dmaengine: idxd: create user driver for wq 'device'

The original architecture of /sys/bus/dsa invented a scheme whereby a
single entry in the list of bus drivers, /sys/bus/drivers/dsa, handled
all device types and internally routed them to different drivers.
Those internal drivers were invisible to userspace. Now, as
/sys/bus/dsa wants to grow support for alternate drivers for a given
device, for example vfio-mdev instead of kernel-internal-dmaengine, a
proper bus device-driver model is needed. The first step in that process
is separating the existing omnibus/implicit "dsa" driver into proper
individual drivers registered on /sys/bus/dsa. Establish the
idxd_user_drv driver that controls the enabling and disabling of the
wq and also register and unregister a char device to allow user space
to mmap the descriptor submission portal.

The cdev related bits are moved to the cdev driver probe/remove and out of
the drv_enabe/disable_wq() calls. These bits are exclusive to the cdev
operation and not part of the generic enable/disable of the wq device.

Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162637467578.744545.10203997610072341376.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/idxd/cdev.c b/drivers/dma/idxd/cdev.c
index 18a003b93812ae6fc1e72796a7449c210c8f01a4..b67bbf24242a2c6fe97f73724d090a23f4ff5c16 100644 (file)
--- a/drivers/dma/idxd/cdev.c
+++ b/drivers/dma/idxd/cdev.c
@@ -304,6 +304,59 @@ void idxd_wq_del_cdev(struct idxd_wq *wq)
        put_device(cdev_dev(idxd_cdev));
 }
 
+static int idxd_user_drv_probe(struct idxd_dev *idxd_dev)
+{
+       struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
+       struct idxd_device *idxd = wq->idxd;
+       int rc;
+
+       if (idxd->state != IDXD_DEV_ENABLED)
+               return -ENXIO;
+
+       mutex_lock(&wq->wq_lock);
+       wq->type = IDXD_WQT_USER;
+       rc = __drv_enable_wq(wq);
+       if (rc < 0)
+               goto err;
+
+       rc = idxd_wq_add_cdev(wq);
+       if (rc < 0)
+               goto err_cdev;
+
+       mutex_unlock(&wq->wq_lock);
+       return 0;
+
+err_cdev:
+       __drv_disable_wq(wq);
+err:
+       wq->type = IDXD_WQT_NONE;
+       mutex_unlock(&wq->wq_lock);
+       return rc;
+}
+
+static void idxd_user_drv_remove(struct idxd_dev *idxd_dev)
+{
+       struct idxd_wq *wq = idxd_dev_to_wq(idxd_dev);
+
+       mutex_lock(&wq->wq_lock);
+       idxd_wq_del_cdev(wq);
+       __drv_disable_wq(wq);
+       wq->type = IDXD_WQT_NONE;
+       mutex_unlock(&wq->wq_lock);
+}
+
+static enum idxd_dev_type dev_types[] = {
+       IDXD_DEV_WQ,
+       IDXD_DEV_NONE,
+};
+
+struct idxd_device_driver idxd_user_drv = {
+       .probe = idxd_user_drv_probe,
+       .remove = idxd_user_drv_remove,
+       .name = "user",
+       .type = dev_types,
+};
+
 int idxd_cdev_register(void)
 {
        int rc, i;

diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
index 4dcc9431ae3d37608f65b0d20f77d84a5cd851dd..9bbc28d9a9eb28d4f13c93bed3c516613c3794e6 100644 (file)
--- a/drivers/dma/idxd/device.c
+++ b/drivers/dma/idxd/device.c
@@ -1201,19 +1201,8 @@ int __drv_enable_wq(struct idxd_wq *wq)
        }
 
        wq->client_count = 0;
-
-       if (is_idxd_wq_cdev(wq)) {
-               rc = idxd_wq_add_cdev(wq);
-               if (rc < 0) {
-                       dev_dbg(dev, "wq %d cdev creation failed\n", wq->id);
-                       goto err_client;
-               }
-       }
-
        return 0;
 
-err_client:
-       idxd_wq_unmap_portal(wq);
 err_map_portal:
        rc = idxd_wq_disable(wq, false);
        if (rc < 0)
@@ -1239,9 +1228,6 @@ void __drv_disable_wq(struct idxd_wq *wq)
 
        lockdep_assert_held(&wq->wq_lock);
 
-       if (is_idxd_wq_cdev(wq))
-               idxd_wq_del_cdev(wq);
-
        if (idxd_wq_refcount(wq))
                dev_warn(dev, "Clients has claim on wq %d: %d\n",
                         wq->id, idxd_wq_refcount(wq));

diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index a840c328bec90b77952f8018bfb8baa804467524..bacec9b93a7e39a2cfb12aa51a341ae612b3490f 100644 (file)
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -60,6 +60,7 @@ struct idxd_device_driver {
 extern struct idxd_device_driver dsa_drv;
 extern struct idxd_device_driver idxd_drv;
 extern struct idxd_device_driver idxd_dmaengine_drv;
+extern struct idxd_device_driver idxd_user_drv;
 
 struct idxd_irq_entry {
        struct idxd_device *idxd;

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 6f38128ce400eea51d2146adeca7772a0f714d7c..33a80f700ff8d2fd38eca05f96dc10a702f7a2ae 100644 (file)
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -848,6 +848,10 @@ static int __init idxd_init_module(void)
        if (err < 0)
                goto err_idxd_dmaengine_driver_register;
 
+       err = idxd_driver_register(&idxd_user_drv);
+       if (err < 0)
+               goto err_idxd_user_driver_register;
+
        err = idxd_driver_register(&dsa_drv);
        if (err < 0)
                goto err_dsa_driver_register;
@@ -867,6 +871,8 @@ err_pci_register:
 err_cdev_register:
        idxd_driver_unregister(&dsa_drv);
 err_dsa_driver_register:
+       idxd_driver_unregister(&idxd_user_drv);
+err_idxd_user_driver_register:
        idxd_driver_unregister(&idxd_dmaengine_drv);
 err_idxd_dmaengine_driver_register:
        idxd_driver_unregister(&idxd_drv);
@@ -878,6 +884,7 @@ module_init(idxd_init_module);
 
 static void __exit idxd_exit_module(void)
 {
+       idxd_driver_unregister(&idxd_user_drv);
        idxd_driver_unregister(&idxd_dmaengine_drv);
        idxd_driver_unregister(&idxd_drv);
        idxd_driver_unregister(&dsa_drv);