af_unix: Remove io_uring code for GC.

commit 11498715f266a3fb4caabba9dd575636cbcaa8f1 upstream.

Since commit 705318a99a13 ("io_uring/af_unix: disable sending
io_uring over sockets"), io_uring's unix socket cannot be passed
via SCM_RIGHTS, so it does not contribute to cyclic reference and
no longer be candidate for garbage collection.

Also, commit 6e5e6d274956 ("io_uring: drop any code related to
SCM_RIGHTS") cleaned up SCM_RIGHTS code in io_uring.

Let's do it in AF_UNIX as well by reverting commit 0091bfc81741
("io_uring/af_unix: defer registered files gc to io_uring release")
and commit 10369080454d ("net: reclaim skb->scm_io_uring bit").

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20240129190435.57228-3-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Lee Jones <lee@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/unix/garbage.c b/net/unix/garbage.c
index 7eeaac165e858272fddc601fe56c80fca243d3e8..c04f82489abb97d76c5a94bd87434566831b43e2 100644 (file)
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -184,12 +184,10 @@ static bool gc_in_progress;
 
 static void __unix_gc(struct work_struct *work)
 {
-       struct sk_buff *next_skb, *skb;
-       struct unix_sock *u;
-       struct unix_sock *next;
        struct sk_buff_head hitlist;
-       struct list_head cursor;
+       struct unix_sock *u, *next;
        LIST_HEAD(not_cycle_list);
+       struct list_head cursor;
 
        spin_lock(&unix_gc_lock);
 
@@ -293,30 +291,11 @@ static void __unix_gc(struct work_struct *work)
 
        spin_unlock(&unix_gc_lock);
 
-       /* We need io_uring to clean its registered files, ignore all io_uring
-        * originated skbs. It's fine as io_uring doesn't keep references to
-        * other io_uring instances and so killing all other files in the cycle
-        * will put all io_uring references forcing it to go through normal
-        * release.path eventually putting registered files.
-        */
-       skb_queue_walk_safe(&hitlist, skb, next_skb) {
-               if (skb->scm_io_uring) {
-                       __skb_unlink(skb, &hitlist);
-                       skb_queue_tail(&skb->sk->sk_receive_queue, skb);
-               }
-       }
-
        /* Here we are. Hitlist is filled. Die. */
        __skb_queue_purge(&hitlist);
 
        spin_lock(&unix_gc_lock);
 
-       /* There could be io_uring registered files, just push them back to
-        * the inflight list
-        */
-       list_for_each_entry_safe(u, next, &gc_candidates, link)
-               list_move_tail(&u->link, &gc_inflight_list);
-
        /* All candidates should have been detached by now. */
        WARN_ON_ONCE(!list_empty(&gc_candidates));