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>

diff --git a/drivers/dma/mv_xor_v2.c b/drivers/dma/mv_xor_v2.c
index a28a01fcba674dc569e4d49ca6fd50def5a58645..e9280207ac19bd1ea4bb0d33f1e717600240126a 100644 (file)
--- 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;