[PATCH v4] ALSA: usx2y: Refuse a retried DSP load after a failure

[YuanZhe Liu]

snd_usx2y_hwdep_dsp_load() sets up the asynchronous sequence URBs and
the interrupt URB when the FPGA firmware image with index 1 is loaded,
and then creates the ALSA devices.  If usx2y_in04_init() or
usx2y_create_alsa_devices() fails, the URBs that were already set up
are left in place.

The core keeps the index unloaded when the callback fails, so user
space may issue the same request again.  The second attempt then enters
usx2y_async_seq04_init() or usx2y_in04_init() with the URBs still
allocated and trips WARN_ON(usx2y->as04.buffer) or
WARN_ON(usx2y->in04_urb).

The URBs cannot be released at this point: the card may already have
registered PCM devices that user space can still open, and the
disconnect handler accesses the URBs without holding the DSP lock.
Mark the chip as hung instead, so that a retried request is refused
with -ENODEV and the assertions keep their meaning.  The URBs are
released by snd_usx2y_card_private_free() when the card is freed.

A failing usx2y_async_seq04_init() still releases its own URBs, so that
path remains retryable.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@xxxxxxxxxxxxxxx
Co-developed-by: Bin Yu <byu@xxxxxxxxxxxxx>
Signed-off-by: Bin Yu <byu@xxxxxxxxxxxxx>
Co-developed-by: Cheng Wen <wencheng@xxxxxxxxxxxxx>
Signed-off-by: Cheng Wen <wencheng@xxxxxxxxxxxxx>
Signed-off-by: YuanZhe Liu <25031212351@xxxxxxxxxxxxxxxxx>
---
v4: drop the release of the URBs on the error paths.  The card may already
    have registered PCM devices, and the disconnect handler accesses the
    URBs without the DSP lock; mark the chip as hung instead and let
    snd_usx2y_card_private_free() release the URBs.

 sound/usb/usx2y/usX2Yhwdep.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sound/usb/usx2y/usX2Yhwdep.c b/sound/usb/usx2y/usX2Yhwdep.c
index 7f153a2fcdd8..3800c5b5887c 100644
--- a/sound/usb/usx2y/usX2Yhwdep.c
+++ b/sound/usb/usx2y/usX2Yhwdep.c
@@ -179,6 +179,9 @@ static int snd_usx2y_hwdep_dsp_load(struct snd_hwdep *hw,
 	int lret, err;
 	char *buf;
 
+	if (priv->chip_status & USX2Y_STAT_CHIP_HUP)
+		return -ENODEV;
+
 	buf = memdup_user(dsp->image, dsp->length);
 	if (IS_ERR(buf))
 		return PTR_ERR(buf);
@@ -201,11 +204,13 @@ static int snd_usx2y_hwdep_dsp_load(struct snd_hwdep *hw,
 		err = usx2y_in04_init(priv);
 		if (err) {
 			dev_err(&dev->dev, "usx2y_in04_init error\n");
+			priv->chip_status |= USX2Y_STAT_CHIP_HUP;
 			return err;
 		}
 		err = usx2y_create_alsa_devices(hw->card);
 		if (err) {
 			dev_err(&dev->dev, "usx2y_create_alsa_devices error %i\n", err);
+			priv->chip_status |= USX2Y_STAT_CHIP_HUP;
 			return err;
 		}
 		priv->chip_status |= USX2Y_STAT_CHIP_INIT;
-- 
2.34.1