ASoC: rsnd: fix usrcnt decrementing bug

Field usrcnt is unsigned so it cannot be lesser than zero.
The patch fixes the check, moves it to the beginning of the function
and changes return value to -EIO in case of usercnt error.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2038576

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 14 insertions, 13 deletions

diff --git a/sound/soc/sh/rcar/ssi.c b/sound/soc/sh/rcar/ssi.c
index 7db05fdfb656..7ee89da4dd5f 100644
--- a/sound/soc/sh/rcar/ssi.c
+++ b/sound/soc/sh/rcar/ssi.c
@@ -403,29 +403,30 @@ static int rsnd_ssi_quit(struct rsnd_mod *mod,
         struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
         struct device *dev = rsnd_priv_to_dev(priv);
 
-        if (rsnd_ssi_is_parent(mod, io))
-                goto rsnd_ssi_quit_end;
+        if (!ssi->usrcnt) {
+                dev_err(dev, "%s[%d] usrcnt error\n",
+                        rsnd_mod_name(mod), rsnd_mod_id(mod));
+                return -EIO;
+        }
 
-        if (ssi->err > 0)
-                dev_warn(dev, "%s[%d] under/over flow err = %d\n",
-                         rsnd_mod_name(mod), rsnd_mod_id(mod), ssi->err);
+        if (!rsnd_ssi_is_parent(mod, io)) {
+                if (ssi->err > 0)
+                        dev_warn(dev, "%s[%d] under/over flow err = %d\n",
+                                 rsnd_mod_name(mod), rsnd_mod_id(mod),
+                                 ssi->err);
 
-        ssi->cr_own     = 0;
-        ssi->err        = 0;
+                ssi->cr_own     = 0;
+                ssi->err        = 0;
 
-        rsnd_ssi_irq_disable(mod);
+                rsnd_ssi_irq_disable(mod);
+        }
 
-rsnd_ssi_quit_end:
         rsnd_ssi_master_clk_stop(ssi, io);
 
         rsnd_mod_power_off(mod);
 
         ssi->usrcnt--;
 
-        if (ssi->usrcnt < 0)
-                dev_err(dev, "%s[%d] usrcnt error\n",
-                        rsnd_mod_name(mod), rsnd_mod_id(mod));
-
         return 0;
 }