[RFC PATCH 13/27] ep_loop_check_proc(): saner calling conventions

Al Viro
2020-10-04T02:39:59Z

1) 'cookie' argument is unused; kill it.
2) 'priv' one is always an epoll struct file, and we only care
about its associated struct eventpoll; pass that instead.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/eventpoll.c | 38 ++++++++++++++++----------------------
1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 6b1990b8b9a0..e971e3ace557 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1845,19 +1845,14 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
* result in excessive stack usage).
*
* @priv: Pointer to the epoll file to be currently checked.
- * @cookie: Original cookie for this call. This is the top-of-the-chain epoll
- * data structure pointer.
- * @call_nests: Current dept of the @ep_call_nested() call stack.
+ * @depth: Current depth of the path being checked.
*
* Returns: Returns zero if adding the epoll @file inside current epoll
* structure @ep does not violate the constraints, or -1 otherwise.
*/
-static int ep_loop_check_proc(void *priv, void *cookie, int depth)
+static int ep_loop_check_proc(struct eventpoll *ep, int depth)
{
int error = 0;
- struct file *file = priv;
- struct eventpoll *ep = file->private_data;
- struct eventpoll *ep_tovisit;
struct rb_node *rbp;
struct epitem *epi;

@@ -1866,15 +1861,14 @@ static int ep_loop_check_proc(void *priv, void *cookie, int depth)
for (rbp = rb_first_cached(&ep->rbr); rbp; rbp = rb_next(rbp)) {
epi = rb_entry(rbp, struct epitem, rbn);
if (unlikely(is_file_epoll(epi->ffd.file))) {
+ struct eventpoll *ep_tovisit;
ep_tovisit = epi->ffd.file->private_data;
if (ep_tovisit->gen == loop_check_gen)
continue;
- if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS) {
+ if (ep_tovisit == inserting_into || depth > EP_MAX_NESTS)
error = -1;
- } else {
- error = ep_loop_check_proc(epi->ffd.file, ep_tovisit,
- depth + 1);
- }
+ else
+ error = ep_loop_check_proc(ep_tovisit, depth + 1);
if (error != 0)
break;
} else {
@@ -1899,20 +1893,20 @@ static int ep_loop_check_proc(void *priv, void *cookie, int depth)
}

/**
- * ep_loop_check - Performs a check to verify that adding an epoll file (@file)
- * another epoll file (represented by @ep) does not create
+ * ep_loop_check - Performs a check to verify that adding an epoll file (@to)
+ * into another epoll file (represented by @from) does not create
* closed loops or too deep chains.
*
- * @ep: Pointer to the epoll private data structure.
- * @file: Pointer to the epoll file to be checked.
+ * @from: Pointer to the epoll we are inserting into.
+ * @to: Pointer to the epoll to be inserted.
*
- * Returns: Returns zero if adding the epoll @file inside current epoll
- * structure @ep does not violate the constraints, or -1 otherwise.
+ * Returns: Returns zero if adding the epoll @to inside the epoll @from
+ * does not violate the constraints, or -1 otherwise.
*/
-static int ep_loop_check(struct eventpoll *ep, struct file *file)
+static int ep_loop_check(struct eventpoll *ep, struct eventpoll *to)
{
inserting_into = ep;
- return ep_loop_check_proc(file, ep, 0);
+ return ep_loop_check_proc(to, 0);
}

static void clear_tfile_check_list(void)
@@ -2086,8 +2080,9 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
loop_check_gen++;
full_check = 1;
if (is_file_epoll(tf.file)) {
+ tep = tf.file->private_data;
error = -ELOOP;
- if (ep_loop_check(ep, tf.file) != 0)
+ if (ep_loop_check(ep, tep) != 0)
goto error_tgt_fput;
} else {
get_file(tf.file);
@@ -2098,7 +2093,6 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
if (error)
goto error_tgt_fput;
if (is_file_epoll(tf.file)) {
- tep = tf.file->private_data;
error = epoll_mutex_lock(&tep->mtx, 1, nonblock);
if (error) {
mutex_unlock(&ep->mtx);
--
2.11.0