io_uring/zcrx: count zcrx users

zcrx tries to detach ifq / terminate page pools when the io_uring ctx
owning it is being destroyed. There will be multiple io_uring instances
attached to it in the future, so add a separate counter to track the
users. Note, refs can't be reused for this purpose as it only used to
prevent zcrx and rings destruction, and also used by page pools to keep
it alive.

Signed-off-by: David Wei <dw@davidwei.uk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
index 08c103a..2335f14 100644 (file)
--- a/io_uring/zcrx.c
+++ b/io_uring/zcrx.c
@@ -482,6 +482,7 @@ static struct io_zcrx_ifq *io_zcrx_ifq_alloc(struct io_ring_ctx *ctx)
        spin_lock_init(&ifq->rq_lock);
        mutex_init(&ifq->pp_lock);
        refcount_set(&ifq->refs, 1);
+       refcount_set(&ifq->user_refs, 1);
        return ifq;
 }
 
@@ -742,8 +743,10 @@ void io_unregister_zcrx_ifqs(struct io_ring_ctx *ctx)
                if (!ifq)
                        break;
 
-               io_close_queue(ifq);
-               io_zcrx_scrub(ifq);
+               if (refcount_dec_and_test(&ifq->user_refs)) {
+                       io_close_queue(ifq);
+                       io_zcrx_scrub(ifq);
+               }
                io_put_zcrx_ifq(ifq);
        }
 

diff --git a/io_uring/zcrx.h b/io_uring/zcrx.h
index f29edc2..32ab95b 100644 (file)
--- a/io_uring/zcrx.h
+++ b/io_uring/zcrx.h
@@ -55,6 +55,8 @@ struct io_zcrx_ifq {
        struct net_device               *netdev;
        netdevice_tracker               netdev_tracker;
        refcount_t                      refs;
+       /* counts userspace facing users like io_uring */
+       refcount_t                      user_refs;
 
        /*
         * Page pool and net configuration lock, can be taken deeper in the