diff options
Diffstat (limited to 'fs/proc/proc_sysctl.c')
| -rw-r--r-- | fs/proc/proc_sysctl.c | 42 |
1 files changed, 31 insertions, 11 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 48f2d60bd78a..72f2b373221e 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -1281,7 +1281,10 @@ out: * __register_sysctl_table - register a leaf sysctl table * @set: Sysctl tree to register on * @path: The path to the directory the sysctl table is in. - * @table: the top-level table structure + * @table: the top-level table structure without any child. This table + * should not be free'd after registration. So it should not be + * used on stack. It can either be a global or dynamically allocated + * by the caller and free'd later after sysctl unregistration. * * Register a sysctl table hierarchy. @table should be a filled in ctl_table * array. A completely 0 filled entry terminates the table. @@ -1302,9 +1305,12 @@ out: * proc_handler - the text handler routine (described below) * * extra1, extra2 - extra pointers usable by the proc handler routines + * XXX: we should eventually modify these to use long min / max [0] + * [0] https://lkml.kernel.org/87zgpte9o4.fsf@email.froward.int.ebiederm.org * * Leaf nodes in the sysctl tree will be represented by a single file - * under /proc; non-leaf nodes will be represented by directories. + * under /proc; non-leaf nodes (where child is not NULL) are not allowed, + * sysctl_check_table() verifies this. * * There must be a proc_handler routine for any terminal nodes. * Several default handlers are available to cover common cases - @@ -1346,7 +1352,7 @@ struct ctl_table_header *__register_sysctl_table( spin_lock(&sysctl_lock); dir = &set->dir; - /* Reference moved down the diretory tree get_subdir */ + /* Reference moved down the directory tree get_subdir */ dir->header.nreg++; spin_unlock(&sysctl_lock); @@ -1363,6 +1369,11 @@ struct ctl_table_header *__register_sysctl_table( if (namelen == 0) continue; + /* + * namelen ensures if name is "foo/bar/yay" only foo is + * registered first. We traverse as if using mkdir -p and + * return a ctl_dir for the last directory entry. + */ dir = get_subdir(dir, name, namelen); if (IS_ERR(dir)) goto fail; @@ -1388,8 +1399,15 @@ fail: /** * register_sysctl - register a sysctl table - * @path: The path to the directory the sysctl table is in. - * @table: the table structure + * @path: The path to the directory the sysctl table is in. If the path + * doesn't exist we will create it for you. + * @table: the table structure. The calller must ensure the life of the @table + * will be kept during the lifetime use of the syctl. It must not be freed + * until unregister_sysctl_table() is called with the given returned table + * with this registration. If your code is non modular then you don't need + * to call unregister_sysctl_table() and can instead use something like + * register_sysctl_init() which does not care for the result of the syctl + * registration. * * Register a sysctl table. @table should be a filled in ctl_table * array. A completely 0 filled entry terminates the table. @@ -1405,8 +1423,11 @@ EXPORT_SYMBOL(register_sysctl); /** * __register_sysctl_init() - register sysctl table to path - * @path: path name for sysctl base - * @table: This is the sysctl table that needs to be registered to the path + * @path: path name for sysctl base. If that path doesn't exist we will create + * it for you. + * @table: This is the sysctl table that needs to be registered to the path. + * The caller must ensure the life of the @table will be kept during the + * lifetime use of the sysctl. * @table_name: The name of sysctl table, only used for log printing when * registration fails * @@ -1418,10 +1439,7 @@ EXPORT_SYMBOL(register_sysctl); * register_sysctl() failing on init are extremely low, and so for both reasons * this function does not return any error as it is used by initialization code. * - * Context: Can only be called after your respective sysctl base path has been - * registered. So for instance, most base directories are registered early on - * init before init levels are processed through proc_sys_init() and - * sysctl_init_bases(). + * Context: if your base directory does not exist it will be created for you. */ void __init __register_sysctl_init(const char *path, struct ctl_table *table, const char *table_name) @@ -1551,6 +1569,7 @@ out: * * Register a sysctl table hierarchy. @table should be a filled in ctl_table * array. A completely 0 filled entry terminates the table. + * We are slowly deprecating this call so avoid its use. * * See __register_sysctl_table for more details. */ @@ -1622,6 +1641,7 @@ err_register_leaves: * * Register a sysctl table hierarchy. @table should be a filled in ctl_table * array. A completely 0 filled entry terminates the table. + * We are slowly deprecating this caller so avoid future uses of it. * * See __register_sysctl_paths for more details. */ |