dmaengine: idxd: Flush all pending descriptors

When used as a dmaengine, the DMA "core" might ask the driver to
terminate all pending requests, when that happens, flush all pending
descriptors.

In this context, flush means removing the requests from the pending
lists, so even if they are completed after, the user is not notified.

Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Link: https://patch.msgid.link/20260121-idxd-fix-flr-on-kernel-queues-v3-v3-5-7ed70658a9d1@intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: vcgomes

drivers/dma/idxd/dma.c

@@ -194,6 +194,15 @@ static void idxd_dma_release(struct dma_device *device)
 	kfree(idxd_dma);
 }
 
+static int idxd_dma_terminate_all(struct dma_chan *c)
+{
+	struct idxd_wq *wq = to_idxd_wq(c);
+
+	idxd_wq_flush_descs(wq);
+
+	return 0;
+}
+
 int idxd_register_dma_device(struct idxd_device *idxd)
 {
 	struct idxd_dma_dev *idxd_dma;
@@ -224,6 +233,7 @@ int idxd_register_dma_device(struct idxd_device *idxd)
 	dma->device_issue_pending = idxd_dma_issue_pending;
 	dma->device_alloc_chan_resources = idxd_dma_alloc_chan_resources;
 	dma->device_free_chan_resources = idxd_dma_free_chan_resources;
+	dma->device_terminate_all = idxd_dma_terminate_all;
 
 	rc = dma_async_device_register(dma);
 	if (rc < 0) {