dmaengine: at_hdmac: fix potential NULL pointer dereference in atc_prep_dma_interleaved

_xt_ is being dereferenced before it is null checked, hence there is a
potential null pointer dereference.

Fix this by moving the pointer dereference after _xt_ has been null
checked.

This issue was detected with the help of Coccinelle.

Fixes: 4483320e241c ("dmaengine: Use Pointer xt after NULL check.")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
index fbab271b3bf9..a861b5b4d443 100644
--- a/drivers/dma/at_hdmac.c
+++ b/drivers/dma/at_hdmac.c
@@ -708,7 +708,7 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
                          unsigned long flags)
 {
         struct at_dma_chan      *atchan = to_at_dma_chan(chan);
-        struct data_chunk       *first = xt->sgl;
+        struct data_chunk       *first;
         struct at_desc          *desc = NULL;
         size_t                  xfer_count;
         unsigned int            dwidth;
@@ -720,6 +720,8 @@ atc_prep_dma_interleaved(struct dma_chan *chan,
         if (unlikely(!xt || xt->numf != 1 || !xt->frame_size))
                 return NULL;
 
+        first = xt->sgl;
+
         dev_info(chan2dev(chan),
                  "%s: src=%pad, dest=%pad, numf=%d, frame_size=%d, flags=0x%lx\n",
                 __func__, &xt->src_start, &xt->dst_start, xt->numf,