Commit baf186c4 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: index io_uring->xa by ctx not file 



We don't use task file notes anymore, and no need left in indexing
task->io_uring->xa by file, and replace it with ctx. It's better
design-wise, especially since we keep a dangling file, and so have to
keep an eye on not dereferencing it.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent eebd2e37

fs/io_uring.c

+11 −13
Original line number Diff line number Diff line
@@ -809,7 +809,6 @@ struct io_kiocb { 
struct io_tctx_node {

	struct list_head	ctx_node;

	struct task_struct	*task;

	struct file		*file;

	struct io_ring_ctx	*ctx;

};
@@ -8540,7 +8539,7 @@ static bool io_run_ctx_fallback(struct io_ring_ctx *ctx) 
struct io_tctx_exit {

	struct callback_head		task_work;

	struct completion		completion;

	unsigned long			index;

	struct io_ring_ctx		*ctx;

};



static void io_tctx_exit_cb(struct callback_head *cb)
@@ -8554,7 +8553,7 @@ static void io_tctx_exit_cb(struct callback_head *cb) 
	 * 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);

		io_uring_del_task_file((unsigned long)work->ctx);

	complete(&work->completion);

}
@@ -8579,7 +8578,7 @@ static void io_ring_exit_work(struct work_struct *work) 
	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;

		exit.ctx = ctx;

		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);
@@ -8798,7 +8797,7 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx, 
/*

 * Note that this task has used io_uring. We use it for cancelation purposes.

 */

static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)

static int io_uring_add_task_file(struct io_ring_ctx *ctx)

{

	struct io_uring_task *tctx = current->io_uring;

	struct io_tctx_node *node;
@@ -8810,18 +8809,17 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file) 
			return ret;

		tctx = current->io_uring;

	}

	if (tctx->last != file) {

		void *old = xa_load(&tctx->xa, (unsigned long)file);

	if (tctx->last != ctx) {

		void *old = xa_load(&tctx->xa, (unsigned long)ctx);



		if (!old) {

			node = kmalloc(sizeof(*node), GFP_KERNEL);

			if (!node)

				return -ENOMEM;

			node->ctx = ctx;

			node->file = file;

			node->task = current;



			ret = xa_err(xa_store(&tctx->xa, (unsigned long)file,

			ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,

						node, GFP_KERNEL));

			if (ret) {

				kfree(node);
@@ -8832,7 +8830,7 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file) 
			list_add(&node->ctx_node, &ctx->tctx_list);

			mutex_unlock(&ctx->uring_lock);

		}

		tctx->last = file;

		tctx->last = ctx;

	}



	/*
@@ -8867,7 +8865,7 @@ static void io_uring_del_task_file(unsigned long index) 
	list_del(&node->ctx_node);

	mutex_unlock(&node->ctx->uring_lock);



	if (tctx->last == node->file)

	if (tctx->last == node->ctx)

		tctx->last = NULL;

	kfree(node);

}
@@ -9166,7 +9164,7 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, 
		}

		submitted = to_submit;

	} else if (to_submit) {

		ret = io_uring_add_task_file(ctx, f.file);

		ret = io_uring_add_task_file(ctx);

		if (unlikely(ret))

			goto out;

		mutex_lock(&ctx->uring_lock);
@@ -9375,7 +9373,7 @@ static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) 
	if (fd < 0)

		return fd;



	ret = io_uring_add_task_file(ctx, file);

	ret = io_uring_add_task_file(ctx);

	if (ret) {

		put_unused_fd(fd);

		return ret;

include/linux/io_uring.h

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ struct io_uring_task { 
	/* submission side */

	struct xarray		xa;

	struct wait_queue_head	wait;

	struct file		*last;

	void			*last;

	void			*io_wq;

	struct percpu_counter	inflight;

	atomic_t		in_idle;