Messages in this thread Patch in this message | | | Subject | [PATCH] exit: Clarify choice of new parent in forget_original_parent() | From | Kirill Tkhai <> | Date | Tue, 16 Jun 2015 12:49:54 +0300 |
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Second parameter of find_new_reaper() and the similarity of its name and find_child_reaper()'s name confuse a reader.
Rename find_child_reaper() for better conformity of its name and its function. Also delete the second parameter of find_new_reaper().
These both improve modularity.
Signed-off-by: Kirill Tkhai <ktkhai@odin.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> --- kernel/exit.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/kernel/exit.c b/kernel/exit.c index 22fcc05..ae60a4d 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -450,7 +450,7 @@ static struct task_struct *find_alive_thread(struct task_struct *p) return NULL; } -static struct task_struct *find_child_reaper(struct task_struct *father) +static void exit_pidns_child_reaper(struct task_struct *father) __releases(&tasklist_lock) __acquires(&tasklist_lock) { @@ -458,12 +458,12 @@ static struct task_struct *find_child_reaper(struct task_struct *father) struct task_struct *reaper = pid_ns->child_reaper; if (likely(reaper != father)) - return reaper; + return; reaper = find_alive_thread(father); if (reaper) { pid_ns->child_reaper = reaper; - return reaper; + return; } write_unlock_irq(&tasklist_lock); @@ -473,8 +473,6 @@ static struct task_struct *find_child_reaper(struct task_struct *father) } zap_pid_ns_processes(pid_ns); write_lock_irq(&tasklist_lock); - - return father; } /* @@ -484,15 +482,21 @@ static struct task_struct *find_child_reaper(struct task_struct *father) * child_subreaper for its children (like a service manager) * 3. give it to the init process (PID 1) in our pid namespace */ -static struct task_struct *find_new_reaper(struct task_struct *father, - struct task_struct *child_reaper) +static struct task_struct *find_new_reaper(struct task_struct *father) { - struct task_struct *thread, *reaper; + struct task_struct *thread, *reaper, *child_reaper; thread = find_alive_thread(father); if (thread) return thread; + child_reaper = task_active_pid_ns(father)->child_reaper; + /* + * child_reaper doesn't have children after zap_pid_ns_processes(), + * therefore it can't enter this function. + */ + BUG_ON(child_reaper == father); + if (father->signal->has_child_subreaper) { /* * Find the first ->is_child_subreaper ancestor in our pid_ns. @@ -557,11 +561,11 @@ static void forget_original_parent(struct task_struct *father, exit_ptrace(father, dead); /* Can drop and reacquire tasklist_lock */ - reaper = find_child_reaper(father); + exit_pidns_child_reaper(father); if (list_empty(&father->children)) return; - reaper = find_new_reaper(father, reaper); + reaper = find_new_reaper(father); list_for_each_entry(p, &father->children, sibling) { for_each_thread(p, t) { t->real_parent = reaper;
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