author: Siddh Raman Pant <code@siddh.me> 2023-06-05 20:06:16 +0530
committer: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 2023-07-19 16:36:53 +0200
commit: bec85c4df15d29664245f7b7e9cd7dc926d6e699
parent: 4514847aee18d9391a0cf3aad75d3567c72795a4
Commit Summary:
Diffstat:
2 files changed, 7 insertions, 8 deletions
diff --git a/include/linux/watch_queue.h b/include/linux/watch_queue.h
index fc6bba20273b..45cd42f55d49 100644
--- a/include/linux/watch_queue.h
+++ b/include/linux/watch_queue.h
@@ -38,7 +38,7 @@ struct watch_filter {
struct watch_queue {
struct rcu_head rcu;
struct watch_filter __rcu *filter;
- struct pipe_inode_info *pipe; /* The pipe we're using as a buffer */
+ struct pipe_inode_info *pipe; /* Pipe we use as a buffer, NULL if queue closed */
struct hlist_head watches; /* Contributory watches */
struct page **notes; /* Preallocated notifications */
unsigned long *notes_bitmap; /* Allocation bitmap for notes */
@@ -46,7 +46,6 @@ struct watch_queue {
spinlock_t lock;
unsigned int nr_notes; /* Number of notes */
unsigned int nr_pages; /* Number of pages in notes[] */
- bool defunct; /* T when queues closed */
};
/*
diff --git a/kernel/watch_queue.c b/kernel/watch_queue.c
index e91cb4c2833f..d0b6b390ee42 100644
--- a/kernel/watch_queue.c
+++ b/kernel/watch_queue.c
@@ -42,7 +42,7 @@ MODULE_AUTHOR("Red Hat, Inc.");
static inline bool lock_wqueue(struct watch_queue *wqueue)
{
spin_lock_bh(&wqueue->lock);
- if (unlikely(wqueue->defunct)) {
+ if (unlikely(!wqueue->pipe)) {
spin_unlock_bh(&wqueue->lock);
return false;
}
@@ -104,9 +104,6 @@ static bool post_one_notification(struct watch_queue *wqueue,
unsigned int head, tail, mask, note, offset, len;
bool done = false;
- if (!pipe)
- return false;
-
spin_lock_irq(&pipe->rd_wait.lock);
mask = pipe->ring_size - 1;
@@ -603,8 +600,11 @@ void watch_queue_clear(struct watch_queue *wqueue)
rcu_read_lock();
spin_lock_bh(&wqueue->lock);
- /* Prevent new notifications from being stored. */
- wqueue->defunct = true;
+ /*
+ * This pipe can be freed by callers like free_pipe_info().
+ * Removing this reference also prevents new notifications.
+ */
+ wqueue->pipe = NULL;
while (!hlist_empty(&wqueue->watches)) {
watch = hlist_entry(wqueue->watches.first, struct watch, queue_node);