io_uring/rsrc: remove rsrc_data refs

Instead of waiting for rsrc_data->refs to be downed to zero, check
whether there are rsrc nodes queued for completion, that's easier then
maintaining references.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8e33fd143d83e11af3e386aea28eb6d6c6a1be10.1681395792.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
index 5c96453..1b2a20a 100644 (file)
--- a/include/linux/io_uring_types.h
+++ b/include/linux/io_uring_types.h
@@ -334,6 +334,7 @@ struct io_ring_ctx {
        struct list_head                rsrc_ref_list;
        struct io_alloc_cache           rsrc_node_cache;
        struct wait_queue_head          rsrc_quiesce_wq;
+       unsigned                        rsrc_quiesce;
 
        struct list_head                io_buffers_pages;
 

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 3c1c8c7..3d43df8 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2831,8 +2831,8 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 {
        io_sq_thread_finish(ctx);
        /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
-       io_wait_rsrc_data(ctx->buf_data);
-       io_wait_rsrc_data(ctx->file_data);
+       if (WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)))
+               return;
 
        mutex_lock(&ctx->uring_lock);
        if (ctx->buf_data)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index e634ef3..5415a18 100644 (file)
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -31,11 +31,6 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 #define IORING_MAX_FIXED_FILES (1U << 20)
 #define IORING_MAX_REG_BUFFERS (1U << 14)
 
-static inline bool io_put_rsrc_data_ref(struct io_rsrc_data *rsrc_data)
-{
-       return !--rsrc_data->refs;
-}
-
 int __io_account_mem(struct user_struct *user, unsigned long nr_pages)
 {
        unsigned long page_limit, cur_pages, new_pages;
@@ -158,7 +153,6 @@ static void io_rsrc_put_work_one(struct io_rsrc_data *rsrc_data,
 static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
 {
        struct io_rsrc_data *rsrc_data = ref_node->rsrc_data;
-       struct io_ring_ctx *ctx = rsrc_data->ctx;
        struct io_rsrc_put *prsrc, *tmp;
 
        if (ref_node->inline_items)
@@ -171,14 +165,6 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node)
        }
 
        io_rsrc_node_destroy(rsrc_data->ctx, ref_node);
-       if (io_put_rsrc_data_ref(rsrc_data))
-               wake_up_all(&ctx->rsrc_quiesce_wq);
-}
-
-void io_wait_rsrc_data(struct io_rsrc_data *data)
-{
-       if (data)
-               WARN_ON_ONCE(!io_put_rsrc_data_ref(data));
 }
 
 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
@@ -201,6 +187,8 @@ void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
                list_del(&node->node);
                __io_rsrc_put_work(node);
        }
+       if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce))
+               wake_up_all(&ctx->rsrc_quiesce_wq);
 }
 
 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
@@ -235,7 +223,6 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx,
        if (WARN_ON_ONCE(!backup))
                return;
 
-       data_to_kill->refs++;
        node->rsrc_data = data_to_kill;
        list_add_tail(&node->node, &ctx->rsrc_ref_list);
        /* put master ref */
@@ -269,8 +256,7 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
                return ret;
        io_rsrc_node_switch(ctx, data);
 
-       /* kill initial ref */
-       if (io_put_rsrc_data_ref(data))
+       if (list_empty(&ctx->rsrc_ref_list))
                return 0;
 
        if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
@@ -278,6 +264,7 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
                smp_mb();
        }
 
+       ctx->rsrc_quiesce++;
        data->quiesce = true;
        do {
                prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE);
@@ -286,12 +273,8 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
                ret = io_run_task_work_sig(ctx);
                if (ret < 0) {
                        mutex_lock(&ctx->uring_lock);
-                       if (!data->refs) {
+                       if (list_empty(&ctx->rsrc_ref_list))
                                ret = 0;
-                       } else {
-                               /* restore the master reference */
-                               data->refs++;
-                       }
                        break;
                }
 
@@ -299,10 +282,12 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
                __set_current_state(TASK_RUNNING);
                mutex_lock(&ctx->uring_lock);
                ret = 0;
-       } while (data->refs);
+       } while (!list_empty(&ctx->rsrc_ref_list));
 
        finish_wait(&ctx->rsrc_quiesce_wq, &we);
        data->quiesce = false;
+       ctx->rsrc_quiesce--;
+
        if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
                atomic_set(&ctx->cq_wait_nr, 0);
                smp_mb();
@@ -371,7 +356,6 @@ __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx,
        data->nr = nr;
        data->ctx = ctx;
        data->do_put = do_put;
-       data->refs = 1;
        if (utags) {
                ret = -EFAULT;
                for (i = 0; i < nr; i++) {

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index d93ba4e..5dd2fcb 100644 (file)
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -35,7 +35,6 @@ struct io_rsrc_data {
        u64                             **tags;
        unsigned int                    nr;
        rsrc_put_fn                     *do_put;
-       int                             refs;
        bool                            quiesce;
 };
 
@@ -69,7 +68,6 @@ struct io_mapped_ubuf {
 void io_rsrc_put_tw(struct callback_head *cb);
 void io_rsrc_node_ref_zero(struct io_rsrc_node *node);
 void io_rsrc_put_work(struct work_struct *work);
-void io_wait_rsrc_data(struct io_rsrc_data *data);
 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *ref_node);
 int io_rsrc_node_switch_start(struct io_ring_ctx *ctx);
 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx);