staging: bcm2835-camera: Remove bulk_mutex as it is not required

There is no requirement to serialise bulk transfers as that is all
done in VCHI, and if a second MMAL_MSG_TYPE_BUFFER_TO_HOST happened
before the VCHI_CALLBACK_BULK_RECEIVED, then the service_callback
thread is deadlocked.

Remove the bulk_mutex so that multiple receives can be scheduled at a
time.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
index 037c68b83df9fd151d2c8fc357fbeb8cf0362be3..d6950226551fde33d2dd347080c87682a3e6b070 100644 (file)
--- a/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-camera/mmal-vchiq.c
@@ -162,9 +162,6 @@ struct vchiq_mmal_instance {
        /* ensure serialised access to service */
        struct mutex vchiq_mutex;
 
-       /* ensure serialised access to bulk operations */
-       struct mutex bulk_mutex;
-
        /* vmalloc page to receive scratch bulk xfers into */
        void *bulk_scratch;
 
@@ -332,13 +329,6 @@ static int bulk_receive(struct vchiq_mmal_instance *instance,
        unsigned long flags = 0;
        int ret;
 
-       /* bulk mutex stops other bulk operations while we have a
-        * receive in progress - released in callback
-        */
-       ret = mutex_lock_interruptible(&instance->bulk_mutex);
-       if (ret != 0)
-               return ret;
-
        rd_len = msg->u.buffer_from_host.buffer_header.length;
 
        /* take buffer from queue */
@@ -357,8 +347,6 @@ static int bulk_receive(struct vchiq_mmal_instance *instance,
                 * waiting bulk receive?
                 */
 
-               mutex_unlock(&instance->bulk_mutex);
-
                return -EINVAL;
        }
 
@@ -399,11 +387,6 @@ static int bulk_receive(struct vchiq_mmal_instance *instance,
 
        vchi_service_release(instance->handle);
 
-       if (ret != 0) {
-               /* callback will not be clearing the mutex */
-               mutex_unlock(&instance->bulk_mutex);
-       }
-
        return ret;
 }
 
@@ -413,13 +396,6 @@ static int dummy_bulk_receive(struct vchiq_mmal_instance *instance,
 {
        int ret;
 
-       /* bulk mutex stops other bulk operations while we have a
-        * receive in progress - released in callback
-        */
-       ret = mutex_lock_interruptible(&instance->bulk_mutex);
-       if (ret != 0)
-               return ret;
-
        /* zero length indicates this was a dummy transfer */
        msg_context->u.bulk.buffer_used = 0;
 
@@ -435,11 +411,6 @@ static int dummy_bulk_receive(struct vchiq_mmal_instance *instance,
 
        vchi_service_release(instance->handle);
 
-       if (ret != 0) {
-               /* callback will not be clearing the mutex */
-               mutex_unlock(&instance->bulk_mutex);
-       }
-
        return ret;
 }
 
@@ -494,18 +465,11 @@ buffer_from_host(struct vchiq_mmal_instance *instance,
 
        pr_debug("instance:%p buffer:%p\n", instance->handle, buf);
 
-       /* bulk mutex stops other bulk operations while we
-        * have a receive in progress
-        */
-       if (mutex_lock_interruptible(&instance->bulk_mutex))
-               return -EINTR;
-
        /* get context */
        if (!buf->msg_context) {
                pr_err("%s: msg_context not allocated, buf %p\n", __func__,
                       buf);
-               ret = -EINVAL;
-               goto unlock;
+               return -EINVAL;
        }
        msg_context = buf->msg_context;
 
@@ -559,9 +523,6 @@ buffer_from_host(struct vchiq_mmal_instance *instance,
 
        vchi_service_release(instance->handle);
 
-unlock:
-       mutex_unlock(&instance->bulk_mutex);
-
        return ret;
 }
 
@@ -685,9 +646,6 @@ static void buffer_to_host_cb(struct vchiq_mmal_instance *instance,
 static void bulk_receive_cb(struct vchiq_mmal_instance *instance,
                            struct mmal_msg_context *msg_context)
 {
-       /* bulk receive operation complete */
-       mutex_unlock(&msg_context->u.bulk.instance->bulk_mutex);
-
        /* replace the buffer header */
        port_buffer_from_host(msg_context->u.bulk.instance,
                              msg_context->u.bulk.port);
@@ -703,9 +661,6 @@ static void bulk_abort_cb(struct vchiq_mmal_instance *instance,
 {
        pr_err("%s: bulk ABORTED msg_context:%p\n", __func__, msg_context);
 
-       /* bulk receive operation complete */
-       mutex_unlock(&msg_context->u.bulk.instance->bulk_mutex);
-
        /* replace the buffer header */
        port_buffer_from_host(msg_context->u.bulk.instance,
                              msg_context->u.bulk.port);
@@ -2042,7 +1997,6 @@ int vchiq_mmal_init(struct vchiq_mmal_instance **out_instance)
                return -ENOMEM;
 
        mutex_init(&instance->vchiq_mutex);
-       mutex_init(&instance->bulk_mutex);
 
        instance->bulk_scratch = vmalloc(PAGE_SIZE);