kmodloader: fix and optimize loading of failed modules

1) Restore functionality which was lost in commit 876c7f5b.
   Again at boot time kmodloader can load all modules (/etc/modules.d/*)
   even if dependency information is completely missing.
   This functionality is important in case of hidden dependency (not symbol dependency).
   For example, in kernel 4.4.60 is hidden dependency between nf_nat_ipv6 and nf_conntrack_ipv6.
   We can't load nf_nat_ipv6 before nf_conntrack_ipv6 and modinfo do not show this dependency.
   Two sequential load attempts of nf_nat_ipv6 may not be enough (in my case it's definitely not enough).
   nf_nat_ipv4 has a similar problem.

2) Reduce count of attempts to load failed modules.
   Now kmodloader try to load failed modules after all others are loaded.

main_loader: Count of failed and successful attempts to load nf_nat_ipv6.ko (kernel 4.4.60) depend on ubox version:
   COMMIT        FAILED      SUCCESSFUL     TOTAL
   128bc35f      53          1              54
   876c7f5b      2           0              2
   this          1           1              2

Signed-off-by: Pavel Merzlyakov <pavel.merzlyakov@gmail.com>
Acked-by: Jo-Philipp Wich <jo@mein.io>

diff --git a/kmodloader.c b/kmodloader.c
index 2e920ef40ca6c6e966ece78784ecd35c4420e68d..6a7d7c1f52bc8ad9b4f4da052974d6dd56616083 100644 (file)
--- a/kmodloader.c
+++ b/kmodloader.c
@@ -617,12 +617,13 @@ static void load_moddeps(struct module *_m)
        }
 }
 
-static int iterations = 0;
-static int load_modprobe(void)
+static int load_modprobe(bool allow_load_retry)
 {
-       int loaded, todo;
+       int loaded, skipped, failed;
        struct module_node *mn;
        struct module *m;
+       bool load_retry = false;
+       static bool first_iteration = true;
 
        avl_for_each_element(&modules, mn, avl) {
                if (mn->is_alias)
@@ -634,12 +635,13 @@ static int load_modprobe(void)
 
        do {
                loaded = 0;
-               todo = 0;
+               skipped = 0;
+               failed = 0;
                avl_for_each_element(&modules, mn, avl) {
                        if (mn->is_alias)
                                continue;
                        m = mn->m;
-                       if ((m->state == PROBE) && (!deps_available(m, 0)) && m->error < 2) {
+                       if ((m->state == PROBE) && (!deps_available(m, 0)) && (!m->error || load_retry)) {
                                if (!insert_module(get_module_path(m->name), (m->opts) ? (m->opts) : (""))) {
                                        m->state = LOADED;
                                        m->error = 0;
@@ -647,17 +649,24 @@ static int load_modprobe(void)
                                        continue;
                                }
 
-                               if (++m->error > 1)
-                                       ULOG_ERR("failed to load %s\n", m->name);
+                               m->error = 1;
                        }
 
-                       if ((m->state == PROBE) || m->error)
-                               todo++;
+                       if (m->error)
+                               failed++;
+                       else if (m->state == PROBE)
+                               skipped++;
                }
-               iterations++;
-       } while (loaded);
 
-       return todo;
+               if (allow_load_retry) {
+                       /* if we can't load anything else let's try to load failed modules */
+                       load_retry = loaded ? (failed && !skipped) : (failed && !load_retry && !first_iteration);
+               }
+
+               first_iteration = false;
+       } while (loaded || load_retry);
+
+       return skipped + failed;
 }
 
 static int print_insmod_usage(void)
@@ -886,7 +895,7 @@ static int main_modprobe(int argc, char **argv)
 
                m->state = PROBE;
 
-               fail = load_modprobe();
+               fail = load_modprobe(true);
 
                if (fail) {
                        ULOG_ERR("%d module%s could not be probed\n",
@@ -974,14 +983,14 @@ static int main_loader(int argc, char **argv)
                                m->opts = strdup(opts);
                        m->state = PROBE;
                        if (basename(gl.gl_pathv[j])[0] - '0' <= 9)
-                               load_modprobe();
+                               load_modprobe(false);
 
                }
                free(mod);
                fclose(fp);
        }
 
-       fail = load_modprobe();
+       fail = load_modprobe(true);
 
        if (fail) {
                ULOG_ERR("%d module%s could not be probed\n",