Commit bb1a1146 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cgroup-for-6.1-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup fixes from Tejun Heo:

 - Fix a recent regression where a sleeping kernfs function is called
   with css_set_lock (spinlock) held

 - Revert the commit to enable cgroup1 support for cgroup_get_from_fd/file()

   Multiple users assume that the lookup only works for cgroup2 and
   breaks when fed a cgroup1 file. Instead, introduce a separate set of
   functions to lookup both v1 and v2 and use them where the user
   explicitly wants to support both versions.

 - Compat update for tools/perf/util/bpf_skel/bperf_cgroup.bpf.c.

 - Add Josef Bacik as a blkcg maintainer.

* tag 'cgroup-for-6.1-rc1-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  blkcg: Update MAINTAINERS entry
  mm: cgroup: fix comments for get from fd/file helpers
  perf stat: Support old kernels for bperf cgroup counting
  bpf: cgroup_iter: support cgroup1 using cgroup fd
  cgroup: add cgroup_v1v2_get_from_[fd/file]()
  Revert "cgroup: enable cgroup_get_from_file() on cgroup1"
  cgroup: Reorganize css_set_lock and kernfs path processing
parents bbb8ceb5 79a818b5

MAINTAINERS

+2 −0
Original line number Diff line number Diff line
@@ -5266,6 +5266,7 @@ F: tools/testing/selftests/cgroup/ 








CONTROL GROUP - BLOCK IO CONTROLLER (BLKIO)









M:	Tejun Heo <tj@kernel.org>









M:	Josef Bacik <josef@toxicpanda.com>









M:	Jens Axboe <axboe@kernel.dk>









L:	cgroups@vger.kernel.org









L:	linux-block@vger.kernel.org








@@ -5273,6 +5274,7 @@ T:	git git://git.kernel.dk/linux-block







F:	Documentation/admin-guide/cgroup-v1/blkio-controller.rst









F:	block/bfq-cgroup.c









F:	block/blk-cgroup.c









F:	block/blk-iocost.c









F:	block/blk-iolatency.c









F:	block/blk-throttle.c









F:	include/linux/blk-cgroup.h
































include/linux/cgroup.h



+1
−0






























Original line number
Diff line number
Diff line







@@ -106,6 +106,7 @@ struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,

















struct cgroup *cgroup_get_from_path(const char *path);









struct cgroup *cgroup_get_from_fd(int fd);









struct cgroup *cgroup_v1v2_get_from_fd(int fd);



















int cgroup_attach_task_all(struct task_struct *from, struct task_struct *);









int cgroup_transfer_tasks(struct cgroup *to, struct cgroup *from);
































kernel/bpf/cgroup_iter.c



+1
−1






























Original line number
Diff line number
Diff line







@@ -196,7 +196,7 @@ static int bpf_iter_attach_cgroup(struct bpf_prog *prog,







		return -EINVAL;



















	if (fd)









		cgrp = cgroup_get_from_fd(fd);









		cgrp = cgroup_v1v2_get_from_fd(fd);









	else if (id)









		cgrp = cgroup_get_from_id(id);









	else /* walk the entire hierarchy by default. */
































kernel/cgroup/cgroup.c



+79
−20






























Original line number
Diff line number
Diff line







@@ -1392,6 +1392,9 @@ static void cgroup_destroy_root(struct cgroup_root *root)







	cgroup_free_root(root);









}



















/*









 * Returned cgroup is without refcount but it's valid as long as cset pins it.









 */









static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,









					    struct cgroup_root *root)









{








@@ -1403,6 +1406,7 @@ static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,







		res_cgroup = cset->dfl_cgrp;









	} else {









		struct cgrp_cset_link *link;









		lockdep_assert_held(&css_set_lock);



















		list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {









			struct cgroup *c = link->cgrp;








@@ -1414,6 +1418,7 @@ static inline struct cgroup *__cset_cgroup_from_root(struct css_set *cset,







		}









	}



















	BUG_ON(!res_cgroup);









	return res_cgroup;









}


















@@ -1436,23 +1441,36 @@ current_cgns_cgroup_from_root(struct cgroup_root *root)

















	rcu_read_unlock();



















	BUG_ON(!res);









	return res;









}



















/*









 * Look up cgroup associated with current task's cgroup namespace on the default









 * hierarchy.









 *









 * Unlike current_cgns_cgroup_from_root(), this doesn't need locks:









 * - Internal rcu_read_lock is unnecessary because we don't dereference any rcu









 *   pointers.









 * - css_set_lock is not needed because we just read cset->dfl_cgrp.









 * - As a bonus returned cgrp is pinned with the current because it cannot









 *   switch cgroup_ns asynchronously.









