From eb8df543e444492328f506adffc7dfe94111f1bd Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Fri, 5 May 2017 11:57:44 +0200
Subject: dmaengine: mv_xor_v2: handle mv_xor_v2_prep_sw_desc() error properly

The mv_xor_v2_prep_sw_desc() is called from a few different places in
the driver, but we never take into account the fact that it might
return NULL. This commit fixes that, ensuring that we don't panic if
there are no more descriptors available.

Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver")
Cc: <stable@vger.kernel.org>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
---
 drivers/dma/mv_xor_v2.c | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'drivers/dma/mv_xor_v2.c')

diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
index a28a01fcba67..e9280207ac19 100644
--- a/drivers/dma/mv_xor_v2.c
+++ b/drivers/dma/mv_xor_v2.c
@@ -389,6 +389,8 @@ mv_xor_v2_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest,
 		__func__, len, &src, &dest, flags);
 
 	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+	if (!sw_desc)
+		return NULL;
 
 	sw_desc->async_tx.flags = flags;
 
@@ -443,6 +445,8 @@ mv_xor_v2_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
 		__func__, src_cnt, len, &dest, flags);
 
 	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+	if (!sw_desc)
+		return NULL;
 
 	sw_desc->async_tx.flags = flags;
 
@@ -491,6 +495,8 @@ mv_xor_v2_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags)
 		container_of(chan, struct mv_xor_v2_device, dmachan);
 
 	sw_desc = mv_xor_v2_prep_sw_desc(xor_dev);
+	if (!sw_desc)
+		return NULL;
 
 	/* set the HW descriptor */
 	hw_descriptor = &sw_desc->hw_desc;
-- 
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