6.15-stable review patch. If anyone has any objections, please let me know.
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From: Charles Keepax ckeepax@opensource.cirrus.com
[ Upstream commit ccb7bb13c00bcc3178d270da052635c56148bc16 ]
The sdw_dev_lock protects the SoundWire driver callbacks against the probed flag, which is used to skip the callbacks if the driver gets removed. For more information see commit bd29c00edd0a ("soundwire: revisit driver bind/unbind and callbacks").
However, this lock is a frequent source of mutex inversions. Many audio operations eventually hit the hardware resulting in a SoundWire callback, this means that typically the driver has the locking order ALSA/ASoC locks -> sdw_dev_lock. Conversely, the IRQ comes in directly from the SoundWire hardware, but then will often want to access ALSA/ASoC, such as updating something in DAPM or an ALSA control. This gives the other lock order sdw_dev_lock -> ALSA/ASoC locks.
When the IRQ handling was initially added to SoundWire this was through a callback mechanism. As such it required being covered by the lock because the callbacks are part of the sdw_driver structure and are thus present regardless of if the driver is currently probed.
Since then a newer mechanism using the IRQ framework has been added, which is currently covered by the same lock but this isn't actually required. Handlers for the IRQ framework are registered in probe and should by released during remove, thus the IRQ framework will have already unbound the IRQ before the slave driver is removed. Avoid the aforementioned mutex inversion by moving the handle_nested_irq call outside of the sdw_dev_lock.
Signed-off-by: Charles Keepax ckeepax@opensource.cirrus.com Link: https://lore.kernel.org/r/20250609143041.495049-3-ckeepax@opensource.cirrus.... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/soundwire/bus.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c index 39aecd34c641..1a70f80c2514 100644 --- a/drivers/soundwire/bus.c +++ b/drivers/soundwire/bus.c @@ -1756,15 +1756,15 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
/* Update the Slave driver */ if (slave_notify) { + if (slave->prop.use_domain_irq && slave->irq) + handle_nested_irq(slave->irq); + mutex_lock(&slave->sdw_dev_lock);
if (slave->probed) { struct device *dev = &slave->dev; struct sdw_driver *drv = drv_to_sdw_driver(dev->driver);
- if (slave->prop.use_domain_irq && slave->irq) - handle_nested_irq(slave->irq); - if (drv->ops && drv->ops->interrupt_callback) { slave_intr.sdca_cascade = sdca_cascade; slave_intr.control_port = clear;