[RFC PATCH 06/27] untangling ep_call_nested(): move push/pop of cookie into the callbacks

Al Viro
2020-10-04T02:41:03Z

fs/eventpoll.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index bd2cc78c47c8..9a6ee5991f3d 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -455,15 +455,7 @@ static bool ep_push_nested(void *cookie)
static int ep_call_nested(int (*nproc)(void *, void *, int), void *priv,
void *cookie)
{
- int error;
-
- if (!ep_push_nested(cookie))
- return -1;
- /* Call the nested function */
- error = (*nproc)(priv, cookie, nesting - 1);
- nesting--;
-
- return error;
+ return (*nproc)(priv, cookie, nesting);
}

/*
@@ -1340,6 +1332,9 @@ static int reverse_path_check_proc(void *priv, void *cookie, int call_nests)
struct file *child_file;
struct epitem *epi;

+ if (!ep_push_nested(cookie)) /* limits recursion */
+ return -1;
+
/* CTL_DEL can remove links here, but that can't increase our count */
rcu_read_lock();
list_for_each_entry_rcu(epi, &file->f_ep_links, fllink) {
@@ -1362,6 +1357,7 @@ static int reverse_path_check_proc(void *priv, void *cookie, int call_nests)
}
}
rcu_read_unlock();
+ nesting--; /* pop */
return error;
}

@@ -1913,6 +1909,9 @@ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests)
struct rb_node *rbp;
struct epitem *epi;

+ if (!ep_push_nested(cookie)) /* limits recursion */
+ return -1;
+
mutex_lock_nested(&ep->mtx, call_nests + 1);
ep->gen = loop_check_gen;
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
@@ -1942,6 +1941,7 @@ static int ep_loop_check_proc(void *priv, void *cookie, int call_nests)
}
}
mutex_unlock(&ep->mtx);
+ nesting--; /* pop */

return error;
}
--
2.11.0