[PATCH v2 1/7] dmaengine: idxd: rework descriptor free path on failure

[Dave Jiang <dave.jiang@xxxxxxxxx>]

Refactor the completion function to allow skipping of descriptor freeing on
the submission failure path. This completely removes descriptor freeing
from the submit failure path and leave the responsibility to the caller.

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
---
 drivers/dma/idxd/dma.c    |   10 ++++++++--
 drivers/dma/idxd/idxd.h   |    8 +-------
 drivers/dma/idxd/init.c   |    9 +++------
 drivers/dma/idxd/irq.c    |    8 ++++----
 drivers/dma/idxd/submit.c |   12 +++---------
 5 files changed, 19 insertions(+), 28 deletions(-)

diff --git a/drivers/dma/idxd/dma.c b/drivers/dma/idxd/dma.c
index c39e9483206a..1ea663215909 100644
--- a/drivers/dma/idxd/dma.c
+++ b/drivers/dma/idxd/dma.c
@@ -21,7 +21,8 @@ static inline struct idxd_wq *to_idxd_wq(struct dma_chan *c)
 }
 
 void idxd_dma_complete_txd(struct idxd_desc *desc,
-			   enum idxd_complete_type comp_type)
+			   enum idxd_complete_type comp_type,
+			   bool free_desc)
 {
 	struct dma_async_tx_descriptor *tx;
 	struct dmaengine_result res;
@@ -44,6 +45,9 @@ void idxd_dma_complete_txd(struct idxd_desc *desc,
 		tx->callback = NULL;
 		tx->callback_result = NULL;
 	}
+
+	if (free_desc)
+		idxd_free_desc(desc->wq, desc);
 }
 
 static void op_flag_setup(unsigned long flags, u32 *desc_flags)
@@ -153,8 +157,10 @@ static dma_cookie_t idxd_dma_tx_submit(struct dma_async_tx_descriptor *tx)
 	cookie = dma_cookie_assign(tx);
 
 	rc = idxd_submit_desc(wq, desc);
-	if (rc < 0)
+	if (rc < 0) {
+		idxd_free_desc(wq, desc);
 		return rc;
+	}
 
 	return cookie;
 }
diff --git a/drivers/dma/idxd/idxd.h b/drivers/dma/idxd/idxd.h
index 0cf8d3145870..3d600f8ee90b 100644
--- a/drivers/dma/idxd/idxd.h
+++ b/drivers/dma/idxd/idxd.h
@@ -579,7 +579,7 @@ int idxd_register_dma_channel(struct idxd_wq *wq);
 void idxd_unregister_dma_channel(struct idxd_wq *wq);
 void idxd_parse_completion_status(u8 status, enum dmaengine_tx_result *res);
 void idxd_dma_complete_txd(struct idxd_desc *desc,
-			   enum idxd_complete_type comp_type);
+			   enum idxd_complete_type comp_type, bool free_desc);
 
 /* cdev */
 int idxd_cdev_register(void);
@@ -603,10 +603,4 @@ static inline void perfmon_init(void) {}
 static inline void perfmon_exit(void) {}
 #endif
 
-static inline void complete_desc(struct idxd_desc *desc, enum idxd_complete_type reason)
-{
-	idxd_dma_complete_txd(desc, reason);
-	idxd_free_desc(desc->wq, desc);
-}
-
 #endif
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 7bf03f371ce1..4373b48cdc91 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -717,10 +717,8 @@ static void idxd_flush_pending_llist(struct idxd_irq_entry *ie)
 	if (!head)
 		return;
 
-	llist_for_each_entry_safe(desc, itr, head, llnode) {
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT);
-		idxd_free_desc(desc->wq, desc);
-	}
+	llist_for_each_entry_safe(desc, itr, head, llnode)
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 }
 
 static void idxd_flush_work_list(struct idxd_irq_entry *ie)
@@ -729,8 +727,7 @@ static void idxd_flush_work_list(struct idxd_irq_entry *ie)
 
 	list_for_each_entry_safe(desc, iter, &ie->work_list, list) {
 		list_del(&desc->list);
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT);
-		idxd_free_desc(desc->wq, desc);
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 	}
 }
 
diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 17f2f8a31b63..d9c4fc22536d 100644
--- a/drivers/dma/idxd/irq.c
+++ b/drivers/dma/idxd/irq.c
@@ -195,11 +195,11 @@ static void irq_process_pending_llist(struct idxd_irq_entry *irq_entry)
 			 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
 			 */
 			if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
-				complete_desc(desc, IDXD_COMPLETE_ABORT);
+				idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 				continue;
 			}
 
-			complete_desc(desc, IDXD_COMPLETE_NORMAL);
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL, true);
 		} else {
 			spin_lock(&irq_entry->list_lock);
 			list_add_tail(&desc->list,
@@ -238,11 +238,11 @@ static void irq_process_work_list(struct idxd_irq_entry *irq_entry)
 		 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
 		 */
 		if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
-			complete_desc(desc, IDXD_COMPLETE_ABORT);
+			idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
 			continue;
 		}
 
-		complete_desc(desc, IDXD_COMPLETE_NORMAL);
+		idxd_dma_complete_txd(desc, IDXD_COMPLETE_NORMAL, true);
 	}
 }
 
diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index de76fb4abac2..ea11809dbb32 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -129,7 +129,7 @@ static void llist_abort_desc(struct idxd_wq *wq, struct idxd_irq_entry *ie,
 	spin_unlock(&ie->list_lock);
 
 	if (found)
-		complete_desc(found, IDXD_COMPLETE_ABORT);
+		idxd_dma_complete_txd(found, IDXD_COMPLETE_ABORT, false);
 }
 
 int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
@@ -139,15 +139,11 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 	void __iomem *portal;
 	int rc;
 
-	if (idxd->state != IDXD_DEV_ENABLED) {
-		idxd_free_desc(wq, desc);
+	if (idxd->state != IDXD_DEV_ENABLED)
 		return -EIO;
-	}
 
-	if (!percpu_ref_tryget_live(&wq->wq_active)) {
-		idxd_free_desc(wq, desc);
+	if (!percpu_ref_tryget_live(&wq->wq_active))
 		return -ENXIO;
-	}
 
 	portal = idxd_wq_portal_addr(wq);
 
@@ -182,8 +178,6 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
 			/* abort operation frees the descriptor */
 			if (ie)
 				llist_abort_desc(wq, ie, desc);
-			else
-				idxd_free_desc(wq, desc);
 			return rc;
 		}
 	}