From: Tejun Heo <tj@kernel.org>
Date: Fri, 28 Dec 2018 02:05:30 +0000 (-0800)
Subject: Merge branch 'for-4.20-fixes' into for-4.21
X-Git-Tag: v5.0-rc1~90^2~2
X-Git-Url: https://repo.jachan.dev/linux.git/commitdiff_plain/4d71c6f8771a6bccb844244f09831fa4624b22c1?hp=-c

Merge branch 'for-4.20-fixes' into for-4.21
---

4d71c6f8771a6bccb844244f09831fa4624b22c1
diff --combined kernel/cgroup/cgroup.c
index e06994fd4e34,1f84977fab47..8da9bf5e422f
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@@ -86,7 -86,6 +86,7 @@@ EXPORT_SYMBOL_GPL(css_set_lock)
  
  DEFINE_SPINLOCK(trace_cgroup_path_lock);
  char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
 +bool cgroup_debug __read_mostly;
  
  /*
   * Protects cgroup_idr and css_idr so that IDs can be released without
@@@ -1400,15 -1399,12 +1400,15 @@@ static char *cgroup_file_name(struct cg
  	struct cgroup_subsys *ss = cft->ss;
  
  	if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
 -	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX))
 -		snprintf(buf, CGROUP_FILE_NAME_MAX, "%s.%s",
 -			 cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
 +	    !(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
 +		const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : "";
 +
 +		snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
 +			 dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
  			 cft->name);
 -	else
 +	} else {
  		strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
 +	}
  	return buf;
  }
  
@@@ -3643,8 -3639,7 +3643,8 @@@ restart
  			continue;
  		if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
  			continue;
 -
 +		if ((cft->flags & CFTYPE_DEBUG) && !cgroup_debug)
 +			continue;
  		if (is_add) {
  			ret = cgroup_add_file(css, cgrp, cft);
  			if (ret) {
@@@ -4207,20 -4202,25 +4207,25 @@@ static void css_task_iter_advance(struc
  
  	lockdep_assert_held(&css_set_lock);
  repeat:
- 	/*
- 	 * Advance iterator to find next entry.  cset->tasks is consumed
- 	 * first and then ->mg_tasks.  After ->mg_tasks, we move onto the
- 	 * next cset.
- 	 */
- 	next = it->task_pos->next;
+ 	if (it->task_pos) {
+ 		/*
+ 		 * Advance iterator to find next entry.  cset->tasks is
+ 		 * consumed first and then ->mg_tasks.  After ->mg_tasks,
+ 		 * we move onto the next cset.
+ 		 */
+ 		next = it->task_pos->next;
  
- 	if (next == it->tasks_head)
- 		next = it->mg_tasks_head->next;
+ 		if (next == it->tasks_head)
+ 			next = it->mg_tasks_head->next;
  
- 	if (next == it->mg_tasks_head)
+ 		if (next == it->mg_tasks_head)
+ 			css_task_iter_advance_css_set(it);
+ 		else
+ 			it->task_pos = next;
+ 	} else {
+ 		/* called from start, proceed to the first cset */
  		css_task_iter_advance_css_set(it);
- 	else
- 		it->task_pos = next;
+ 	}
  
  	/* if PROCS, skip over tasks which aren't group leaders */
  	if ((it->flags & CSS_TASK_ITER_PROCS) && it->task_pos &&
@@@ -4260,7 -4260,7 +4265,7 @@@ void css_task_iter_start(struct cgroup_
  
  	it->cset_head = it->cset_pos;
  
- 	css_task_iter_advance_css_set(it);
+ 	css_task_iter_advance(it);
  
  	spin_unlock_irq(&css_set_lock);
  }
@@@ -5748,16 -5748,6 +5753,16 @@@ static int __init cgroup_disable(char *
  }
  __setup("cgroup_disable=", cgroup_disable);
  
 +void __init __weak enable_debug_cgroup(void) { }
 +
 +static int __init enable_cgroup_debug(char *str)
 +{
 +	cgroup_debug = true;
 +	enable_debug_cgroup();
 +	return 1;
 +}
 +__setup("cgroup_debug", enable_cgroup_debug);
 +
  /**
   * css_tryget_online_from_dir - get corresponding css from a cgroup dentry
   * @dentry: directory dentry of interest
@@@ -5993,8 -5983,10 +5998,8 @@@ static ssize_t show_delegatable_files(s
  
  		ret += snprintf(buf + ret, size - ret, "%s\n", cft->name);
  
 -		if (unlikely(ret >= size)) {
 -			WARN_ON(1);
 +		if (WARN_ON(ret >= size))
  			break;
 -		}
  	}
  
  	return ret;