nixos/kernel: Allow controlling modules with attrsets

Author: ElvishJerricco

lib/types.nix

@@ -1162,6 +1162,13 @@ rec {
         nestedTypes.finalType = finalType;
       };
 
+    # A list of attrnames is coerced into an attrset of bools by
+    # setting the values to true.
+    attrNamesToTrue = coercedTo
+      (types.listOf types.str)
+      (enabled: lib.listToAttrs (map (mod: lib.nameValuePair mod true) enabled))
+      (types.attrsOf types.bool);
+
     # Augment the given type with an additional type check function.
     addCheck = elemType: check: elemType // { check = x: elemType.check x && check x; };
 

nixos/doc/manual/development/option-types.section.md

@@ -135,6 +135,29 @@ merging is handled.
     problems.
     :::
 
+`types.attrNamesToTrue`
+
+:   Either a list of attribute names, or an attribute set of
+    booleans. A list will be coerced into an attribute set with those
+    names, whose values are set to `true`. This is useful when it is
+    convenient to be able to write definitions as a simple list, but
+    still need to be able to override and disable individual values.
+
+    ::: {#ex-types-attrNamesToTrue .example}
+    ### `types.attrNamesToTrue`
+    ```
+    {
+      foo = [ "bar" ];
+    }
+    ```
+    
+    ```
+    {
+      foo.bar = true;
+    }
+    ```
+    :::
+
 `types.pkgs`
 
 :   A type for the top level Nixpkgs package set.

nixos/modules/system/boot/kernel.nix

@@ -8,6 +8,14 @@ let
   inherit (config.boot.kernel) features randstructSeed;
   inherit (config.boot.kernelPackages) kernel;
 
+  modulesTypeDesc = ''
+    This can either be a list of modules, or an attrset. In an
+    attrset, names that are set to `true` represent modules that will
+    be included. Note that setting these names to `false` does not
+    prevent the module from being loaded. For that, use
+    {option}`boot.blacklistedKernelModules`.
+  '';
+
   kernelModulesConf = pkgs.writeText "nixos.conf"
     ''
       ${concatStringsSep "\n" config.boot.kernelModules}
@@ -175,20 +183,23 @@ in
     };
 
     boot.kernelModules = mkOption {
-      type = types.listOf types.str;
-      default = [];
+      type = types.attrNamesToTrue;
+      default = { };
       description = ''
         The set of kernel modules to be loaded in the second stage of
         the boot process.  Note that modules that are needed to
         mount the root file system should be added to
         {option}`boot.initrd.availableKernelModules` or
         {option}`boot.initrd.kernelModules`.
+
+        ${modulesTypeDesc}
       '';
+      apply = mods: lib.attrNames (lib.filterAttrs (_: v: v) mods);
     };
 
     boot.initrd.availableKernelModules = mkOption {
-      type = types.listOf types.str;
-      default = [];
+      type = types.attrNamesToTrue;
+      default = { };
       example = [ "sata_nv" "ext3" ];
       description = ''
         The set of kernel modules in the initial ramdisk used during the
@@ -204,13 +215,21 @@ in
         modules for PCI devices are loaded when they match the PCI ID
         of a device in your system).  To force a module to be loaded,
         include it in {option}`boot.initrd.kernelModules`.
+
+        ${modulesTypeDesc}
       '';
+      apply = mods: lib.attrNames (lib.filterAttrs (_: v: v) mods);
     };
 
     boot.initrd.kernelModules = mkOption {
-      type = types.listOf types.str;
-      default = [];
-      description = "List of modules that are always loaded by the initrd.";
+      type = types.attrNamesToTrue;
+      default = { };
+      description = ''
+        Set of modules that are always loaded by the initrd.
+
+        ${modulesTypeDesc}
+      '';
+      apply = mods: lib.attrNames (lib.filterAttrs (_: v: v) mods);
     };
 
     boot.initrd.includeDefaultModules = mkOption {

nixos/modules/system/boot/modprobe.nix

@@ -25,16 +25,19 @@ with lib;
       };
 
     boot.blacklistedKernelModules = mkOption {
-      type = types.listOf types.str;
-      default = [ ];
+      type = types.attrNamesToTrue;
+      default = { };
       example = [
         "cirrusfb"
         "i2c_piix4"
       ];
       description = ''
-        List of names of kernel modules that should not be loaded
-        automatically by the hardware probing code.
+        Set of names of kernel modules that should not be loaded
+        automatically by the hardware probing code. This can either be
+        a list of modules or an attrset. In an attrset, names that are
+        set to `true` represent modules that will be blacklisted.
       '';
+      apply = mods: lib.attrNames (lib.filterAttrs (_: v: v) mods);
     };
 
     boot.extraModprobeConfig = mkOption {

nixos/modules/tasks/filesystems.nix

@@ -273,10 +273,7 @@ in
           zfs = lib.mkForce false;
         }
       '';
-      type = types.coercedTo
-        (types.listOf types.str)
-        (enabled: lib.listToAttrs (map (fs: lib.nameValuePair fs true) enabled))
-        (types.attrsOf types.bool);
+      type = types.attrNamesToTrue;
       description = ''
         Names of supported filesystem types, or an attribute set of file system types
         and their state. The set form may be used together with `lib.mkForce` to