modutils: merge module_entry and module_info to common

This merges the in-memory module info structures of modprobe
and depmod. This allows sharing hashing by modulename code
improving depmod runtime with almost factor of 2x.

function                                             old     new   delta
get_or_add_modentry                                    -      17     +17
do_modprobe                                          590     601     +11
moddb_get_or_create                                    -      10     +10
load_modules_dep                                     195     205     +10
moddb_get                                              -       7      +7
add_probe                                             81      78      -3
modprobe_main                                        721     714      -7
depmod_main                                          553     543     -10
config_file_action                                   434     421     -13
helper_get_module                                    160     144     -16
parse_module                                         343     320     -23
order_dep_list                                       105      82     -23
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 2/7 up/down: 55/-95)            Total: -40 bytes

Signed-off-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 113 insertions, 120 deletions

diff --git a/modutils/depmod.c b/modutils/depmod.c
index 9713aef92..e5f0e3d2b 100644
--- a/modutils/depmod.c
+++ b/modutils/depmod.c
@@ -21,21 +21,13 @@
  *   for each depends, look through our list of full paths and emit if found
  */
 
-typedef struct module_info {
-        struct module_info *next;
-        char *name, *modname;
-        llist_t *dependencies;
-        llist_t *aliases;
-        llist_t *symbols;
-        struct module_info *dnext, *dprev;
-} module_info;
-
 static int FAST_FUNC parse_module(const char *fname, struct stat *sb UNUSED_PARAM,
                                 void *data, int depth UNUSED_PARAM)
 {
-        module_info **first = (module_info **) data;
+        module_db *modules = data;
         char *image, *ptr;
-        module_info *info;
+        module_entry *e;
+
         /* Arbitrary. Was sb->st_size, but that breaks .gz etc */
         size_t len = (64*1024*1024 - 4096);
 
@@ -43,17 +35,10 @@ static int FAST_FUNC parse_module(const char *fname, struct stat *sb UNUSED_PARA
                 return TRUE;
 
         image = xmalloc_open_zipped_read_close(fname, &len);
-        info = xzalloc(sizeof(*info));
 
-        info->next = *first;
-        *first = info;
+        e = moddb_get_or_create(modules, bb_get_last_path_component_nostrip(fname));
+        e->name = xstrdup(fname + 2); /* skip "./" */
 
-        info->dnext = info->dprev = info;
-        info->name = xstrdup(fname + 2); /* skip "./" */
-        info->modname = filename2modname(
-                        bb_get_last_path_component_nostrip(fname),
-                        NULL
-        );
         for (ptr = image; ptr < image + len - 10; ptr++) {
                 if (is_prefixed_with(ptr, "depends=")) {
                         char *u;
@@ -62,11 +47,11 @@ static int FAST_FUNC parse_module(const char *fname, struct stat *sb UNUSED_PARA
                         for (u = ptr; *u; u++)
                                 if (*u == '-')
                                         *u = '_';
-                        ptr += string_to_llist(ptr, &info->dependencies, ",");
+                        ptr += string_to_llist(ptr, &e->deps, ",");
                 } else if (ENABLE_FEATURE_MODUTILS_ALIAS
                  && is_prefixed_with(ptr, "alias=")
                 ) {
-                        llist_add_to(&info->aliases, xstrdup(ptr + 6));
+                        llist_add_to(&e->aliases, xstrdup(ptr + 6));
                         ptr += strlen(ptr);
                 } else if (ENABLE_FEATURE_MODUTILS_SYMBOLS
                  && is_prefixed_with(ptr, "__ksymtab_")
@@ -77,7 +62,7 @@ static int FAST_FUNC parse_module(const char *fname, struct stat *sb UNUSED_PARA
                         ) {
                                 continue;
                         }
-                        llist_add_to(&info->symbols, xstrdup(ptr));
+                        llist_add_to(&e->symbols, xstrdup(ptr));
                         ptr += strlen(ptr);
                 }
         }
@@ -86,24 +71,13 @@ static int FAST_FUNC parse_module(const char *fname, struct stat *sb UNUSED_PARA
         return TRUE;
 }
 
