13  *  - object w/ a bit
14  *  - free list
18  *  - explicit stack instead of recursion
19  *  - tail recurse on first born instead of immediate push/pop
20  *  - we gather the stuff that should not be killed into tree
25  *  - don't just push entire root set; process in place
37  *		of foo to bar and vice versa. Current code chokes on that.
43  *		upon the beginning and unmark non-junk ones.
61  *		parents (->gc_tree).
63  *		Damn. Added missing check for ->dead in listen queues scanning.
104 	if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {  in unix_get_socket()
106 		struct sock *s = sock->sk;  in unix_get_socket()
109 		if (s && sock->ops && sock->ops->family == PF_UNIX)  in unix_get_socket()
128 		if (atomic_long_inc_return(&u->inflight) == 1) {  in unix_inflight()
129 			BUG_ON(!list_empty(&u->link));  in unix_inflight()
130 			list_add_tail(&u->link, &gc_inflight_list);  in unix_inflight()
132 			BUG_ON(list_empty(&u->link));  in unix_inflight()
136 	user->unix_inflight++;  in unix_inflight()
149 		BUG_ON(!atomic_long_read(&u->inflight));  in unix_notinflight()
150 		BUG_ON(list_empty(&u->link));  in unix_notinflight()
152 		if (atomic_long_dec_and_test(&u->inflight))  in unix_notinflight()
153 			list_del_init(&u->link);  in unix_notinflight()
154 		unix_tot_inflight--;  in unix_notinflight()
156 	user->unix_inflight--;  in unix_notinflight()
166 	spin_lock(&x->sk_receive_queue.lock);  in scan_inflight()
167 	skb_queue_walk_safe(&x->sk_receive_queue, skb, next) {  in scan_inflight()
172 			int nfd = UNIXCB(skb).fp->count;  in scan_inflight()
173 			struct file **fp = UNIXCB(skb).fp->fp;  in scan_inflight()
175 			while (nfd--) {  in scan_inflight()
182 					/* Ignore non-candidates, they could  in scan_inflight()
186 					if (test_bit(UNIX_GC_CANDIDATE, &u->gc_flags)) {  in scan_inflight()
194 				__skb_unlink(skb, &x->sk_receive_queue);  in scan_inflight()
199 	spin_unlock(&x->sk_receive_queue.lock);  in scan_inflight()
205 	if (x->sk_state != TCP_LISTEN) {  in scan_children()
216 		spin_lock(&x->sk_receive_queue.lock);  in scan_children()
217 		skb_queue_walk_safe(&x->sk_receive_queue, skb, next) {  in scan_children()
218 			u = unix_sk(skb->sk);  in scan_children()
220 			/* An embryo cannot be in-flight, so it's safe  in scan_children()
223 			BUG_ON(!list_empty(&u->link));  in scan_children()
224 			list_add_tail(&u->link, &embryos);  in scan_children()
226 		spin_unlock(&x->sk_receive_queue.lock);  in scan_children()
230 			scan_inflight(&u->sk, func, hitlist);  in scan_children()
231 			list_del_init(&u->link);  in scan_children()
238 	atomic_long_dec(&usk->inflight);  in dec_inflight()
243 	atomic_long_inc(&usk->inflight);  in inc_inflight()
248 	atomic_long_inc(&u->inflight);  in inc_inflight_move_tail()
253 	if (test_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags))  in inc_inflight_move_tail()
254 		list_move_tail(&u->link, &gc_candidates);  in inc_inflight_move_tail()
287 	 * in-flight sockets are considered, and from those only ones  in unix_gc()
298 	 * added to queue, so we must make sure only to touch  in unix_gc()
305 		total_refs = file_count(u->sk.sk_socket->file);  in unix_gc()
306 		inflight_refs = atomic_long_read(&u->inflight);  in unix_gc()
311 			list_move_tail(&u->link, &gc_candidates);  in unix_gc()
312 			__set_bit(UNIX_GC_CANDIDATE, &u->gc_flags);  in unix_gc()
313 			__set_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags);  in unix_gc()
317 	/* Now remove all internal in-flight reference to children of  in unix_gc()
321 		scan_children(&u->sk, dec_inflight, NULL);  in unix_gc()
335 		list_move(&cursor, &u->link);  in unix_gc()
337 		if (atomic_long_read(&u->inflight) > 0) {  in unix_gc()
338 			list_move_tail(&u->link, &not_cycle_list);  in unix_gc()
339 			__clear_bit(UNIX_GC_MAYBE_CYCLE, &u->gc_flags);  in unix_gc()
340 			scan_children(&u->sk, inc_inflight_move_tail, NULL);  in unix_gc()
351 		scan_children(&u->sk, inc_inflight, &hitlist);  in unix_gc()
358 		__clear_bit(UNIX_GC_CANDIDATE, &u->gc_flags);  in unix_gc()
359 		list_move_tail(&u->link, &gc_inflight_list);  in unix_gc()