linux-kernel - [PATCH 4.11 061/150] dmaengine: mv_xor_v2: do not use descriptors not acked by async

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Date:   Mon, 12 Jun 2017 17:24:28 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>,
        Vinod Koul <vinod.koul@...el.com>
Subject: [PATCH 4.11 061/150] dmaengine: mv_xor_v2: do not use descriptors not acked by async_tx

4.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>

commit bc473da1ed726c975ad47f8d7d27631de11356d8 upstream.

Descriptors that have not been acknowledged by the async_tx layer
should not be re-used, so this commit adjusts the implementation of
mv_xor_v2_prep_sw_desc() to skip descriptors for which
async_tx_test_ack() is false.

Fixes: 19a340b1a820 ("dmaengine: mv_xor_v2: new driver")
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@...e-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@...el.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/dma/mv_xor_v2.c |   32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

--- a/drivers/dma/mv_xor_v2.c
+++ b/drivers/dma/mv_xor_v2.c
@@ -344,6 +344,7 @@ static struct mv_xor_v2_sw_desc	*
 mv_xor_v2_prep_sw_desc(struct mv_xor_v2_device *xor_dev)
 {
 	struct mv_xor_v2_sw_desc *sw_desc;
+	bool found = false;
 
 	/* Lock the channel */
 	spin_lock_bh(&xor_dev->lock);
@@ -355,19 +356,23 @@ mv_xor_v2_prep_sw_desc(struct mv_xor_v2_
 		return NULL;
 	}
 
-	/* get a free SW descriptor from the SW DESQ */
-	sw_desc = list_first_entry(&xor_dev->free_sw_desc,
-				   struct mv_xor_v2_sw_desc, free_list);
+	list_for_each_entry(sw_desc, &xor_dev->free_sw_desc, free_list) {
+		if (async_tx_test_ack(&sw_desc->async_tx)) {
+			found = true;
+			break;
+		}
+	}
+
+	if (!found) {
+		spin_unlock_bh(&xor_dev->lock);
+		return NULL;
+	}
+
 	list_del(&sw_desc->free_list);
 
 	/* Release the channel */
 	spin_unlock_bh(&xor_dev->lock);
 
-	/* set the async tx descriptor */
-	dma_async_tx_descriptor_init(&sw_desc->async_tx, &xor_dev->dmachan);
-	sw_desc->async_tx.tx_submit = mv_xor_v2_tx_submit;
-	async_tx_ack(&sw_desc->async_tx);
-
 	return sw_desc;
 }
 
@@ -785,8 +790,15 @@ static int mv_xor_v2_probe(struct platfo
 
 	/* add all SW descriptors to the free list */
 	for (i = 0; i < MV_XOR_V2_DESC_NUM; i++) {
-		xor_dev->sw_desq[i].idx = i;
-		list_add(&xor_dev->sw_desq[i].free_list,
+		struct mv_xor_v2_sw_desc *sw_desc =
+			xor_dev->sw_desq + i;
+		sw_desc->idx = i;
+		dma_async_tx_descriptor_init(&sw_desc->async_tx,
+					     &xor_dev->dmachan);
+		sw_desc->async_tx.tx_submit = mv_xor_v2_tx_submit;
+		async_tx_ack(&sw_desc->async_tx);
+
+		list_add(&sw_desc->free_list,
 			 &xor_dev->free_sw_desc);
 	}