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mfd: dln2: Run event handler loop under spinlock 

[ Upstream commit 3d85894225 ]

The event handler loop must be run with interrupts disabled.
Otherwise we will have a warning:

[ 1970.785649] irq 31 handler lineevent_irq_handler+0x0/0x20 enabled interrupts
[ 1970.792739] WARNING: CPU: 0 PID: 0 at kernel/irq/handle.c:159 __handle_irq_event_percpu+0x162/0x170
[ 1970.860732] RIP: 0010:__handle_irq_event_percpu+0x162/0x170
...
[ 1970.946994] Call Trace:
[ 1970.949446]  <IRQ>
[ 1970.951471]  handle_irq_event_percpu+0x2c/0x80
[ 1970.955921]  handle_irq_event+0x23/0x43
[ 1970.959766]  handle_simple_irq+0x57/0x70
[ 1970.963695]  generic_handle_irq+0x42/0x50
[ 1970.967717]  dln2_rx+0xc1/0x210 [dln2]
[ 1970.971479]  ? usb_hcd_unmap_urb_for_dma+0xa6/0x1c0
[ 1970.976362]  __usb_hcd_giveback_urb+0x77/0xe0
[ 1970.980727]  usb_giveback_urb_bh+0x8e/0xe0
[ 1970.984837]  tasklet_action_common.isra.0+0x4a/0xe0
...

Recently xHCI driver switched to tasklets in the commit 36dc01657b
("usb: host: xhci: Support running urb giveback in tasklet context").

The handle_irq_event_* functions are expected to be called with interrupts
disabled and they rightfully complain here because we run in tasklet context
with interrupts enabled.

Use a event spinlock to protect event handler from being interrupted.

Note, that there are only two users of this GPIO and ADC drivers and both of
them are using generic_handle_irq() which makes above happen.

Fixes: 338a128142 ("mfd: Add support for Diolan DLN-2 devices")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Andy Shevchenko 2020-07-23 16:02:46 +03:00 committed by Greg Kroah-Hartman
parent 315b5cbe1a
commit a232699761
1 changed files with 4 additions and 0 deletions
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4
drivers/mfd/dln2.c
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@ -287,7 +287,11 @@ static void dln2_rx(struct urb *urb)
len = urb->actual_length - sizeof(struct dln2_header);
if (handle == DLN2_HANDLE_EVENT) {
unsigned long flags;
spin_lock_irqsave(&dln2->event_cb_lock, flags);
dln2_run_event_callbacks(dln2, id, echo, data, len);
spin_unlock_irqrestore(&dln2->event_cb_lock, flags);
} else {
/* URB will be re-submitted in _dln2_transfer (free_rx_slot) */
if (dln2_transfer_complete(dln2, urb, handle, echo))