Thread (1 message) 1 message, 1 author, 2018-06-20

[08/27] media: em28xx-audio: use irqsave() in USB's complete callback

flat view
STALE2988d

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2018-06-20 11:01:31
Also in: linux-media
Subsystem: em28xx video4linux driver, media input infrastructure (v4l/dvb), the rest · Maintainers: Mauro Carvalho Chehab, Linus Torvalds

The USB completion callback does not disable interrupts while acquiring
the lock. We want to remove the local_irq_disable() invocation from
__usb_hcd_giveback_urb() and therefore it is required for the callback
handler to disable the interrupts while acquiring the lock.
The callback may be invoked either in IRQ or BH context depending on the
USB host controller.
Use the _irqsave() variant of the locking primitives.

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/media/usb/em28xx/em28xx-audio.c | 5 +++--
 drivers/media/usb/em28xx/em28xx-core.c  | 5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c
index bb510cf8fbbb..7f75002927a1 100644
--- a/drivers/media/usb/em28xx/em28xx-audio.c
+++ b/drivers/media/usb/em28xx/em28xx-audio.c
@@ -116,6 +116,7 @@ static void em28xx_audio_isocirq(struct urb *urb)
 		stride = runtime->frame_bits >> 3;
 
 		for (i = 0; i < urb->number_of_packets; i++) {
+			unsigned long flags;
 			int length =
 			    urb->iso_frame_desc[i].actual_length / stride;
 			cp = (unsigned char *)urb->transfer_buffer +
@@ -137,7 +138,7 @@ static void em28xx_audio_isocirq(struct urb *urb)
 				       length * stride);
 			}
 
-			snd_pcm_stream_lock(substream);
+			snd_pcm_stream_lock_irqsave(substream, flags);
 
 			dev->adev.hwptr_done_capture += length;
 			if (dev->adev.hwptr_done_capture >=
@@ -153,7 +154,7 @@ static void em28xx_audio_isocirq(struct urb *urb)
 				period_elapsed = 1;
 			}
 
-			snd_pcm_stream_unlock(substream);
+			snd_pcm_stream_unlock_irqrestore(substream, flags);
 		}
 		if (period_elapsed)
 			snd_pcm_period_elapsed(substream);
diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c
index f70845e7d8c6..ec6e5152afd9 100644
--- a/drivers/media/usb/em28xx/em28xx-core.c
+++ b/drivers/media/usb/em28xx/em28xx-core.c
@@ -777,6 +777,7 @@ EXPORT_SYMBOL_GPL(em28xx_set_mode);
 static void em28xx_irq_callback(struct urb *urb)
 {
 	struct em28xx *dev = urb->context;
+	unsigned long flags;
 	int i;
 
 	switch (urb->status) {
@@ -793,9 +794,9 @@ static void em28xx_irq_callback(struct urb *urb)
 	}
 
 	/* Copy data from URB */
-	spin_lock(&dev->slock);
+	spin_lock_irqsave(&dev->slock, flags);
 	dev->usb_ctl.urb_data_copy(dev, urb);
-	spin_unlock(&dev->slock);
+	spin_unlock_irqrestore(&dev->slock, flags);
 
 	/* Reset urb buffers */
 	for (i = 0; i < urb->number_of_packets; i++) {
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help