dmaengine: idxd: add work queue drain support

Add wq drain support. When a wq is being released, it needs to wait for
all in-flight operation to complete.  A device control function
idxd_wq_drain() has been added to facilitate this. A wq drain call
is added to the char dev on release to make sure all user operations are
complete. A wq drain is also added before the wq is being disabled.

A drain command can take an unpredictable period of time. Interrupt support
for device commands is added to allow waiting on the command to
finish. If a previous command is in progress, the new submitter can block
until the current command is finished before proceeding. The interrupt
based submission will submit the command and then wait until a command
completion interrupt happens to complete. All commands are moved to the
interrupt based command submission except for the device reset during
probe, which will be polled.

Fixes: 42d279f9137a ("dmaengine: idxd: add char driver to expose submission portal to userland")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/r/159319502515.69593.13451647706946040301.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 4 insertions, 16 deletions

diff --git a/drivers/dma/idxd/sysfs.c b/drivers/dma/idxd/sysfs.c
index 052dae5d6ddd..6f0711a822a1 100644
--- a/drivers/dma/idxd/sysfs.c
+++ b/drivers/dma/idxd/sysfs.c
@@ -118,12 +118,11 @@ static int idxd_config_bus_probe(struct device *dev)
 		if (!try_module_get(THIS_MODULE))
 			return -ENXIO;
 
-		spin_lock_irqsave(&idxd->dev_lock, flags);
-
 		/* Perform IDXD configuration and enabling */
+		spin_lock_irqsave(&idxd->dev_lock, flags);
 		rc = idxd_device_config(idxd);
+		spin_unlock_irqrestore(&idxd->dev_lock, flags);
 		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			module_put(THIS_MODULE);
 			dev_warn(dev, "Device config failed: %d\n", rc);
 			return rc;
@@ -132,18 +131,15 @@ static int idxd_config_bus_probe(struct device *dev)
 		/* start device */
 		rc = idxd_device_enable(idxd);
 		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			module_put(THIS_MODULE);
 			dev_warn(dev, "Device enable failed: %d\n", rc);
 			return rc;
 		}
 
-		spin_unlock_irqrestore(&idxd->dev_lock, flags);
 		dev_info(dev, "Device %s enabled\n", dev_name(dev));
 
 		rc = idxd_register_dma_device(idxd);
 		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			module_put(THIS_MODULE);
 			dev_dbg(dev, "Failed to register dmaengine device\n");
 			return rc;
@@ -188,8 +184,8 @@ static int idxd_config_bus_probe(struct device *dev)
 
 		spin_lock_irqsave(&idxd->dev_lock, flags);
 		rc = idxd_device_config(idxd);
+		spin_unlock_irqrestore(&idxd->dev_lock, flags);
 		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			mutex_unlock(&wq->wq_lock);
 			dev_warn(dev, "Writing WQ %d config failed: %d\n",
 				 wq->id, rc);
@@ -198,13 +194,11 @@ static int idxd_config_bus_probe(struct device *dev)
 
 		rc = idxd_wq_enable(wq);
 		if (rc < 0) {
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			mutex_unlock(&wq->wq_lock);
 			dev_warn(dev, "WQ %d enabling failed: %d\n",
 				 wq->id, rc);
 			return rc;
 		}
-		spin_unlock_irqrestore(&idxd->dev_lock, flags);
 
 		rc = idxd_wq_map_portal(wq);
 		if (rc < 0) {
@@ -212,7 +206,6 @@ static int idxd_config_bus_probe(struct device *dev)
 			rc = idxd_wq_disable(wq);
 			if (rc < 0)
 				dev_warn(dev, "IDXD wq disable failed\n");
-			spin_unlock_irqrestore(&idxd->dev_lock, flags);
 			mutex_unlock(&wq->wq_lock);
 			return rc;
 		}
@@ -248,7 +241,6 @@ static void disable_wq(struct idxd_wq *wq)
 {
 	struct idxd_device *idxd = wq->idxd;
 	struct device *dev = &idxd->pdev->dev;
-	unsigned long flags;
 	int rc;
 
 	mutex_lock(&wq->wq_lock);
@@ -269,9 +261,8 @@ static void disable_wq(struct idxd_wq *wq)
 
 	idxd_wq_unmap_portal(wq);
 
-	spin_lock_irqsave(&idxd->dev_lock, flags);
+	idxd_wq_drain(wq);
 	rc = idxd_wq_disable(wq);
-	spin_unlock_irqrestore(&idxd->dev_lock, flags);
 
 	idxd_wq_free_resources(wq);
 	wq->client_count = 0;
@@ -287,7 +278,6 @@ static void disable_wq(struct idxd_wq *wq)
 static int idxd_config_bus_remove(struct device *dev)
 {
 	int rc;
-	unsigned long flags;
 
 	dev_dbg(dev, "%s called for %s\n", __func__, dev_name(dev));
 
@@ -313,9 +303,7 @@ static int idxd_config_bus_remove(struct device *dev)
 		}
 
 		idxd_unregister_dma_device(idxd);
-		spin_lock_irqsave(&idxd->dev_lock, flags);
 		rc = idxd_device_disable(idxd);
-		spin_unlock_irqrestore(&idxd->dev_lock, flags);
 		module_put(THIS_MODULE);
 		if (rc < 0)
 			dev_warn(dev, "Device disable failed\n");