diff options
| -rw-r--r-- | fs/eventpoll.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index df364a8783b5..0e65c7431dfc 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -433,7 +433,11 @@ struct ep_ctl_ctx { /* * Singly-linked list of epitems_head objects collected during * ep_loop_check_proc(), then walked by reverse_path_check(). - * NULL means empty. + * Terminated by EP_UNACTIVE_PTR, not NULL: epitems_head->next + * doubles as a membership flag (a NULL ->next means "not on this + * list", see ep_remove_file()), so the list uses a non-NULL + * sentinel to keep the tail head distinguishable from an unlisted + * one. */ struct epitems_head *tfile_check_list; @@ -1704,7 +1708,7 @@ static int reverse_path_check(struct ep_ctl_ctx *ctx) { struct epitems_head *p; - for (p = ctx->tfile_check_list; p; p = p->next) { + for (p = ctx->tfile_check_list; p != EP_UNACTIVE_PTR; p = p->next) { int error; path_count_init(ctx); rcu_read_lock(); @@ -2458,7 +2462,7 @@ static int ep_loop_check(struct ep_ctl_ctx *ctx, struct eventpoll *ep, static void clear_tfile_check_list(struct ep_ctl_ctx *ctx) { rcu_read_lock(); - while (ctx->tfile_check_list) { + while (ctx->tfile_check_list != EP_UNACTIVE_PTR) { struct epitems_head *head = ctx->tfile_check_list; ctx->tfile_check_list = head->next; unlist_file(head); @@ -2621,7 +2625,9 @@ int do_epoll_ctl_file(struct file *f, int op, struct epoll_key *tf, int full_check; struct eventpoll *ep; struct epitem *epi; - struct ep_ctl_ctx ctx = { }; + struct ep_ctl_ctx ctx = { + .tfile_check_list = EP_UNACTIVE_PTR, + }; /* The target file descriptor must support poll */ if (!file_can_poll(tf->file)) |