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From:   Marek Szyprowski <m.szyprowski@samsung.com>
To:     dmaengine@vger.kernel.org, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@samsung.com>,
        Mark Brown <broonie@kernel.org>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Vinod Koul <vkoul@kernel.org>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Peter Ujfalusi <peter.ujfalusi@ti.com>
Subject: [PATCH v2] dmaengine: Fix return value for dma_requrest_chan() in
 case of failure
Date:   Thu, 30 Jan 2020 08:08:34 +0100
Message-Id: <20200130070834.17537-1-m.szyprowski@samsung.com>
Content-Type: text/plain; charset="utf-8"
CMS-TYPE: 201P
References: <CGME20200130070850eucas1p1a7a09e2bec2f6fe652f206b61a8a04ae@eucas1p1.samsung.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Commit 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and
slaves") changed the dma_request_chan() function flow in such a way that
it always returns EPROBE_DEFER in case of channels that cannot be found.
This break the operation of the devices which have optional DMA channels
as it puts their drivers in endless deferred probe loop. Fix this by
propagating the proper error value.

Fixes: 71723a96b8b1 ("dmaengine: Create symlinks between DMA channels and slaves")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/dma/dmaengine.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index f3ef4edd4de1..7b1cefc3213a 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -759,7 +759,7 @@ struct dma_chan *dma_request_chan(struct device *dev, const char *name)
 	if (!IS_ERR_OR_NULL(chan))
 		goto found;
 
-	return ERR_PTR(-EPROBE_DEFER);
+	return chan ? chan : ERR_PTR(-EPROBE_DEFER);
 
 found:
 	chan->slave = dev;
-- 
2.17.1