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Commit b1f28d31 authored by Tejun Heo's avatar Tejun Heo
Browse files

cgroup: fix error path of cgroup_addrm_files() 



cgroup_addrm_files() mishandled error return value from
cgroup_add_file() and returns error iff the last file fails to create.
As we're in the process of cleaning up file add/rm error handling and
will reliably propagate file creation failures, there's no point in
keeping adding files after a failure.

Replace the broken error collection logic with immediate error return.
While at it, add lockdep assertions and function comment.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarLi Zefan <lizefan@huawei.com>
parent 8f89140a

kernel/cgroup.c

+22 −6
Original line number Diff line number Diff line
@@ -2780,11 +2780,26 @@ static int cgroup_add_file(struct cgroup *cgrp, struct cgroup_subsys *subsys, 
	return error;

}



/**

 * cgroup_addrm_files - add or remove files to a cgroup directory

 * @cgrp: the target cgroup

 * @subsys: the subsystem of files to be added

 * @cfts: array of cftypes to be added

 * @is_add: whether to add or remove

 *

 * Depending on @is_add, add or remove files defined by @cfts on @cgrp.

 * All @cfts should belong to @subsys.  For removals, this function never

 * fails.  If addition fails, this function doesn't remove files already

 * added.  The caller is responsible for cleaning up.

 */

static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys,

			      struct cftype cfts[], bool is_add)

{

	struct cftype *cft;

	int err, ret = 0;

	int ret;



	lockdep_assert_held(&cgrp->dentry->d_inode->i_mutex);

	lockdep_assert_held(&cgroup_mutex);



	for (cft = cfts; cft->name[0] != '\0'; cft++) {

		/* does cft->flags tell us to skip this file on @cgrp? */
@@ -2796,16 +2811,17 @@ static int cgroup_addrm_files(struct cgroup *cgrp, struct cgroup_subsys *subsys, 
			continue;



		if (is_add) {

			err = cgroup_add_file(cgrp, subsys, cft);

			if (err)

			ret = cgroup_add_file(cgrp, subsys, cft);

			if (ret) {

				pr_warn("cgroup_addrm_files: failed to add %s, err=%d\n",

					cft->name, err);

			ret = err;

					cft->name, ret);

				return ret;

			}

		} else {

			cgroup_rm_file(cgrp, cft);

		}

	}

	return ret;

	return 0;

}



static void cgroup_cfts_prepare(void)