[PATCH 1/5] staging: comedi: serial2002: Combine four kcalloc() calls into one in serial2002_setup_subdevs()

[SF Markus Elfring]

From: Markus Elfring <elfr...@users.sourceforge.net>
Date: Thu, 8 Dec 2016 07:37:29 +0100

The function "kcalloc" was called in three cases by the function
"serial2002_setup_subdevs" without checking immediately if it failed.
This issue was detected by using the Coccinelle software.

* Perform the desired memory allocation (and release at the end) by a single
  function call instead.

* Adjust a jump target so that a redundant check is avoided.

Fixes: 623a73926c7012e3bb132e225621890207f5c611 ("staging: comedi: serial2002: 
split up serial_2002_open()")

Signed-off-by: Markus Elfring <elfr...@users.sourceforge.net>
---
 drivers/staging/comedi/drivers/serial2002.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/staging/comedi/drivers/serial2002.c 
b/drivers/staging/comedi/drivers/serial2002.c
index 0d33e520f635..9542f4f8afe0 100644
--- a/drivers/staging/comedi/drivers/serial2002.c
+++ b/drivers/staging/comedi/drivers/serial2002.c
@@ -392,6 +392,7 @@ static int serial2002_setup_subdevice(struct 
comedi_subdevice *s,
 static int serial2002_setup_subdevs(struct comedi_device *dev)
 {
        struct serial2002_private *devpriv = dev->private;
+       struct config_t *array;
        struct config_t *di_cfg;
        struct config_t *do_cfg;
        struct config_t *ai_cfg;
@@ -402,15 +403,17 @@ static int serial2002_setup_subdevs(struct comedi_device 
*dev)
        int i;
 
        /* Allocate the temporary structs to hold the configuration data */
-       di_cfg = kcalloc(32, sizeof(*cfg), GFP_KERNEL);
-       do_cfg = kcalloc(32, sizeof(*cfg), GFP_KERNEL);
-       ai_cfg = kcalloc(32, sizeof(*cfg), GFP_KERNEL);
-       ao_cfg = kcalloc(32, sizeof(*cfg), GFP_KERNEL);
-       if (!di_cfg || !do_cfg || !ai_cfg || !ao_cfg) {
+       array = kcalloc(4 * 32, sizeof(*cfg), GFP_KERNEL);
+       if (!array) {
                result = -ENOMEM;
-               goto err_alloc_configs;
+               goto check_tty;
        }
 
+       di_cfg = array;
+       do_cfg = array + 1 * 32;
+       ai_cfg = array + 2 * 32;
+       ao_cfg = array + 3 * 32;
+
        /* Read the configuration from the connected device */
        serial2002_tty_setspeed(devpriv->tty, devpriv->speed);
        serial2002_poll_channel(devpriv->tty, 31);
@@ -534,13 +537,10 @@ static int serial2002_setup_subdevs(struct comedi_device 
*dev)
                }
        }
 
-err_alloc_configs:
-       kfree(di_cfg);
-       kfree(do_cfg);
-       kfree(ai_cfg);
-       kfree(ao_cfg);
+       kfree(array);
 
        if (result) {
+check_tty:
                if (devpriv->tty) {
                        filp_close(devpriv->tty, NULL);
                        devpriv->tty = NULL;
-- 
2.11.0