dmaengine: xilinx: xdma: Fix data synchronisation in xdma_channel_isr()

Requests the vchan lock before using xdma->stop_request.

Fixes: 6a40fb8 ("dmaengine: xilinx: xdma: Fix synchronization issue")
Cc: stable@vger.kernel.org
Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com>
Link: https://lore.kernel.org/r/20240607-xdma-fixes-v2-1-0282319ce345@bootlin.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: Fomys

drivers/dma/xilinx/xdma.c

@@ -885,11 +885,11 @@ static irqreturn_t xdma_channel_isr(int irq, void *dev_id)
 	u32 st;
 	bool repeat_tx;
 
+	spin_lock(&xchan->vchan.lock);
+
 	if (xchan->stop_requested)
 		complete(&xchan->last_interrupt);
 
-	spin_lock(&xchan->vchan.lock);
-
 	/* get submitted request */
 	vd = vchan_next_desc(&xchan->vchan);
 	if (!vd)