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USB: ehci: drop workaround for forced irq threading

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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 81e2073c17 ("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 a1227f3c10 ("usb:
ehci: fix deadlock when threadirqs option is used").

Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210322111249.32141-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2021-03-22 12:12:49 +01:00 committed by Greg Kroah-Hartman
parent 0b9828763a
commit 8219ab4c9a
1 changed files with 3 additions and 10 deletions
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13
drivers/usb/host/ehci-hcd.c
View file

@ -705,15 +705,8 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
u32 status, masked_status, pcd_status = 0, cmd;
int bh;
unsigned long flags;
/*
* For threadirqs option we use spin_lock_irqsave() variant to prevent
* deadlock with ehci hrtimer callback, because hrtimer callbacks run
* in interrupt context even when threadirqs is specified. We can go
* back to spin_lock() variant when hrtimer callbacks become threaded.
*/
spin_lock_irqsave(&ehci->lock, flags);
spin_lock(&ehci->lock);
status = ehci_readl(ehci, &ehci->regs->status);
@ -731,7 +724,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
/* Shared IRQ? */
if (!masked_status || unlikely(ehci->rh_state == EHCI_RH_HALTED)) {
spin_unlock_irqrestore(&ehci->lock, flags);
spin_unlock(&ehci->lock);
return IRQ_NONE;
}
@ -842,7 +835,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
if (bh)
ehci_work (ehci);
spin_unlock_irqrestore(&ehci->lock, flags);
spin_unlock(&ehci->lock);
if (pcd_status)
usb_hcd_poll_rh_status(hcd);
return IRQ_HANDLED;