USB: xhci: drop workaround for forced irq threading

Force-threaded interrupt handlers used to run with interrupts enabled,
something which could lead to deadlocks in case a threaded handler
shared a lock with code running in hard interrupt context (e.g. timer
callbacks) and did not explicitly disable interrupts.

Since commit 81e2073c175b ("genirq: Disable interrupts for force
threaded handlers") interrupt handlers always run with interrupts
disabled on non-RT so that drivers no longer need to do handle forced
threading ("threadirqs").

Drop the now obsolete workaround added by commit 63aea0dbab90 ("USB:
xhci: fix lock-inversion problem").

Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322111140.32056-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 65dba0fba605bd3468f1833a49540a56a024c317..1eee60ac518f5ed8edaf531fd35583a187022e55 100644 (file)
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -3014,12 +3014,11 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
        union xhci_trb *event_ring_deq;
        irqreturn_t ret = IRQ_NONE;
-       unsigned long flags;
        u64 temp_64;
        u32 status;
        int event_loop = 0;
 
-       spin_lock_irqsave(&xhci->lock, flags);
+       spin_lock(&xhci->lock);
        /* Check if the xHC generated the interrupt, or the irq is shared */
        status = readl(&xhci->op_regs->status);
        if (status == ~(u32)0) {
@@ -3082,7 +3081,7 @@ irqreturn_t xhci_irq(struct usb_hcd *hcd)
        ret = IRQ_HANDLED;
 
 out:
-       spin_unlock_irqrestore(&xhci->lock, flags);
+       spin_unlock(&xhci->lock);
 
        return ret;
 }