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cgroup: Homogenize cgroup_get_from_id() return value

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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 d4ccaf58a8 ("bpf: Introduce cgroup
iter") that would use NULL instead of proper error handling in
d4ccaf58a8 ("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: d4ccaf58a8 ("bpf: Introduce cgroup iter")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Michal Koutný 2022-08-26 18:52:37 +02:00 committed by Tejun Heo
parent 4534dee941
commit fa7e439cf9
4 changed files with 6 additions and 11 deletions
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4
block/blk-cgroup-fc-appid.c
View File

@ -19,8 +19,8 @@ int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
return -EINVAL; return -EINVAL;
cgrp = cgroup_get_from_id(cgrp_id); cgrp = cgroup_get_from_id(cgrp_id);
if (!cgrp) if (IS_ERR(cgrp))
return -ENOENT; return PTR_ERR(cgrp);
css = cgroup_get_e_css(cgrp, &io_cgrp_subsys); css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
if (!css) { if (!css) {
ret = -ENOENT; ret = -ENOENT;

5
include/linux/cgroup.h
View File

@ -750,11 +750,6 @@ static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) 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 */ #endif /* !CONFIG_CGROUPS */
#ifdef CONFIG_CGROUPS #ifdef CONFIG_CGROUPS

4
kernel/cgroup/cgroup.c
View File

@ -6005,7 +6005,7 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
/* /*
* cgroup_get_from_id : get the cgroup associated with cgroup id * cgroup_get_from_id : get the cgroup associated with cgroup id
* @id: 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. * Only cgroups within current task's cgroup NS are valid.
*/ */
struct cgroup *cgroup_get_from_id(u64 id) struct cgroup *cgroup_get_from_id(u64 id)
@ -6037,7 +6037,7 @@ struct cgroup *cgroup_get_from_id(u64 id)
cgrp = NULL; cgrp = NULL;
} }
out: out:
return cgrp; return cgrp ?: ERR_PTR(-ENOENT);
} }
EXPORT_SYMBOL_GPL(cgroup_get_from_id); EXPORT_SYMBOL_GPL(cgroup_get_from_id);

4
mm/memcontrol.c
View File

@ -5110,8 +5110,8 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
struct mem_cgroup *memcg; struct mem_cgroup *memcg;
cgrp = cgroup_get_from_id(ino); cgrp = cgroup_get_from_id(ino);
if (!cgrp) if (IS_ERR(cgrp))
return ERR_PTR(-ENOENT); return PTR_ERR(cgrp);
css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys); css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
if (css) if (css)