 */









static struct cgroup *current_cgns_cgroup_dfl(void)









{









	struct css_set *cset;



















	cset = current->nsproxy->cgroup_ns->root_cset;









	return __cset_cgroup_from_root(cset, &cgrp_dfl_root);









}



















/* look up cgroup associated with given css_set on the specified hierarchy */









static struct cgroup *cset_cgroup_from_root(struct css_set *cset,









					    struct cgroup_root *root)









{









	struct cgroup *res = NULL;



















	lockdep_assert_held(&cgroup_mutex);









	lockdep_assert_held(&css_set_lock);



















	res = __cset_cgroup_from_root(cset, root);



















	BUG_ON(!res);









	return res;









	return __cset_cgroup_from_root(cset, root);









}



















/*








@@ -6191,9 +6209,7 @@ struct cgroup *cgroup_get_from_id(u64 id)







	if (!cgrp)









		return ERR_PTR(-ENOENT);



















	spin_lock_irq(&css_set_lock);









	root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root);









	spin_unlock_irq(&css_set_lock);









	root_cgrp = current_cgns_cgroup_dfl();









	if (!cgroup_is_descendant(cgrp, root_cgrp)) {









		cgroup_put(cgrp);









		return ERR_PTR(-ENOENT);








@@ -6294,16 +6310,42 @@ void cgroup_fork(struct task_struct *child)







	INIT_LIST_HEAD(&child->cg_list);









}



















static struct cgroup *cgroup_get_from_file(struct file *f)









/**









 * cgroup_v1v2_get_from_file - get a cgroup pointer from a file pointer









 * @f: file corresponding to cgroup_dir









 *









 * Find the cgroup from a file pointer associated with a cgroup directory.









 * Returns a pointer to the cgroup on success. ERR_PTR is returned if the









 * cgroup cannot be found.









 */









static struct cgroup *cgroup_v1v2_get_from_file(struct file *f)









{









	struct cgroup_subsys_state *css;









	struct cgroup *cgrp;



















	css = css_tryget_online_from_dir(f->f_path.dentry, NULL);









	if (IS_ERR(css))









		return ERR_CAST(css);



















	cgrp = css->cgroup;









	return css->cgroup;









}



















/**









 * cgroup_get_from_file - same as cgroup_v1v2_get_from_file, but only supports









 * cgroup2.









 * @f: file corresponding to cgroup2_dir









 */









static struct cgroup *cgroup_get_from_file(struct file *f)









{









	struct cgroup *cgrp = cgroup_v1v2_get_from_file(f);



















	if (IS_ERR(cgrp))









		return ERR_CAST(cgrp);



















	if (!cgroup_on_dfl(cgrp)) {









		cgroup_put(cgrp);









		return ERR_PTR(-EBADF);









	}



















	return cgrp;









}


















@@ -6772,10 +6814,8 @@ struct cgroup *cgroup_get_from_path(const char *path)







	struct cgroup *cgrp = ERR_PTR(-ENOENT);









	struct cgroup *root_cgrp;



















	spin_lock_irq(&css_set_lock);









	root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root);









	root_cgrp = current_cgns_cgroup_dfl();









	kn = kernfs_walk_and_get(root_cgrp->kn, path);









	spin_unlock_irq(&css_set_lock);









	if (!kn)









		goto out;


















@@ -6800,15 +6840,15 @@ struct cgroup *cgroup_get_from_path(const char *path)







EXPORT_SYMBOL_GPL(cgroup_get_from_path);



















/**









 * cgroup_get_from_fd - get a cgroup pointer from a fd









 * @fd: fd obtained by open(cgroup2_dir)









 * cgroup_v1v2_get_from_fd - get a cgroup pointer from a fd









 * @fd: fd obtained by open(cgroup_dir)









 *









 * Find the cgroup from a fd which should be obtained









 * by opening a cgroup directory.  Returns a pointer to the









 * cgroup on success. ERR_PTR is returned if the cgroup









 * cannot be found.









 */









struct cgroup *cgroup_get_from_fd(int fd)









struct cgroup *cgroup_v1v2_get_from_fd(int fd)









{









	struct cgroup *cgrp;









	struct file *f;








@@ -6817,10 +6857,29 @@ struct cgroup *cgroup_get_from_fd(int fd)







	if (!f)









		return ERR_PTR(-EBADF);



















	cgrp = cgroup_get_from_file(f);









	cgrp = cgroup_v1v2_get_from_file(f);









	fput(f);









	return cgrp;









}



















/**









 * cgroup_get_from_fd - same as cgroup_v1v2_get_from_fd, but only supports









 * cgroup2.









 * @fd: fd obtained by open(cgroup2_dir)









 */









struct cgroup *cgroup_get_from_fd(int fd)









{









	struct cgroup *cgrp = cgroup_v1v2_get_from_fd(fd);



















	if (IS_ERR(cgrp))









		return ERR_CAST(cgrp);



















	if (!cgroup_on_dfl(cgrp)) {









		cgroup_put(cgrp);









		return ERR_PTR(-EBADF);









	}









	return cgrp;









}









EXPORT_SYMBOL_GPL(cgroup_get_from_fd);



















static u64 power_of_ten(int power)