cgroup: replace explicit ss_mask checking with for_each_subsys_which

Replace the explicit checking against ss_masks inside a for_each_subsys
block with for_each_subsys_which(..., ss_mask), to take advantage of the
more readable (and more efficient) macro.

Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 3a973519068ff5fa98989f43608fcd1ff9aa21c1..6d6d3c75209645dd75f2239f580234127aabdde9 100644 (file)
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1106,9 +1106,8 @@ static unsigned long cgroup_calc_child_subsys_mask(struct cgroup *cgrp,
        while (true) {
                unsigned long new_ss_mask = cur_ss_mask;
 
-               for_each_subsys(ss, ssid)
-                       if (cur_ss_mask & (1 << ssid))
-                               new_ss_mask |= ss->depends_on;
+               for_each_subsys_which(ss, ssid, &cur_ss_mask)
+                       new_ss_mask |= ss->depends_on;
 
                /*
                 * Mask out subsystems which aren't available.  This can
@@ -1246,10 +1245,7 @@ static int rebind_subsystems(struct cgroup_root *dst_root,
 
        lockdep_assert_held(&cgroup_mutex);
 
-       for_each_subsys(ss, ssid) {
-               if (!(ss_mask & (1 << ssid)))
-                       continue;
-
+       for_each_subsys_which(ss, ssid, &ss_mask) {
                /* if @ss has non-root csses attached to it, can't move */
                if (css_next_child(NULL, cgroup_css(&ss->root->cgrp, ss)))
                        return -EBUSY;
@@ -1286,18 +1282,14 @@ static int rebind_subsystems(struct cgroup_root *dst_root,
         * Nothing can fail from this point on.  Remove files for the
         * removed subsystems and rebind each subsystem.
         */
-       for_each_subsys(ss, ssid)
-               if (ss_mask & (1 << ssid))
-                       cgroup_clear_dir(&ss->root->cgrp, 1 << ssid);
+       for_each_subsys_which(ss, ssid, &ss_mask)
+               cgroup_clear_dir(&ss->root->cgrp, 1 << ssid);
 
-       for_each_subsys(ss, ssid) {
+       for_each_subsys_which(ss, ssid, &ss_mask) {
                struct cgroup_root *src_root;
                struct cgroup_subsys_state *css;
                struct css_set *cset;
 
-               if (!(ss_mask & (1 << ssid)))
-                       continue;
-
                src_root = ss->root;
                css = cgroup_css(&src_root->cgrp, ss);
 
@@ -2556,13 +2548,11 @@ static void cgroup_print_ss_mask(struct seq_file *seq, unsigned long ss_mask)
        bool printed = false;
        int ssid;
 
-       for_each_subsys(ss, ssid) {
-               if (ss_mask & (1 << ssid)) {
-                       if (printed)
-                               seq_putc(seq, ' ');
-                       seq_printf(seq, "%s", ss->name);
-                       printed = true;
-               }
+       for_each_subsys_which(ss, ssid, &ss_mask) {
+               if (printed)
+                       seq_putc(seq, ' ');
+               seq_printf(seq, "%s", ss->name);
+               printed = true;
        }
        if (printed)
                seq_putc(seq, '\n');
@@ -2704,11 +2694,12 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
         */
        buf = strstrip(buf);
        while ((tok = strsep(&buf, " "))) {
+               unsigned long tmp_ss_mask = ~cgrp_dfl_root_inhibit_ss_mask;
+
                if (tok[0] == '\0')
                        continue;
-               for_each_subsys(ss, ssid) {
-                       if (ss->disabled || strcmp(tok + 1, ss->name) ||
-                           ((1 << ss->id) & cgrp_dfl_root_inhibit_ss_mask))
+               for_each_subsys_which(ss, ssid, &tmp_ss_mask) {
+                       if (ss->disabled || strcmp(tok + 1, ss->name))
                                continue;
 
                        if (*tok == '+') {
@@ -2795,10 +2786,7 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
         * still around.  In such cases, wait till it's gone using
         * offline_waitq.
         */
-       for_each_subsys(ss, ssid) {
-               if (!(css_enable & (1 << ssid)))
-                       continue;
-
+       for_each_subsys_which(ss, ssid, &css_enable) {
                cgroup_for_each_live_child(child, cgrp) {
                        DEFINE_WAIT(wait);