[PATCH v5 1/4] dmaengine: add dma_device_get() helper

[Shivank Garg <shivankg@amd.com>]

Add dma_device_get() helper to match dma_device_put() to make code
symmetric. It wraps open-coded kref_get_unless_zero() and asserts that
dma_list_mutex is held, matching its put counterpart.

No functional change intended.

Suggested-by: Frank Li <Frank.Li@nxp.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Shivank Garg <shivankg@amd.com>
---
 drivers/dma/dmaengine.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index 9049171df857..cb3b7bccce1f 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -433,6 +433,12 @@ static void dma_device_release(struct kref *ref)
 		device->device_release(device);
 }
 
+static int __must_check dma_device_get(struct dma_device *device)
+{
+	lockdep_assert_held(&dma_list_mutex);
+	return kref_get_unless_zero(&device->ref);
+}
+
 static void dma_device_put(struct dma_device *device)
 {
 	lockdep_assert_held(&dma_list_mutex);
@@ -460,8 +466,7 @@ static int dma_chan_get(struct dma_chan *chan)
 	if (!try_module_get(owner))
 		return -ENODEV;
 
-	ret = kref_get_unless_zero(&chan->device->ref);
-	if (!ret) {
+	if (!dma_device_get(chan->device)) {
 		ret = -ENODEV;
 		goto module_put_out;
 	}

-- 
2.43.0