modprobe: Add --wait

Retry module removal if it fails due to EAGAIN. This allows user to pass
--wait <timeout>, during which `modprobe -r` will keep trying to remove
the module.

Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>

diff --git a/man/modprobe.xml b/man/modprobe.xml
index 0372b6b23b87d9a5bbd4cfc2a5b4dc1fbc07e1a9..db39c7a18bb7c15cdbe04469e2e99bb8e77c0fc5 100644 (file)
--- a/man/modprobe.xml
+++ b/man/modprobe.xml
@@ -388,6 +388,23 @@
           </para>
         </listitem>
       </varlistentry>
+      <varlistentry>
+        <term>
+          <option>-w</option>
+        </term>
+        <term>
+        <option>--wait=</option>TIMEOUT_MSEC
+        </term>
+        <listitem>
+          <para>
+            This option causes <command>modprobe -r</command> to continue trying to
+            remove a module if it fails due to the module being busy, i.e. its refcount
+            is not 0 at the time the call is made. Modprobe tries to remove the module
+            with an incremental sleep time between each tentative up until the maximum
+            wait time in milliseconds passed in this option.
+          </para>
+        </listitem>
+      </varlistentry>
       <varlistentry>
         <term>
           <option>-S</option>

diff --git a/tools/modprobe.c b/tools/modprobe.c
index caaf87f443dbafcede18186868d2154026f36f8f..2a2ae21f537051cab47f433106277dec63583d9d 100644 (file)
--- a/tools/modprobe.c
+++ b/tools/modprobe.c
@@ -32,6 +32,7 @@
 #include <sys/wait.h>
 
 #include <shared/array.h>
+#include <shared/util.h>
 #include <shared/macro.h>
 
 #include <libkmod/libkmod.h>
@@ -55,14 +56,18 @@ static int force = 0;
 static int strip_modversion = 0;
 static int strip_vermagic = 0;
 static int remove_holders = 0;
+static unsigned long long wait_msec = 0;
 static int quiet_inuse = 0;
 
-static const char cmdopts_s[] = "arRibfDcnC:d:S:sqvVh";
+static const char cmdopts_s[] = "arw:RibfDcnC:d:S:sqvVh";
 static const struct option cmdopts[] = {
        {"all", no_argument, 0, 'a'},
+
        {"remove", no_argument, 0, 'r'},
        {"remove-dependencies", no_argument, 0, 5},
        {"remove-holders", no_argument, 0, 5},
+       {"wait", required_argument, 0, 'w'},
+
        {"resolve-alias", no_argument, 0, 'R'},
        {"first-time", no_argument, 0, 3},
        {"ignore-install", no_argument, 0, 'i'},
@@ -110,6 +115,9 @@ static void help(void)
                "\t-r, --remove                Remove modules instead of inserting\n"
                "\t    --remove-dependencies   Deprecated: use --remove-holders\n"
                "\t    --remove-holders        Also remove module holders (use together with -r)\n"
+               "\t-w, --wait <MSEC>           When removing a module, wait up to MSEC for\n"
+               "\t                            module's refcount to become 0 so it can be\n"
+               "\t                            removed (use together with -r)\n"
                "\t    --first-time            Fail if module already inserted or removed\n"
                "\t-i, --ignore-install        Ignore install commands\n"
                "\t-i, --ignore-remove         Ignore remove commands\n"
@@ -322,6 +330,8 @@ end:
 static int rmmod_do_remove_module(struct kmod_module *mod)
 {
        const char *modname = kmod_module_get_name(mod);
+       unsigned long long interval_msec = 0, t0_msec = 0,
+                     tend_msec = 0;
        int flags = 0, err;
 
        SHOW("rmmod %s\n", modname);
@@ -332,13 +342,45 @@ static int rmmod_do_remove_module(struct kmod_module *mod)
        if (force)
                flags |= KMOD_REMOVE_FORCE;
 
-       err = kmod_module_remove_module(mod, flags);
-       if (err == -EEXIST) {
-               if (!first_time)
-                       err = 0;
-               else
-                       LOG("Module %s is not in kernel.\n", modname);
-       }
+       if (wait_msec)
+               flags |= KMOD_REMOVE_NOLOG;
+
+       do {
+               err = kmod_module_remove_module(mod, flags);
+               if (err == -EEXIST) {
+                       if (!first_time)
+                               err = 0;
+                       else
+                               LOG("Module %s is not in kernel.\n", modname);
+                       break;
+               } else if (err == -EAGAIN && wait_msec) {
+                       unsigned long long until_msec;
+
+                       if (!t0_msec) {
+                               t0_msec = now_msec();
+                               tend_msec = t0_msec + wait_msec;
+                               interval_msec = 1;
+                       }
+
+                       until_msec = get_backoff_delta_msec(t0_msec, tend_msec,
+                                                         &interval_msec);
+                       err = sleep_until_msec(until_msec);
+
+                       if (!t0_msec)
+                               err = -ENOTSUP;
+
+                       if (err < 0) {
+                               ERR("Failed to sleep: %s\n", strerror(-err));
+                               err = -EAGAIN;
+                               break;
+                       }
+               } else {
+                       break;
+               }
+       } while (interval_msec);
+
+       if (err < 0 && wait_msec)
+               ERR("could not remove '%s': %s\n", modname, strerror(-err));
 
        return err;
 }
@@ -418,7 +460,7 @@ static int rmmod_do_module(struct kmod_module *mod, int flags)
        }
 
        /* 3. @mod itself, but check for refcnt first */
-       if (!cmd && !ignore_loaded) {
+       if (!cmd && !ignore_loaded && !wait_msec) {
                int usage = kmod_module_get_refcnt(mod);
 
                if (usage > 0) {
@@ -800,6 +842,16 @@ static int do_modprobe(int argc, char **orig_argv)
                case 5:
                        remove_holders = 1;
                        break;
+               case 'w': {
+                       char *endptr = NULL;
+                       wait_msec = strtoul(optarg, &endptr, 0);
+                       if (!*optarg || *endptr) {
+                               ERR("unexpected wait value '%s'.\n", optarg);
+                               err = -1;
+                               goto done;
+                       }
+                       break;
+               }
                case 3:
                        first_time = 1;
                        break;