From edfcf0c638fd4c7988e833989fca9167d079674e Mon Sep 17 00:00:00 2001
From: Michal Koutný <mkoutny@suse.com>
Date: May 29 2023 13:51:35 +0000
Subject: cgroup: Homogenize cgroup_get_from_id() return value

(bsc#1205650).

---

diff --git a/patches.suse/cgroup-Homogenize-cgroup_get_from_id-return-value.patch b/patches.suse/cgroup-Homogenize-cgroup_get_from_id-return-value.patch
new file mode 100644
index 0000000..b75a2e2
--- /dev/null
+++ b/patches.suse/cgroup-Homogenize-cgroup_get_from_id-return-value.patch
@@ -0,0 +1,80 @@
+From: =?utf-8?b?TWljaGFsIEtvdXRuw70gPG1rb3V0bnlAc3VzZS5jb20+?=
+Date: Fri, 26 Aug 2022 18:52:37 +0200
+Subject: cgroup: Homogenize cgroup_get_from_id() return value
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+Git-commit: fa7e439cf90ba23ea473d0b7d85efd02ae6ccf94
+Patch-mainline: v6.1-rc1
+References: bsc#1205650
+
+Cgroup id is user provided datum hence extend its return domain to
+include possible error reason (similar to cgroup_get_from_fd()).
+
+This change also fixes commit d4ccaf58a847 ("bpf: Introduce cgroup
+iter") that would use NULL instead of proper error handling in
+d4ccaf58a847 ("bpf: Introduce cgroup iter").
+
+Additionally, neither of: fc_appid_store, bpf_iter_attach_cgroup,
+mem_cgroup_get_from_ino (callers of cgroup_get_from_fd) is built without
+CONFIG_CGROUPS (depends via CONFIG_BLK_CGROUP, direct, transitive
+CONFIG_MEMCG respectively) transitive, so drop the singular definition
+not needed with !CONFIG_CGROUPS.
+
+Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter")
+Signed-off-by: Michal Koutný <mkoutny@suse.com>
+Signed-off-by: Tejun Heo <tj@kernel.org>
+[mkoutny: drop mem_cgroup_get_from_ino() hunk]
+---
+ block/blk-cgroup-fc-appid.c |    4 ++--
+ include/linux/cgroup.h      |    5 -----
+ kernel/cgroup/cgroup.c      |    4 ++--
+ 3 files changed, 4 insertions(+), 9 deletions(-)
+
+--- a/block/blk-cgroup-fc-appid.c
++++ b/block/blk-cgroup-fc-appid.c
+@@ -19,8 +19,8 @@ int blkcg_set_fc_appid(char *app_id, u64
+ 		return -EINVAL;
+ 
+ 	cgrp = cgroup_get_from_id(cgrp_id);
+-	if (!cgrp)
+-		return -ENOENT;
++	if (IS_ERR(cgrp))
++		return PTR_ERR(cgrp);
+ 	css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
+ 	if (!css) {
+ 		ret = -ENOENT;
+--- a/include/linux/cgroup.h
++++ b/include/linux/cgroup.h
+@@ -751,11 +751,6 @@ static inline bool task_under_cgroup_hie
+ 
+ static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
+ {}
+-
+-static inline struct cgroup *cgroup_get_from_id(u64 id)
+-{
+-	return NULL;
+-}
+ #endif /* !CONFIG_CGROUPS */
+ 
+ #ifdef CONFIG_CGROUPS
+--- a/kernel/cgroup/cgroup.c
++++ b/kernel/cgroup/cgroup.c
+@@ -6002,7 +6002,7 @@ void cgroup_path_from_kernfs_id(u64 id,
+ /*
+  * cgroup_get_from_id : get the cgroup associated with cgroup id
+  * @id: cgroup id
+- * On success return the cgrp, on failure return NULL
++ * On success return the cgrp or ERR_PTR on failure
+  * Only cgroups within current task's cgroup NS are valid.
+  */
+ struct cgroup *cgroup_get_from_id(u64 id)
+@@ -6038,7 +6038,7 @@ put:
+ 		cgrp = NULL;
+ 	}
+ out:
+-	return cgrp;
++	return cgrp ?: ERR_PTR(-ENOENT);
+ }
+ EXPORT_SYMBOL_GPL(cgroup_get_from_id);
+ 
diff --git a/series.conf b/series.conf
index 6dc2ae9..30a9dd1 100644
--- a/series.conf
+++ b/series.conf
@@ -16708,6 +16708,7 @@
 	patches.suse/locking-rwsem-Disable-preemption-while-trying-for-rw.patch
 	patches.suse/cgroup-Honor-caller-s-cgroup-NS-when-resolving-path.patch
 	patches.suse/cgroup-cgroup-Honor-caller-s-cgroup-NS-when-resolving-cgroup-id.patch
+	patches.suse/cgroup-Homogenize-cgroup_get_from_id-return-value.patch
 	patches.suse/cgroup-cpuset-Enable-update_tasks_cpumask-on-top_cpuset.patch
 	patches.suse/livepatch-fix-race-between-fork-and-KLP-transition.patch
 	patches.suse/livepatch-Add-a-missing-newline-character-in-klp_mod.patch