linux-kernel - [PATCH] usb: gadget: ffs: ffs_aio_cancel(): Save/restore IRQ flags

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Date:   Wed, 6 Nov 2019 14:02:19 +0200
From:   Alexandru Ardelean <alexandru.ardelean@...log.com>
To:     <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <balbi@...nel.org>, <gregkh@...uxfoundation.org>,
        <mina86@...a86.com>, Lars-Peter Clausen <lars@...afoo.de>,
        Alexandru Ardelean <alexandru.ardelean@...log.com>
Subject: [PATCH] usb: gadget: ffs: ffs_aio_cancel(): Save/restore IRQ flags

From: Lars-Peter Clausen <lars@...afoo.de>

ffs_aio_cancel() can be called from both interrupt and thread context. Make
sure that the current IRQ state is saved and restored by using
spin_{un,}lock_irq{save,restore}().

Otherwise undefined behavior might occur.

Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@...log.com>
---
 drivers/usb/gadget/function/f_fs.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index 59d9d512dcda..ed3bcbb84b95 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -1160,18 +1160,19 @@ static int ffs_aio_cancel(struct kiocb *kiocb)
 {
 	struct ffs_io_data *io_data = kiocb->private;
 	struct ffs_epfile *epfile = kiocb->ki_filp->private_data;
+	unsigned long flags;
 	int value;
 
 	ENTER();
 
-	spin_lock_irq(&epfile->ffs->eps_lock);
+	spin_lock_irqsave(&epfile->ffs->eps_lock, flags);
 
 	if (likely(io_data && io_data->ep && io_data->req))
 		value = usb_ep_dequeue(io_data->ep, io_data->req);
 	else
 		value = -EINVAL;
 
-	spin_unlock_irq(&epfile->ffs->eps_lock);
+	spin_unlock_irqrestore(&epfile->ffs->eps_lock, flags);
 
 	return value;
 }
-- 
2.20.1