[PATCH 4.19 021/114] stm class: Fix channel free in stm output free path

[Greg Kroah-Hartman]

From: Tingwei Zhang <tingwei@xxxxxxxxxxxxxx>

commit ee496da4c3915de3232b5f5cd20e21ae3e46fe8d upstream.

Number of free masters is not set correctly in stm
free path. Fix this by properly adding the number
of output channels before setting them to 0 in
stm_output_disclaim().

Currently it is equivalent to doing nothing since
master->nr_free is incremented by 0.

Fixes: 7bd1d4093c2f ("stm class: Introduce an abstraction for System Trace Module devices")
Signed-off-by: Tingwei Zhang <tingwei@xxxxxxxxxxxxxx>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.4
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/hwtracing/stm/core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -218,8 +218,8 @@ stm_output_disclaim(struct stm_device *s
 	bitmap_release_region(&master->chan_map[0], output->channel,
 			      ilog2(output->nr_chans));
 
-	output->nr_chans = 0;
 	master->nr_free += output->nr_chans;
+	output->nr_chans = 0;
 }
 
 /*