[RFC net-next io_uring 09/11] io_uring/notif: add helper for flushing refs

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

Add a helper for dropping notification references during flush. It's a
preparation patch, currently it's only one master ref, but we're going
to add ref caching.

Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
 io_uring/notif.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/io_uring/notif.c b/io_uring/notif.c
index a2ba1e35a59f..5661681b3b44 100644
--- a/io_uring/notif.c
+++ b/io_uring/notif.c
@@ -73,6 +73,13 @@ struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx,
        return notif;
 }
 
+static inline bool io_notif_drop_refs(struct io_notif_data *nd)
+{
+       int refs = 1;
+
+       return refcount_sub_and_test(refs, &nd->uarg.refcnt);
+}
+
 void io_notif_slot_flush(struct io_notif_slot *slot)
        __must_hold(&ctx->uring_lock)
 {
@@ -81,8 +88,7 @@ void io_notif_slot_flush(struct io_notif_slot *slot)
 
        slot->notif = NULL;
 
-       /* drop slot's master ref */
-       if (refcount_dec_and_test(&nd->uarg.refcnt))
+       if (io_notif_drop_refs(nd))
                io_notif_complete(notif);
 }
 
@@ -97,13 +103,11 @@ __cold int io_notif_unregister(struct io_ring_ctx *ctx)
        for (i = 0; i < ctx->nr_notif_slots; i++) {
                struct io_notif_slot *slot = &ctx->notif_slots[i];
                struct io_kiocb *notif = slot->notif;
-               struct io_notif_data *nd;
 
                if (!notif)
                        continue;
-               nd = io_kiocb_to_cmd(notif);
                slot->notif = NULL;
-               if (!refcount_dec_and_test(&nd->uarg.refcnt))
+               if (!io_notif_drop_refs(io_kiocb_to_cmd(notif)))
                        continue;
                notif->io_task_work.func = __io_notif_complete_tw;
                io_req_task_work_add(notif);
-- 
2.37.0