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FAILED: patch "[PATCH] dmaengine: idxd: fix descriptor flushing locking" failed to apply to 5.15-stable tree

PATCH [email protected] 1 participant 1 message Jan 24, 2022

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Stable branch dmaengine Intel IDXD driver
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The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 23a50c8035655c5a1d9b52c878b3ebf7b6b83eea Mon Sep 17 00:00:00 2001
From: Dave Jiang <[email protected]>
Date: Mon, 13 Dec 2021 11:51:29 -0700
Subject: [PATCH] dmaengine: idxd: fix descriptor flushing locking

The descriptor flushing for shutdown is not holding the irq_entry list lock. If there's ongoing interrupt completion handling, this can corrupt the list. Add locking to protect list walking. Also refactor the code so it's more compact.

Fixes 8f47d1a5e545 ("dmaengine: idxd: connect idxd to dmaengine subsystem")
Signed-off-by Dave Jiang <[email protected]>
Link https://lore.kernel.org/r/163942148935.2412839.18282664745572777280.stgit@djiang5-desk3.ch.intel.com open here
Signed-off-by Vinod Koul <[email protected]>
drivers/dma/idxd/init.c +15 -14
index 29c732a94027..03c735727f68 100644
@@ -689,26 +689,28 @@ static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	return rc;
 }
 
-static void idxd_flush_pending_llist(struct idxd_irq_entry *ie)
+static void idxd_flush_pending_descs(struct idxd_irq_entry *ie)
 {
 	struct idxd_desc *desc, *itr;
 	struct llist_node *head;
+	LIST_HEAD(flist);
+	enum idxd_complete_type ctype;
 
+	spin_lock(&ie->list_lock);
 	head = llist_del_all(&ie->pending_llist);
-	if (!head)
-		return;
-
-	llist_for_each_entry_safe(desc, itr, head, llnode)
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
-}
+	if (head) {
+		llist_for_each_entry_safe(desc, itr, head, llnode)
+			list_add_tail(&desc->list, &ie->work_list);
+	}
 
-static void idxd_flush_work_list(struct idxd_irq_entry *ie)
-{
-	struct idxd_desc *desc, *iter;
+	list_for_each_entry_safe(desc, itr, &ie->work_list, list)
+		list_move_tail(&desc->list, &flist);
+	spin_unlock(&ie->list_lock);
 
-	list_for_each_entry_safe(desc, iter, &ie->work_list, list) {
+	list_for_each_entry_safe(desc, itr, &flist, list) {
 		list_del(&desc->list);
-		idxd_dma_complete_txd(desc, IDXD_COMPLETE_ABORT, true);
+		ctype = desc->completion->status ? IDXD_COMPLETE_NORMAL : IDXD_COMPLETE_ABORT;
+		idxd_dma_complete_txd(desc, ctype, true);
 	}
 }
 

@@ -762,8 +764,7 @@ static void idxd_shutdown(struct pci_dev *pdev)
 		synchronize_irq(irq_entry->vector);
 		if (i == 0)
 			continue;
-		idxd_flush_pending_llist(irq_entry);
-		idxd_flush_work_list(irq_entry);
+		idxd_flush_pending_descs(irq_entry);
 	}
 	flush_workqueue(idxd->wq);
 }