Patch "mlxsw: spectrum: Fix refcount bug on span entries" has been added to the 4.8-stable tree

This is a note to let you know that I've just added the patch titled

mlxsw: spectrum: Fix refcount bug on span entries

to the 4.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
mlxsw-spectrum-fix-refcount-bug-on-span-entries.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Yotam Gigi <[email protected]>
Date: Fri, 11 Nov 2016 16:34:25 +0100
Subject: mlxsw: spectrum: Fix refcount bug on span entries

From: Yotam Gigi <[email protected]>

[ Upstream commit 2d644d4c7506646f9c4a2afceb7fd5f030bc0c9f ]

When binding port to a newly created span entry, its refcount is initialized to zero even though it has a bound port. That leads to unexpected behaviour when the user tries to delete that port from the span entry.

Fix this by initializing the reference count to 1.

Also add a warning to put function.

---
 drivers/net/ethernet/mellanox/mlxsw/spectrum.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

@@ -231,7 +231,7 @@ mlxsw_sp_span_entry_create(struct mlxsw_
 
 	span_entry->used = true;
 	span_entry->id = index;
-	span_entry->ref_count = 0;
+	span_entry->ref_count = 1;
 	span_entry->local_port = local_port;
 	return span_entry;
 }

@@ -268,6 +268,7 @@ struct mlxsw_sp_span_entry *mlxsw_sp_spa
 
 	span_entry = mlxsw_sp_span_entry_find(port);
 	if (span_entry) {
+		/* Already exists, just take a reference */
 		span_entry->ref_count++;
 		return span_entry;
 	}

@@ -278,6 +279,7 @@ struct mlxsw_sp_span_entry *mlxsw_sp_spa
 static int mlxsw_sp_span_entry_put(struct mlxsw_sp *mlxsw_sp,
 				   struct mlxsw_sp_span_entry *span_entry)
 {
+	WARN_ON(!span_entry->ref_count);
 	if (--span_entry->ref_count == 0)
 		mlxsw_sp_span_entry_destroy(mlxsw_sp, span_entry);
 	return 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.8/mlxsw-spectrum-fix-refcount-bug-on-span-entries.patch