[PATCH v2 7/8] io_uring: count allocated requests

[Pavel Begunkov <asml.silence@gmail.com>]

Keep track of the number requests a ring currently has allocated (and
not freed), it'll be needed in the next patch.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 include/linux/io_uring_types.h | 1 +
 io_uring/io_uring.c            | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 7e23e993280e..73b289b48280 100644
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -435,6 +435,7 @@ struct io_ring_ctx {
 
 	/* protected by ->completion_lock */
 	unsigned			evfd_last_cq_tail;
+	unsigned			nr_req_allocated;
 
 	/*
 	 * Protection for resize vs mmap races - both the mmap and resize
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 9619c46bd25e..14188f49a4ce 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -954,6 +954,8 @@ __cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
 	}
 
 	percpu_ref_get_many(&ctx->refs, ret);
+	ctx->nr_req_allocated += ret;
+
 	while (ret--) {
 		struct io_kiocb *req = reqs[ret];
 
@@ -2691,8 +2693,10 @@ static void io_req_caches_free(struct io_ring_ctx *ctx)
 		kmem_cache_free(req_cachep, req);
 		nr++;
 	}
-	if (nr)
+	if (nr) {
+		ctx->nr_req_allocated -= nr;
 		percpu_ref_put_many(&ctx->refs, nr);
+	}
 	mutex_unlock(&ctx->uring_lock);
 }
 
@@ -2729,6 +2733,9 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 	percpu_ref_exit(&ctx->refs);
 	free_uid(ctx->user);
 	io_req_caches_free(ctx);
+
+	WARN_ON_ONCE(ctx->nr_req_allocated);
+
 	if (ctx->hash_map)
 		io_wq_put_hash(ctx->hash_map);
 	io_napi_free(ctx);
-- 
2.49.0