soc: ti: k3-ringacc: Add try_module_get() to k3_dmaring_request_dual_ring()

When the k3 ring accelerator driver has been modified to add module build
support, try_module_get() and module_put() have been added to update the
module refcnt. One code path has not been updated and it has introduced
an issue where the refcnt is decremented by module_put() in
k3_ringacc_ring_free() without being incremented previously.
Adding try_module_get() to k3_dmaring_request_dual_ring() ensures the
refcnt is kept up to date.

Fixes: c07f216a8b72 ("soc: ti: k3-ringacc: Allow the driver to be built as module")
Signed-off-by: Nicolas Frayer <nfrayer@baylibre.com>
Reviewed-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>
Link: https://lore.kernel.org/r/20221230001404.10902-1-nfrayer@baylibre.com
Signed-off-by: Nishanth Menon <nm@ti.com>

diff --git a/drivers/soc/ti/k3-ringacc.c b/drivers/soc/ti/k3-ringacc.c
index e01e4d8..8f13136 100644 (file)
--- a/drivers/soc/ti/k3-ringacc.c
+++ b/drivers/soc/ti/k3-ringacc.c
@@ -406,6 +406,11 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id,
 
        mutex_lock(&ringacc->req_lock);
 
+       if (!try_module_get(ringacc->dev->driver->owner)) {
+               ret = -EINVAL;
+               goto err_module_get;
+       }
+
        if (test_bit(fwd_id, ringacc->rings_inuse)) {
                ret = -EBUSY;
                goto error;
@@ -421,6 +426,8 @@ static int k3_dmaring_request_dual_ring(struct k3_ringacc *ringacc, int fwd_id,
        return 0;
 
 error:
+       module_put(ringacc->dev->driver->owner);
+err_module_get:
        mutex_unlock(&ringacc->req_lock);
        return ret;
 }