From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH cgroup/for-6.1] cgroup: Make cgroup_get_from_id() prettier Date: Fri, 23 Sep 2022 07:31:58 -1000 Message-ID: References: <20220923115119.2035603-1-ming.lei@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc:subject:date; bh=1j5Ql9rL37iPMOSlhnWDpxhkWzpqM9TX0V/l3pD1H2A=; b=igB1iPgGCLD9KZEhspvQpefRM95eLmbd+I+sv8MaBi0Qbu/C6e7757NtMD2t9UliqK fjuGtfGRfw5/7i0+/vTbW/fF/gaX61Fkyw5IW8VxEzzSBMx8rmRr85zlUUuxDwKWHEb5 4hjxNbzZpQiX5xNrGkS+2vjHUkQSrweCDOTCIHEjw1Dbx81roj0glg251TxbPb/cur+B BmGCFScBEbv+3e0KEwgb9LnKiZmaEe/2S7EyMl5UP5P4/oVOLdKDa2+QedQtOxc3877j C8gA8VcoHOk4i6APPIREhKmky+C+FL9ELvrR0xej0a2ewf2pSesszorvo9VctdIqoV1b 03kg== Sender: Tejun Heo Content-Disposition: inline In-Reply-To: List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Ming Lei Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Marco Patalano , Muneendra , Michal =?iso-8859-1?Q?Koutn=FD?= >From 7e1eb5437d3c3fdb61d45378579aab383cafc694 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 23 Sep 2022 07:23:06 -1000 MIME-Version: 1.0 Content-Type: text/plain; charset=3DUTF-8 Content-Transfer-Encoding: 8bit After merging 836ac87d ("cgroup: fix cgroup_get_from_id") into for-6.1, its combination with two commits in for-6.1 - 4534dee9 ("cgroup: cgroup: Honor caller's cgroup NS when resolving cgroup id") and fa7e439c ("cgroup: Homogenize cgroup_get_from_id() return value") - makes the gotos in the error handling path too ugly while not adding anything of value. All that the gotos are saving is one extra kernfs_put() call. Let's remove the gotos and perform error returns directly. Signed-off-by: Tejun Heo Cc: Ming Lei Cc: Michal Koutn=FD --- Hello, Ming, Michal, you guys' changes to cgroup_get_from_id() combine to make cgroup_get_from_id() a bit too ugly, so I applied the following patch to cgroup/for-6.1. Please take a look and lemme know if I broke anything. Thanks. kernel/cgroup/cgroup.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 0d93cd17548c..c1f1ef6090da 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -6066,14 +6066,16 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, = size_t buflen) struct cgroup *cgroup_get_from_id(u64 id) { struct kernfs_node *kn; - struct cgroup *cgrp =3D NULL, *root_cgrp; + struct cgroup *cgrp, *root_cgrp; =20 kn =3D kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id); if (!kn) - goto out; + return ERR_PTR(-ENOENT); =20 - if (kernfs_type(kn) !=3D KERNFS_DIR) - goto put; + if (kernfs_type(kn) !=3D KERNFS_DIR) { + kernfs_put(kn); + return ERR_PTR(-ENOENT); + } =20 rcu_read_lock(); =20 @@ -6082,21 +6084,20 @@ struct cgroup *cgroup_get_from_id(u64 id) cgrp =3D NULL; =20 rcu_read_unlock(); -put: kernfs_put(kn); =20 if (!cgrp) - goto out; + return ERR_PTR(-ENOENT); =20 spin_lock_irq(&css_set_lock); root_cgrp =3D current_cgns_cgroup_from_root(&cgrp_dfl_root); spin_unlock_irq(&css_set_lock); if (!cgroup_is_descendant(cgrp, root_cgrp)) { cgroup_put(cgrp); - cgrp =3D NULL; + return ERR_PTR(-ENOENT); } -out: - return cgrp ?: ERR_PTR(-ENOENT); + + return cgrp; } EXPORT_SYMBOL_GPL(cgroup_get_from_id); =20 --=20 2.37.3