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* [PATCH 1/3] usb: raw-gadget: properly handle interrupted requests
@ 2023-10-26 14:23 andrey.konovalov
  2023-10-26 14:24 ` [PATCH 2/3] usb: raw-gadget: don't disable device if usb_ep_queue fails andrey.konovalov
  2023-10-26 14:24 ` [PATCH 3/3] usb: raw-gadget: report suspend, resume, reset, and disconnect events andrey.konovalov
  0 siblings, 2 replies; 4+ messages in thread
From: andrey.konovalov @ 2023-10-26 14:23 UTC (permalink / raw)
  To: Greg Kroah-Hartman, Alan Stern
  Cc: Andrey Konovalov, Felipe Balbi, linux-usb, linux-kernel

From: Andrey Konovalov <andreyknvl@gmail.com>

Currently, if a USB request that was queued by Raw Gadget is interrupted
(via a signal), wait_for_completion_interruptible returns -ERESTARTSYS.
Raw Gadget then attempts to propagate this value to userspace as a return
value from its ioctls. However, when -ERESTARTSYS is returned by a syscall
handler, the kernel internally restarts the syscall.

This doesn't allow userspace applications to interrupt requests queued by
Raw Gadget (which is required when the emulated device is asked to switch
altsettings). It also violates the implied interface of Raw Gadget that a
single ioctl must only queue a single USB request.

Instead, make Raw Gadget do what GadgetFS does: check whether the request
was interrupted (dequeued with status == -ECONNRESET) and report -EINTR to
userspace.

Fixes: f2c2e717642c ("usb: gadget: add raw-gadget interface")
Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
---
 drivers/usb/gadget/legacy/raw_gadget.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c
index b9ecc55a2ce2..ce9e87f84911 100644
--- a/drivers/usb/gadget/legacy/raw_gadget.c
+++ b/drivers/usb/gadget/legacy/raw_gadget.c
@@ -674,12 +674,12 @@ static int raw_process_ep0_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
 	if (WARN_ON(in && dev->ep0_out_pending)) {
 		ret = -ENODEV;
 		dev->state = STATE_DEV_FAILED;
-		goto out_done;
+		goto out_unlock;
 	}
 	if (WARN_ON(!in && dev->ep0_in_pending)) {
 		ret = -ENODEV;
 		dev->state = STATE_DEV_FAILED;
-		goto out_done;
+		goto out_unlock;
 	}
 
 	dev->req->buf = data;
@@ -694,7 +694,7 @@ static int raw_process_ep0_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
 				"fail, usb_ep_queue returned %d\n", ret);
 		spin_lock_irqsave(&dev->lock, flags);
 		dev->state = STATE_DEV_FAILED;
-		goto out_done;
+		goto out_queue_failed;
 	}
 
 	ret = wait_for_completion_interruptible(&dev->ep0_done);
@@ -703,13 +703,16 @@ static int raw_process_ep0_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
 		usb_ep_dequeue(dev->gadget->ep0, dev->req);
 		wait_for_completion(&dev->ep0_done);
 		spin_lock_irqsave(&dev->lock, flags);
-		goto out_done;
+		if (dev->ep0_status == -ECONNRESET)
+			dev->ep0_status = -EINTR;
+		goto out_interrupted;
 	}
 
 	spin_lock_irqsave(&dev->lock, flags);
-	ret = dev->ep0_status;
 
-out_done:
+out_interrupted:
+	ret = dev->ep0_status;
+out_queue_failed:
 	dev->ep0_urb_queued = false;
 out_unlock:
 	spin_unlock_irqrestore(&dev->lock, flags);
@@ -1078,7 +1081,7 @@ static int raw_process_ep_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
 				"fail, usb_ep_queue returned %d\n", ret);
 		spin_lock_irqsave(&dev->lock, flags);
 		dev->state = STATE_DEV_FAILED;
-		goto out_done;
+		goto out_queue_failed;
 	}
 
 	ret = wait_for_completion_interruptible(&done);
@@ -1087,13 +1090,16 @@ static int raw_process_ep_io(struct raw_dev *dev, struct usb_raw_ep_io *io,
 		usb_ep_dequeue(ep->ep, ep->req);
 		wait_for_completion(&done);
 		spin_lock_irqsave(&dev->lock, flags);
-		goto out_done;
+		if (ep->status == -ECONNRESET)
+			ep->status = -EINTR;
+		goto out_interrupted;
 	}
 
 	spin_lock_irqsave(&dev->lock, flags);
-	ret = ep->status;
 
-out_done:
+out_interrupted:
+	ret = ep->status;
+out_queue_failed:
 	ep->urb_queued = false;
 out_unlock:
 	spin_unlock_irqrestore(&dev->lock, flags);
-- 
2.25.1


^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-10-26 16:36 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-10-26 14:23 [PATCH 1/3] usb: raw-gadget: properly handle interrupted requests andrey.konovalov
2023-10-26 14:24 ` [PATCH 2/3] usb: raw-gadget: don't disable device if usb_ep_queue fails andrey.konovalov
2023-10-26 14:24 ` [PATCH 3/3] usb: raw-gadget: report suspend, resume, reset, and disconnect events andrey.konovalov
2023-10-26 16:36   ` Andrey Konovalov

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