Commit d56d938b authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: do ctx initiated file note removal 



Another preparation patch. When full quiesce is done on ctx exit, use
task_work infra to remove corresponding to the ctx io_uring->xa entries.
For that we use the back tctx map. Also use ->in_idle to prevent
removing it while we traversing ->xa on cancellation, just ignore it.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 13bf43f5

fs/io_uring.c

+46 −2
Original line number Diff line number Diff line
@@ -987,6 +987,7 @@ static const struct io_op_def io_op_defs[] = { 
	[IORING_OP_UNLINKAT] = {},

};



static void io_uring_del_task_file(unsigned long index);

static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx,

					 struct task_struct *task,

					 struct files_struct *files);
@@ -8536,10 +8537,33 @@ static bool io_run_ctx_fallback(struct io_ring_ctx *ctx) 
	return executed;

}



struct io_tctx_exit {

	struct callback_head		task_work;

	struct completion		completion;

	unsigned long			index;

};



static void io_tctx_exit_cb(struct callback_head *cb)

{

	struct io_uring_task *tctx = current->io_uring;

	struct io_tctx_exit *work;



	work = container_of(cb, struct io_tctx_exit, task_work);

	/*

	 * When @in_idle, we're in cancellation and it's racy to remove the

	 * node. It'll be removed by the end of cancellation, just ignore it.

	 */

	if (!atomic_read(&tctx->in_idle))

		io_uring_del_task_file(work->index);

	complete(&work->completion);

}



static void io_ring_exit_work(struct work_struct *work)

{

	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,

					       exit_work);

	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);

	struct io_tctx_exit exit;

	struct io_tctx_node *node;

	int ret;



	/*

	 * If we're doing polled IO and end up having requests being
@@ -8550,6 +8574,26 @@ static void io_ring_exit_work(struct work_struct *work) 
	do {

		io_uring_try_cancel_requests(ctx, NULL, NULL);

	} while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));



	mutex_lock(&ctx->uring_lock);

	while (!list_empty(&ctx->tctx_list)) {

		node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,

					ctx_node);

		exit.index = (unsigned long)node->file;

		init_completion(&exit.completion);

		init_task_work(&exit.task_work, io_tctx_exit_cb);

		ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);

		if (WARN_ON_ONCE(ret))

			continue;

		wake_up_process(node->task);



		mutex_unlock(&ctx->uring_lock);

		wait_for_completion(&exit.completion);

		cond_resched();

		mutex_lock(&ctx->uring_lock);

	}

	mutex_unlock(&ctx->uring_lock);



	io_ring_ctx_free(ctx);

}