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From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH v4 2/8] io_uring: introduce ctx to tctx back map
Date: Sat,  6 Mar 2021 11:02:12 +0000	[thread overview]
Message-ID: <27593efc21aadc34312f4900caa8b7b4aa71802e.1615028377.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>

For each pair tcxt-ctx create an object and chain it into ctx, so we
have a way to traverse all tctx that are using current ctx. Preparation
patch, will be used later.

Signed-off-by: Pavel Begunkov <[email protected]>
---
 fs/io_uring.c | 58 ++++++++++++++++++++++++++++++++++++++-------------
 1 file changed, 44 insertions(+), 14 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 4c6a92e5d5a3..f26f8199e4ab 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -454,6 +454,7 @@ struct io_ring_ctx {
 
 	/* Keep this last, we don't need it for the fast path */
 	struct work_struct		exit_work;
+	struct list_head		tctx_list;
 };
 
 /*
@@ -805,6 +806,13 @@ struct io_kiocb {
 	struct io_wq_work		work;
 };
 
+struct io_tctx_node {
+	struct list_head	ctx_node;
+	struct task_struct	*task;
+	struct file		*file;
+	struct io_ring_ctx	*ctx;
+};
+
 struct io_defer_entry {
 	struct list_head	list;
 	struct io_kiocb		*req;
@@ -1144,6 +1152,7 @@ static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
 	INIT_LIST_HEAD(&ctx->rsrc_ref_list);
 	INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
 	init_llist_head(&ctx->rsrc_put_llist);
+	INIT_LIST_HEAD(&ctx->tctx_list);
 	INIT_LIST_HEAD(&ctx->submit_state.comp.free_list);
 	INIT_LIST_HEAD(&ctx->submit_state.comp.locked_free_list);
 	return ctx;
@@ -8743,6 +8752,7 @@ static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
 static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
 {
 	struct io_uring_task *tctx = current->io_uring;
+	struct io_tctx_node *node;
 	int ret;
 
 	if (unlikely(!tctx)) {
@@ -8755,13 +8765,25 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
 		void *old = xa_load(&tctx->xa, (unsigned long)file);
 
 		if (!old) {
+			node = kmalloc(sizeof(*node), GFP_KERNEL);
+			if (!node)
+				return -ENOMEM;
+			node->ctx = ctx;
+			node->file = file;
+			node->task = current;
+
 			get_file(file);
 			ret = xa_err(xa_store(&tctx->xa, (unsigned long)file,
-						file, GFP_KERNEL));
+						node, GFP_KERNEL));
 			if (ret) {
 				fput(file);
+				kfree(node);
 				return ret;
 			}
+
+			mutex_lock(&ctx->uring_lock);
+			list_add(&node->ctx_node, &ctx->tctx_list);
+			mutex_unlock(&ctx->uring_lock);
 		}
 		tctx->last = file;
 	}
@@ -8783,23 +8805,31 @@ static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
 static void io_uring_del_task_file(unsigned long index)
 {
 	struct io_uring_task *tctx = current->io_uring;
-	struct file *file;
+	struct io_tctx_node *node;
 
-	file = xa_erase(&tctx->xa, index);
-	if (!file)
+	node = xa_erase(&tctx->xa, index);
+	if (!node)
 		return;
 
-	if (tctx->last == file)
+	WARN_ON_ONCE(current != node->task);
+	WARN_ON_ONCE(list_empty(&node->ctx_node));
+
+	mutex_lock(&node->ctx->uring_lock);
+	list_del(&node->ctx_node);
+	mutex_unlock(&node->ctx->uring_lock);
+
+	if (tctx->last == node->file)
 		tctx->last = NULL;
-	fput(file);
+	fput(node->file);
+	kfree(node);
 }
 
 static void io_uring_clean_tctx(struct io_uring_task *tctx)
 {
-	struct file *file;
+	struct io_tctx_node *node;
 	unsigned long index;
 
-	xa_for_each(&tctx->xa, index, file)
+	xa_for_each(&tctx->xa, index, node)
 		io_uring_del_task_file(index);
 	if (tctx->io_wq) {
 		io_wq_put_and_exit(tctx->io_wq);
@@ -8810,13 +8840,13 @@ static void io_uring_clean_tctx(struct io_uring_task *tctx)
 void __io_uring_files_cancel(struct files_struct *files)
 {
 	struct io_uring_task *tctx = current->io_uring;
-	struct file *file;
+	struct io_tctx_node *node;
 	unsigned long index;
 
 	/* make sure overflow events are dropped */
 	atomic_inc(&tctx->in_idle);
-	xa_for_each(&tctx->xa, index, file)
-		io_uring_cancel_task_requests(file->private_data, files);
+	xa_for_each(&tctx->xa, index, node)
+		io_uring_cancel_task_requests(node->ctx, files);
 	atomic_dec(&tctx->in_idle);
 
 	if (files)
@@ -8879,11 +8909,11 @@ void __io_uring_task_cancel(void)
 	atomic_inc(&tctx->in_idle);
 
 	if (tctx->sqpoll) {
-		struct file *file;
+		struct io_tctx_node *node;
 		unsigned long index;
 
-		xa_for_each(&tctx->xa, index, file)
-			io_uring_cancel_sqpoll(file->private_data);
+		xa_for_each(&tctx->xa, index, node)
+			io_uring_cancel_sqpoll(node->ctx);
 	}
 
 	do {
-- 
2.24.0


  parent reply	other threads:[~2021-03-06 11:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-06 11:02 [PATCH v4 5.12 0/8] remove task file notes Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 1/8] io_uring: make del_task_file more forgiving Pavel Begunkov
2021-03-06 11:02 ` Pavel Begunkov [this message]
2021-03-06 11:02 ` [PATCH v4 3/8] io_uring: do ctx initiated file note removal Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 4/8] io_uring: don't take task ring-file notes Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 5/8] io_uring: index io_uring->xa by ctx not file Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 6/8] io_uring: warn when ring exit takes too long Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 7/8] io_uring: cancel reqs of all iowq's on ring exit Pavel Begunkov
2021-03-06 11:02 ` [PATCH v4 8/8] io-wq: warn on creating manager awhile exiting Pavel Begunkov
2021-03-08 21:05 ` [PATCH v4 5.12 0/8] remove task file notes Jens Axboe

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