-static module_info *find_module(module_info *modules, const char *modname)
-{
-        module_info *m;
-
-        for (m = modules; m != NULL; m = m->next)
-                if (strcmp(m->modname, modname) == 0)
-                        return m;
-        return NULL;
-}
-
-static void order_dep_list(module_info *modules, module_info *start,
-                        llist_t *add)
+static void order_dep_list(module_db *modules, module_entry *start, llist_t *add)
 {
-        module_info *m;
+        module_entry *m;
         llist_t *n;
 
         for (n = add; n != NULL; n = n->link) {
-                m = find_module(modules, n->data);
+                m = moddb_get(modules, n->data);
                 if (m == NULL)
                         continue;
 
@@ -118,7 +92,7 @@ static void order_dep_list(module_info *modules, module_info *start,
                 start->dprev = m;
 
                 /* recurse */
-                order_dep_list(modules, start, m->dependencies);
+                order_dep_list(modules, start, m->deps);
         }
 }
 
@@ -184,10 +158,12 @@ enum {
 int depmod_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int depmod_main(int argc UNUSED_PARAM, char **argv)
 {
-        module_info *modules, *m, *dep;
+        module_db modules;
+        module_entry *m, *dep;
         const char *moddir_base = "/";
         char *moddir, *version;
         struct utsname uts;
+        unsigned i;
         int tmp;
 
         getopt32(argv, "aAb:eF:nruqC:", &moddir_base, NULL, NULL);
@@ -211,7 +187,7 @@ int depmod_main(int argc UNUSED_PARAM, char **argv)
                 free(moddir);
 
         /* Scan modules */
-        modules = NULL;
+        memset(&modules, 0, sizeof(modules));
         if (*argv) {
                 do {
                         parse_module(*argv, /*sb (unused):*/ NULL, &modules, 0);
@@ -224,10 +200,11 @@ int depmod_main(int argc UNUSED_PARAM, char **argv)
         /* Generate dependency and alias files */
         if (!(option_mask32 & OPT_n))
                 xfreopen_write(CONFIG_DEFAULT_DEPMOD_FILE, stdout);
-        for (m = modules; m != NULL; m = m->next) {
+
+        moddb_foreach_module(&modules, m, i) {
                 printf("%s:", m->name);
 
-                order_dep_list(modules, m, m->dependencies);
+                order_dep_list(&modules, m, m->deps);
                 while (m->dnext != m) {
                         dep = m->dnext;
                         printf(" %s", dep->name);
@@ -243,10 +220,7 @@ int depmod_main(int argc UNUSED_PARAM, char **argv)
 #if ENABLE_FEATURE_MODUTILS_ALIAS
         if (!(option_mask32 & OPT_n))
                 xfreopen_write("modules.alias", stdout);
-        for (m = modules; m != NULL; m = m->next) {
-                char modname[MODULE_NAME_LEN];
-                const char *fname = bb_basename(m->name);
-                filename2modname(fname, modname);
+        moddb_foreach_module(&modules, m, i) {
                 while (m->aliases) {
                         /*
                          * Last word used to be a basename
@@ -256,34 +230,24 @@ int depmod_main(int argc UNUSED_PARAM, char **argv)
                          */
                         printf("alias %s %s\n",
                                 (char*)llist_pop(&m->aliases),
-                                modname);
+                                m->modname);
                 }
         }
 #endif
 #if ENABLE_FEATURE_MODUTILS_SYMBOLS
         if (!(option_mask32 & OPT_n))
                 xfreopen_write("modules.symbols", stdout);
-        for (m = modules; m != NULL; m = m->next) {
-                char modname[MODULE_NAME_LEN];
-                const char *fname = bb_basename(m->name);
-                filename2modname(fname, modname);
+        moddb_foreach_module(&modules, m, i) {
                 while (m->symbols) {
                         printf("alias symbol:%s %s\n",
                                 (char*)llist_pop(&m->symbols),
-                                modname);
+                                m->modname);
                 }
         }
 #endif
 
