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Commit 5faaf05f authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: Explicitly remove core interface files 



The "cgroup." core interface files bypass the usual interface removal
path and get removed recursively along with the cgroup itself.  While
this works now, the subtle discrepancy gets in the way of implementing
common mechanisms.

This patch updates cgroup core interface file handling so that it's
consistent with controller interface files.  When added, the css is
marked CSS_VISIBLE and they're explicitly removed before the cgroup is
destroyed.

This doesn't cause user-visible behavior changes.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent fe03a759

kernel/cgroup/cgroup.c

+22 −13
Original line number Diff line number Diff line
@@ -1573,9 +1573,18 @@ static void css_clear_dir(struct cgroup_subsys_state *css) 


	css->flags &= ~CSS_VISIBLE;



	if (!css->ss) {

		if (cgroup_on_dfl(cgrp))

			cfts = cgroup_base_files;

		else

			cfts = cgroup1_base_files;



		cgroup_addrm_files(css, cgrp, cfts, false);

	} else {

		list_for_each_entry(cfts, &css->ss->cfts, node)

			cgroup_addrm_files(css, cgrp, cfts, false);

	}

}



/**

 * css_populate_dir - create subsys files in a cgroup directory
@@ -1598,9 +1607,10 @@ static int css_populate_dir(struct cgroup_subsys_state *css) 
		else

			cfts = cgroup1_base_files;



		return cgroup_addrm_files(&cgrp->self, cgrp, cfts, true);

	}



		ret = cgroup_addrm_files(&cgrp->self, cgrp, cfts, true);

		if (ret < 0)

			return ret;

	} else {

		list_for_each_entry(cfts, &css->ss->cfts, node) {

			ret = cgroup_addrm_files(css, cgrp, cfts, true);

			if (ret < 0) {
@@ -1608,6 +1618,7 @@ static int css_populate_dir(struct cgroup_subsys_state *css) 
				goto err;

			}

		}

	}



	css->flags |= CSS_VISIBLE;
@@ -5090,10 +5101,8 @@ static int cgroup_destroy_locked(struct cgroup *cgrp) 
	for_each_css(css, ssid, cgrp)

		kill_css(css);



	/*

	 * Remove @cgrp directory along with the base files.  @cgrp has an

	 * extra ref on its kn.

	 */

	/* clear and remove @cgrp dir, @cgrp has an extra ref on its kn */

	css_clear_dir(&cgrp->self);

	kernfs_remove(cgrp->kn);



	if (parent && cgroup_is_threaded(cgrp))