[PATCH 3.16 17/61] drivers: usb: core: Minimize irq disabling in usb_sg_cancel()

From: Ben Hutchings
Date: Tue Jun 09 2020 - 14:11:57 EST


3.16.85-rc1 review patch. If anyone has any objections, please let me know.

------------------

From: David Mosberger <davidm@xxxxxxxxxx>

commit 5f2e5fb873e269fcb806165715d237f0de4ecf1d upstream.

Restructure usb_sg_cancel() so we don't have to disable interrupts
while cancelling the URBs.

Suggested-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David Mosberger <davidm@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
drivers/usb/core/message.c | 37 +++++++++++++++++--------------------
1 file changed, 17 insertions(+), 20 deletions(-)

--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -581,31 +581,28 @@ EXPORT_SYMBOL_GPL(usb_sg_wait);
void usb_sg_cancel(struct usb_sg_request *io)
{
unsigned long flags;
+ int i, retval;

spin_lock_irqsave(&io->lock, flags);
+ if (io->status) {
+ spin_unlock_irqrestore(&io->lock, flags);
+ return;
+ }
+ /* shut everything down */
+ io->status = -ECONNRESET;
+ spin_unlock_irqrestore(&io->lock, flags);

- /* shut everything down, if it didn't already */
- if (!io->status) {
- int i;
-
- io->status = -ECONNRESET;
- spin_unlock(&io->lock);
- for (i = 0; i < io->entries; i++) {
- int retval;
-
- usb_block_urb(io->urbs[i]);
+ for (i = io->entries - 1; i >= 0; --i) {
+ usb_block_urb(io->urbs[i]);

- retval = usb_unlink_urb(io->urbs[i]);
- if (retval != -EINPROGRESS
- && retval != -ENODEV
- && retval != -EBUSY
- && retval != -EIDRM)
- dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
- __func__, retval);
- }
- spin_lock(&io->lock);
+ retval = usb_unlink_urb(io->urbs[i]);
+ if (retval != -EINPROGRESS
+ && retval != -ENODEV
+ && retval != -EBUSY
+ && retval != -EIDRM)
+ dev_warn(&io->dev->dev, "%s, unlink --> %d\n",
+ __func__, retval);
}
- spin_unlock_irqrestore(&io->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_sg_cancel);