linux-kernel - [PATCH 5.8 16/70] io_uring: Convert advanced XArray uses to the normal API

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Date:   Sat, 31 Oct 2020 12:35:48 +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,
        "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        Jens Axboe <axboe@...nel.dk>
Subject: [PATCH 5.8 16/70] io_uring: Convert advanced XArray uses to the normal API

From: "Matthew Wilcox (Oracle)" <willy@...radead.org>

commit 5e2ed8c4f45093698855b1f45cdf43efbf6dd498 upstream.

There are no bugs here that I've spotted, it's just easier to use the
normal API and there are no performance advantages to using the more
verbose advanced API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/io_uring.c |   14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7958,27 +7958,17 @@ static int io_uring_add_task_file(struct
 static void io_uring_del_task_file(struct file *file)
 {
 	struct io_uring_task *tctx = current->io_uring;
-	XA_STATE(xas, &tctx->xa, (unsigned long) file);
 
 	if (tctx->last == file)
 		tctx->last = NULL;
-
-	xas_lock(&xas);
-	file = xas_store(&xas, NULL);
-	xas_unlock(&xas);
-
+	file = xa_erase(&tctx->xa, (unsigned long)file);
 	if (file)
 		fput(file);
 }
 
 static void __io_uring_attempt_task_drop(struct file *file)
 {
-	XA_STATE(xas, &current->io_uring->xa, (unsigned long) file);
-	struct file *old;
-
-	rcu_read_lock();
-	old = xas_load(&xas);
-	rcu_read_unlock();
+	struct file *old = xa_load(&current->io_uring->xa, (unsigned long)file);
 
 	if (old == file)
 		io_uring_del_task_file(file);