *register_sysctl_sz(const char *path, + struct ctl_table *table, + size_t table_size) { return NULL; } -- cgit v1.2.3 From 3bc269cfd3e119be84b69d95aec3a9e147016bb2 Mon Sep 17 00:00:00 2001 From: Joel Granados Date: Wed, 9 Aug 2023 12:49:59 +0200 Subject: sysctl: Add size arg to __register_sysctl_init This commit adds table_size to __register_sysctl_init in preparation for the removal of the sentinel elements in the ctl_table arrays (last empty markers). And though we do *not* remove any sentinels in this commit, we set things up by calculating the ctl_table array size with ARRAY_SIZE. We add a table_size argument to __register_sysctl_init and modify the register_sysctl_init macro to calculate the array size with ARRAY_SIZE. The original callers do not need to be updated as they will go through the new macro. Signed-off-by: Joel Granados Suggested-by: Greg Kroah-Hartman Signed-off-by: Luis Chamberlain --- include/linux/sysctl.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index b1168ae281c9..09d7429d67c0 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -236,8 +236,9 @@ void unregister_sysctl_table(struct ctl_table_header * table); 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) + const char *table_name, size_t table_size); +#define register_sysctl_init(path, table) \ + __register_sysctl_init(path, table, #table, ARRAY_SIZE(table)) extern struct ctl_table_header *register_sysctl_mount_point(const char *path); void do_sysctl_args(void); -- cgit v1.2.3