[RFC PATCH 24/27] convert ->f_ep_links/->fllink to hlist

Al Viro
2020-10-04T02:40:35Z

we don't care about the order of elements there

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
fs/eventpoll.c | 18 +++++++++---------
include/linux/eventpoll.h | 4 ++--
include/linux/fs.h | 2 +-
3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 66da645d5eb4..78b8769b72dc 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -160,7 +160,7 @@ struct epitem {
struct eventpoll *ep;

/* List header used to link this item to the "struct file" items list */
- struct list_head fllink;
+ struct hlist_node fllink;

/* wakeup_source used when EPOLLWAKEUP is set */
struct wakeup_source __rcu *ws;
@@ -642,7 +642,7 @@ static int ep_remove(struct eventpoll *ep, struct epitem *epi)

/* Remove the current item from the list of epoll hooks */
spin_lock(&file->f_lock);
- list_del_rcu(&epi->fllink);
+ hlist_del_rcu(&epi->fllink);
spin_unlock(&file->f_lock);

rb_erase_cached(&epi->rbn, &ep->rbr);
@@ -835,7 +835,8 @@ static const struct file_operations eventpoll_fops = {
void eventpoll_release_file(struct file *file)
{
struct eventpoll *ep;
- struct epitem *epi, *next;
+ struct epitem *epi;
+ struct hlist_node *next;

/*
* We don't want to get "file->f_lock" because it is not
@@ -851,7 +852,7 @@ void eventpoll_release_file(struct file *file)
* Besides, ep_remove() acquires the lock, so we can't hold it here.
*/
mutex_lock(&epmutex);
- list_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) {
+ hlist_for_each_entry_safe(epi, next, &file->f_ep_links, fllink) {
ep = epi->ep;
mutex_lock_nested(&ep->mtx, 0);
ep_remove(ep, epi);
@@ -1257,11 +1258,11 @@ static int reverse_path_check_proc(struct file *file, int depth)

/* 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) {
+ hlist_for_each_entry_rcu(epi, &file->f_ep_links, fllink) {
struct file *recepient = epi->ep->file;
if (WARN_ON(!is_file_epoll(recepient)))
continue;
- if (list_empty(&recepient->f_ep_links))
+ if (hlist_empty(&recepient->f_ep_links))
error = path_count_inc(depth);
else
error = reverse_path_check_proc(recepient, depth + 1);
@@ -1361,7 +1362,6 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event,

/* Item initialization follow here ... */
INIT_LIST_HEAD(&epi->rdllink);
- INIT_LIST_HEAD(&epi->fllink);
epi->ep = ep;
ep_set_ffd(&epi->ffd, tfile, fd);
epi->event = *event;
@@ -1373,7 +1373,7 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event,
mutex_lock(&tep->mtx);
/* Add the current item to the list of active epoll hook for this file */
spin_lock(&tfile->f_lock);
- list_add_tail_rcu(&epi->fllink, &tfile->f_ep_links);
+ hlist_add_head_rcu(&epi->fllink, &tfile->f_ep_links);
spin_unlock(&tfile->f_lock);

/*
@@ -1999,7 +1999,7 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
if (error)
goto error_tgt_fput;
if (op == EPOLL_CTL_ADD) {
- if (!list_empty(&f.file->f_ep_links) ||
+ if (!hlist_empty(&f.file->f_ep_links) ||
ep->gen == loop_check_gen ||
is_file_epoll(tf.file)) {
mutex_unlock(&ep->mtx);
diff --git a/include/linux/eventpoll.h b/include/linux/eventpoll.h
index 8f000fada5a4..4e215ccfa792 100644
--- a/include/linux/eventpoll.h
+++ b/include/linux/eventpoll.h
@@ -25,7 +25,7 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long t
/* Used to initialize the epoll bits inside the "struct file" */
static inline void eventpoll_init_file(struct file *file)
{
- INIT_LIST_HEAD(&file->f_ep_links);
+ INIT_HLIST_HEAD(&file->f_ep_links);
INIT_LIST_HEAD(&file->f_tfile_llink);
}

@@ -50,7 +50,7 @@ static inline void eventpoll_release(struct file *file)
* because the file in on the way to be removed and nobody ( but
* eventpoll ) has still a reference to this file.
*/
- if (likely(list_empty(&file->f_ep_links)))
+ if (likely(hlist_empty(&file->f_ep_links)))
return;

/*
diff --git a/include/linux/fs.h b/include/linux/fs.h
index e019ea2f1347..9dc4c09f1d13 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -951,7 +951,7 @@ struct file {

#ifdef CONFIG_EPOLL
/* Used by fs/eventpoll.c to link all the hooks to this file */
- struct list_head f_ep_links;
+ struct hlist_head f_ep_links;
struct list_head f_tfile_llink;
#endif /* #ifdef CONFIG_EPOLL */
struct address_space *f_mapping;
--
2.11.0