linux-kernel - [PATCH 1/3] dmaengine: at_xdmac: remove BUG

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Message-ID: <324b91c71a148a7694d28d9b8b4364095d9b0ebe.1549364323.git.nicolas.ferre@microchip.com>
Date:   Tue, 5 Feb 2019 12:03:41 +0100
From:   Nicolas Ferre <nicolas.ferre@...rochip.com>
To:     Ludovic Desroches <ludovic.desroches@...rochip.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <dmaengine@...r.kernel.org>, "Vinod Koul" <vkoul@...nel.org>
CC:     Alexandre Belloni <alexandre.belloni@...tlin.com>,
        <linux-kernel@...r.kernel.org>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>
Subject: [PATCH 1/3] dmaengine: at_xdmac: remove BUG_ON macro in tasklet

Even if this case shouldn't happen when controller is properly programmed,
it's still better to avoid dumping a kernel Oops for this.
As the sequence may happen only for debugging purposes, log the error and
just finish the tasklet call.

Signed-off-by: Nicolas Ferre <nicolas.ferre@...rochip.com>
---
 drivers/dma/at_xdmac.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index fe69dccfa0c0..37a269420435 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1606,7 +1606,11 @@ static void at_xdmac_tasklet(unsigned long data)
 					struct at_xdmac_desc,
 					xfer_node);
 		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
-		BUG_ON(!desc->active_xfer);
+		if (!desc->active_xfer) {
+			dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
+			spin_unlock_bh(&atchan->lock);
+			return;
+		}
 
 		txd = &desc->tx_dma_desc;
 
-- 
2.17.1