-        if (ENABLE_FEATURE_CLEAN_UP) {
-                while (modules) {
-                        module_info *old = modules;
-                        modules = modules->next;
-                        free(old->name);
-                        free(old->modname);
-                        free(old);
-                }
-        }
+        if (ENABLE_FEATURE_CLEAN_UP)
+                moddb_free(&modules);
 
         return EXIT_SUCCESS;
 }
diff --git a/modutils/modprobe.c b/modutils/modprobe.c
index 05bf02cf8..ec490b74d 100644
--- a/modutils/modprobe.c
+++ b/modutils/modprobe.c
@@ -150,19 +150,6 @@ static const char modprobe_longopts[] ALIGN1 =
 #define MODULE_FLAG_FOUND_IN_MODDEP     0x0004
 #define MODULE_FLAG_BLACKLISTED         0x0008
 
-struct module_entry { /* I'll call it ME. */
-        unsigned flags;
-        char *modname; /* stripped of /path/, .ext and s/-/_/g */
-        const char *probed_name; /* verbatim as seen on cmdline */
-        char *options; /* options from config files */
-        llist_t *realnames; /* strings. if this module is an alias, */
-        /* real module name is one of these. */
-//Can there really be more than one? Example from real kernel?
-        llist_t *deps; /* strings. modules we depend on */
-};
-
-#define DB_HASH_SIZE 256
-
 struct globals {
         llist_t *probes; /* MEs of module(s) requested on cmdline */
         char *cmdline_mopts; /* module options from cmdline */
@@ -170,7 +157,7 @@ struct globals {
         /* bool. "Did we have 'symbol:FOO' requested on cmdline?" */
         smallint need_symbols;
         struct utsname uts;
-        llist_t *db[DB_HASH_SIZE]; /* MEs of all modules ever seen (caching for speed) */
+        module_db db;
 } FIX_ALIASING;
 #define G (*ptr_to_globals)
 #define INIT_G() do { \
@@ -195,51 +182,9 @@ static char *gather_options_str(char *opts, const char *append)
         return opts;
 }
 
-/* These three functions called many times, optimizing for speed.
- * Users reported minute-long delays when they runn iptables repeatedly
- * (iptables use modprobe to install needed kernel modules).
- */
-static struct module_entry *helper_get_module(const char *module, int create)
-{
-        char modname[MODULE_NAME_LEN];
-        struct module_entry *e;
-        llist_t *l;
-        unsigned i;
-        unsigned hash;
-
-        filename2modname(module, modname);
-
-        hash = 0;
-        for (i = 0; modname[i]; i++)
-                hash = ((hash << 5) + hash) + modname[i];
-        hash %= DB_HASH_SIZE;
-
-        for (l = G.db[hash]; l; l = l->link) {
-                e = (struct module_entry *) l->data;
-                if (strcmp(e->modname, modname) == 0)
-                        return e;
-        }
-        if (!create)
-                return NULL;
-
-        e = xzalloc(sizeof(*e));
-        e->modname = xstrdup(modname);
-        llist_add_to(&G.db[hash], e);
-
-        return e;
-}
-static ALWAYS_INLINE struct module_entry *get_or_add_modentry(const char *module)
+static struct module_entry *get_or_add_modentry(const char *module)
 {
-        return helper_get_module(module, 1);
-}
-/* So far this function always gets a module pathname, never an alias name.
- * The crucial difference is that pathname needs dirname stripping,
- * while alias name must NOT do it!
- * Testcase where dirname stripping is likely to go wrong: "modprobe devname:snd/timer"
- */
-static ALWAYS_INLINE struct module_entry *get_modentry(const char *pathname)
-{
-        return helper_get_module(bb_get_last_path_component_nostrip(pathname), 0);
+        return moddb_get_or_create(&G.db, module);
 }
 
 static void add_probe(const char *name)
@@ -536,7 +481,7 @@ static void load_modules_dep(void)
                         continue;
                 *colon = '\0';
 
