[v3,11/12] dmaengine: at_xdmac: Remove a level of indentation in at_xdmac_tasklet()

Commit Message

Tudor Ambarus Dec. 15, 2021, 11:01 a.m. UTC

Apart of making the code easier to read, this patch is a prerequisite for
a functional change: tasklets run with interrupts enabled, so we need to
protect atchan->irq_status with spin_lock_irq() otherwise the tasklet can
be interrupted by the IRQ that modifies irq_status. atchan->irq_status
will be protected in a further patch.

Signed-off-by: Tudor Ambarus <[e-mail]>
---
 drivers/dma/at_xdmac.c | 70 ++++++++++++++++++++----------------------
 1 file changed, 34 insertions(+), 36 deletions(-)

Patch

diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c
index abe8c4615e65..ba727751a9f6 100644
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1667,53 +1667,51 @@  static void at_xdmac_tasklet(struct tasklet_struct *t)
 {
 	struct at_xdmac_chan	*atchan = from_tasklet(atchan, t, tasklet);
 	struct at_xdmac_desc	*desc;
+	struct dma_async_tx_descriptor *txd;
 	u32			error_mask;
 
 	dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n",
 		__func__, atchan->irq_status);
 
-	error_mask = AT_XDMAC_CIS_RBEIS
-		     | AT_XDMAC_CIS_WBEIS
-		     | AT_XDMAC_CIS_ROIS;
-
-	if (at_xdmac_chan_is_cyclic(atchan)) {
-		at_xdmac_handle_cyclic(atchan);
-	} else if ((atchan->irq_status & AT_XDMAC_CIS_LIS)
-		   || (atchan->irq_status & error_mask)) {
-		struct dma_async_tx_descriptor  *txd;
-
-		if (atchan->irq_status & error_mask)
-			at_xdmac_handle_error(atchan);
-
-		spin_lock_irq(&atchan->lock);
-		desc = list_first_entry(&atchan->xfers_list,
-					struct at_xdmac_desc,
-					xfer_node);
-		dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
-		if (!desc->active_xfer) {
-			dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
-			spin_unlock_irq(&atchan->lock);
-			return;
-		}
+	if (at_xdmac_chan_is_cyclic(atchan))
+		return at_xdmac_handle_cyclic(atchan);
 
-		txd = &desc->tx_dma_desc;
-		dma_cookie_complete(txd);
-		/* Remove the transfer from the transfer list. */
-		list_del(&desc->xfer_node);
-		spin_unlock_irq(&atchan->lock);
+	error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS |
+		AT_XDMAC_CIS_ROIS;
 
-		if (txd->flags & DMA_PREP_INTERRUPT)
-			dmaengine_desc_get_callback_invoke(txd, NULL);
+	if (!(atchan->irq_status & AT_XDMAC_CIS_LIS) &&
+	    !(atchan->irq_status & error_mask))
+		return;
 
-		dma_run_dependencies(txd);
+	if (atchan->irq_status & error_mask)
+		at_xdmac_handle_error(atchan);
 
-		spin_lock_irq(&atchan->lock);
-		/* Move the xfer descriptors into the free descriptors list. */
-		list_splice_tail_init(&desc->descs_list,
-				      &atchan->free_descs_list);
-		at_xdmac_advance_work(atchan);
+	spin_lock_irq(&atchan->lock);
+	desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
+				xfer_node);
+	dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc);
+	if (!desc->active_xfer) {
+		dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting");
 		spin_unlock_irq(&atchan->lock);
+		return;
 	}
+
+	txd = &desc->tx_dma_desc;
+	dma_cookie_complete(txd);
+	/* Remove the transfer from the transfer list. */
+	list_del(&desc->xfer_node);
+	spin_unlock_irq(&atchan->lock);
+
+	if (txd->flags & DMA_PREP_INTERRUPT)
+		dmaengine_desc_get_callback_invoke(txd, NULL);
+
+	dma_run_dependencies(txd);
+
+	spin_lock_irq(&atchan->lock);
+	/* Move the xfer descriptors into the free descriptors list. */
+	list_splice_tail_init(&desc->descs_list, &atchan->free_descs_list);
+	at_xdmac_advance_work(atchan);
+	spin_unlock_irq(&atchan->lock);
 }
 
 static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)