5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@xxxxxxx>
[ Upstream commit b7df09bb348016943f56b09dcaafe221e3f73947 ]
The USB disconnect callback is supposed to be short and not too-long
waiting. OTOH, the current code uses snd_card_free() at
disconnection, but this waits for the close of all used fds, hence it
can take long. It eventually blocks the upper layer USB ioctls, which
may trigger a soft lockup.
An easy workaround is to replace snd_card_free() with
snd_card_free_when_closed(). This variant returns immediately while
the release of resources is done asynchronously by the card device
release at the last close.
The loop of us122l->mmap_count check is dropped as well. The check is
useless for the asynchronous operation with *_when_closed().
Fixes: 030a07e44129 ("ALSA: Add USB US122L driver")
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Link: https://patch.msgid.link/20241113111042.15058-3-tiwai@xxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
sound/usb/usx2y/us122l.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/sound/usb/usx2y/us122l.c b/sound/usb/usx2y/us122l.c
index e558931cce16e..23d7d542a3de6 100644
--- a/sound/usb/usx2y/us122l.c
+++ b/sound/usb/usx2y/us122l.c
@@ -617,10 +617,7 @@ static void snd_us122l_disconnect(struct usb_interface *intf)
usb_put_intf(usb_ifnum_to_if(us122l->dev, 1));
usb_put_dev(us122l->dev);
- while (atomic_read(&us122l->mmap_count))
- msleep(500);
-
- snd_card_free(card);
+ snd_card_free_when_closed(card);
}
static int snd_us122l_suspend(struct usb_interface *intf, pm_message_t message)
--
2.43.0