-                m = get_modentry(tokens[0]);
+                m = moddb_get(&G.db, bb_get_last_path_component_nostrip(tokens[0]));
                 if (m == NULL)
                         continue;
 
@@ -697,5 +642,8 @@ int modprobe_main(int argc UNUSED_PARAM, char **argv)
                 } while (me->realnames != NULL);
         }
 
+        if (ENABLE_FEATURE_CLEAN_UP)
+                moddb_free(&G.db);
+
         return (rc != 0);
 }
diff --git a/modutils/modutils.c b/modutils/modutils.c
index ef4134af5..8e9eef72d 100644
--- a/modutils/modutils.c
+++ b/modutils/modutils.c
@@ -16,6 +16,57 @@ extern int delete_module(const char *module, unsigned int flags);
 # define delete_module(mod, flags) syscall(__NR_delete_module, mod, flags)
 #endif
 
+static module_entry *helper_get_module(module_db *db, const char *module, int create)
+{
+        char modname[MODULE_NAME_LEN];
+        struct module_entry *e;
+        unsigned i, hash;
+
+        filename2modname(module, modname);
+
+        hash = 0;
+        for (i = 0; modname[i]; i++)
+                hash = ((hash << 5) + hash) + modname[i];
+        hash %= MODULE_HASH_SIZE;
+
+        for (e = db->buckets[hash]; e; e = e->next)
+                if (strcmp(e->modname, modname) == 0)
+                        return e;
+        if (!create)
+                return NULL;
+
+        e = xzalloc(sizeof(*e));
+        e->modname = xstrdup(modname);
+        e->next = db->buckets[hash];
+        db->buckets[hash] = e;
+        e->dnext = e->dprev = e;
+
+        return e;
+}
+module_entry* FAST_FUNC moddb_get(module_db *db, const char *module)
+{
+        return helper_get_module(db, module, 0);
+}
+module_entry* FAST_FUNC moddb_get_or_create(module_db *db, const char *module)
+{
+        return helper_get_module(db, module, 1);
+}
+
+void FAST_FUNC moddb_free(module_db *db)
+{
+        module_entry *e, *n;
+        unsigned i;
+
+        for (i = 0; i < MODULE_HASH_SIZE; i++) {
+                for (e = db->buckets[i]; e; e = n) {
+                        n = e->next;
+                        free(e->name);
+                        free(e->modname);
+                        free(e);
+                }
+        }
+}
+
 void FAST_FUNC replace(char *s, char what, char with)
 {
         while (*s) {
diff --git a/modutils/modutils.h b/modutils/modutils.h
index 5f059c716..2cbd1448a 100644
--- a/modutils/modutils.h
+++ b/modutils/modutils.h
@@ -16,6 +16,36 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
 /* linux/include/linux/module.h has 64, but this is also used
  * internally for the maximum alias name length, which can be quite long */
 #define MODULE_NAME_LEN 256
+#define MODULE_HASH_SIZE 256
+
+typedef struct module_entry {
+        struct module_entry *next;
+        char *name, *modname;
+        llist_t *deps;
+        IF_MODPROBE(
+                llist_t *realnames;
+                unsigned flags;
+                const char *probed_name; /* verbatim as seen on cmdline */
+                char *options; /* options from config files */
+        )
+        IF_DEPMOD(
+                llist_t *aliases;
+                llist_t *symbols;
+                struct module_entry *dnext, *dprev;
+        )
+} module_entry;
+
+typedef struct module_db {
+        module_entry *buckets[MODULE_HASH_SIZE];
+} module_db;
+
+#define moddb_foreach_module(db, module, index) \
+        for ((index) = 0; (index) < MODULE_HASH_SIZE; (index)++) \
+                for (module = (db)->buckets[index]; module; module = module->next)
+
+module_entry *moddb_get(module_db *db, const char *s) FAST_FUNC;
+module_entry *moddb_get_or_create(module_db *db, const char *s) FAST_FUNC;
+void moddb_free(module_db *db) FAST_FUNC;
 
 void replace(char *s, char what, char with) FAST_FUNC;
 char *replace_underscores(char *s) FAST_FUNC;