[PATCH -next] spi/topcliff_pch: Fix potential NULL dereference on allocation error

[YueHaibing]

In pch_spi_handle_dma, it doesn't check for NULL returns of kcalloc
so it would result in an Oops.

Fixes: c37f3c2749b5 ("spi/topcliff_pch: DMA support")
Signed-off-by: YueHaibing <yuehaib...@huawei.com>
---
 drivers/spi/spi-topcliff-pch.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/spi/spi-topcliff-pch.c b/drivers/spi/spi-topcliff-pch.c
index 97d1375..e7e8ea1 100644
--- a/drivers/spi/spi-topcliff-pch.c
+++ b/drivers/spi/spi-topcliff-pch.c
@@ -1008,6 +1008,9 @@ static void pch_spi_handle_dma(struct pch_spi_data *data, 
int *bpw)
 
        /* RX */
        dma->sg_rx_p = kcalloc(num, sizeof(*dma->sg_rx_p), GFP_ATOMIC);
+       if (!dma->sg_rx_p)
+               return;
+
        sg_init_table(dma->sg_rx_p, num); /* Initialize SG table */
        /* offset, length setting */
        sg = dma->sg_rx_p;
@@ -1068,6 +1071,9 @@ static void pch_spi_handle_dma(struct pch_spi_data *data, 
int *bpw)
        }
 
        dma->sg_tx_p = kcalloc(num, sizeof(*dma->sg_tx_p), GFP_ATOMIC);
+       if (!dma->sg_tx_p)
+               return;
+
        sg_init_table(dma->sg_tx_p, num); /* Initialize SG table */
        /* offset, length setting */
        sg = dma->sg_tx_p;
-- 
2.7.0