linux-kernel - [PATCH 5.9 03/74] io_uring: allow timeout/poll/files killing to take task into account

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Date:   Sat, 31 Oct 2020 12:35:45 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Pavel Begunkov <asml.silence@...il.com>,
        Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 5.9 03/74] io_uring: allow timeout/poll/files killing to take task into account

From: Jens Axboe <axboe@...nel.dk>

commit 07d3ca52b0056f25eef61b1c896d089f8d365468 upstream.

We currently cancel these when the ring exits, and we cancel all of
them. This is in preparation for killing only the ones associated
with a given task.

Reviewed-by: Pavel Begunkov <asml.silence@...il.com>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/io_uring.c |   33 ++++++++++++++++++++++++---------
 1 file changed, 24 insertions(+), 9 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1226,13 +1226,26 @@ static void io_kill_timeout(struct io_ki
 	}
 }
 
-static void io_kill_timeouts(struct io_ring_ctx *ctx)
+static bool io_task_match(struct io_kiocb *req, struct task_struct *tsk)
+{
+	struct io_ring_ctx *ctx = req->ctx;
+
+	if (!tsk || req->task == tsk)
+		return true;
+	if ((ctx->flags & IORING_SETUP_SQPOLL) && req->task == ctx->sqo_thread)
+		return true;
+	return false;
+}
+
+static void io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk)
 {
 	struct io_kiocb *req, *tmp;
 
 	spin_lock_irq(&ctx->completion_lock);
-	list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list)
-		io_kill_timeout(req);
+	list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
+		if (io_task_match(req, tsk))
+			io_kill_timeout(req);
+	}
 	spin_unlock_irq(&ctx->completion_lock);
 }
 
@@ -5017,7 +5030,7 @@ static bool io_poll_remove_one(struct io
 	return do_complete;
 }
 
-static void io_poll_remove_all(struct io_ring_ctx *ctx)
+static void io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk)
 {
 	struct hlist_node *tmp;
 	struct io_kiocb *req;
@@ -5028,8 +5041,10 @@ static void io_poll_remove_all(struct io
 		struct hlist_head *list;
 
 		list = &ctx->cancel_hash[i];
-		hlist_for_each_entry_safe(req, tmp, list, hash_node)
-			posted += io_poll_remove_one(req);
+		hlist_for_each_entry_safe(req, tmp, list, hash_node) {
+			if (io_task_match(req, tsk))
+				posted += io_poll_remove_one(req);
+		}
 	}
 	spin_unlock_irq(&ctx->completion_lock);
 
@@ -7989,8 +8004,8 @@ static void io_ring_ctx_wait_and_kill(st
 	percpu_ref_kill(&ctx->refs);
 	mutex_unlock(&ctx->uring_lock);
 
-	io_kill_timeouts(ctx);
-	io_poll_remove_all(ctx);
+	io_kill_timeouts(ctx, NULL);
+	io_poll_remove_all(ctx, NULL);
 
 	if (ctx->io_wq)
 		io_wq_cancel_all(ctx->io_wq);
@@ -8221,7 +8236,7 @@ static bool io_cancel_task_cb(struct io_
 	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
 	struct task_struct *task = data;
 
-	return req->task == task;
+	return io_task_match(req, task);
 }
 
 static int io_uring_flush(struct file *file, void *data)