May 27 2014

display7seg: Introduce the use of the managed version of kzalloc 

Author: Himangi Saraogi <himangi774@gmail.com>

This patch moves data allocated using kzalloc to managed data allocated
using devm_kzalloc and cleans now unnecessary kfrees in probe and remove
functions. The header file is added to make the devm function explicitly
available.

The following Coccinelle semantic patch was used for making a part of
the change:

@platform@
identifier p, probefn, removefn;
@@
struct platform_driver p = {
  .probe = probefn,
  .remove = removefn,
};

@prb@
identifier platform.probefn, pdev;
expression e, e1, e2;
@@
probefn(struct platform_device *pdev, ...) {
  <+...
- e = kzalloc(e1, e2)
+ e = devm_kzalloc(&pdev->dev, e1, e2)
  ...
?-kfree(e);
  ...+>
}

@rem depends on prb@
identifier platform.removefn;
expression e;
@@
removefn(...) {
  <...
- kfree(e);
  ...>
}

Signed-off-by: Himangi Saraogi 
Acked-by: Julia Lawall 
Acked-by: Sam Ravnborg 
Signed-off-by: David S. Miller 

---
 drivers/sbus/char/display7seg.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
 
diff --git a/drivers/sbus/char/display7seg.c b/drivers/sbus/char/display7seg.c
index 7c71e7b..b48899c 100644
--- a/drivers/sbus/char/display7seg.c
+++ b/drivers/sbus/char/display7seg.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
  */
 
+#include <linux/device.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/fs.h>
@@ -180,7 +181,7 @@ static int d7s_probe(struct platform_device *op)
 	if (d7s_device)
 		goto out;
 
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	p = devm_kzalloc(&op->dev, sizeof(*p), GFP_KERNEL);
 	err = -ENOMEM;
 	if (!p)
 		goto out;
@@ -231,7 +232,6 @@ out_iounmap:
 	of_iounmap(&op->resource[0], p->regs, sizeof(u8));
 
 out_free:
-	kfree(p);
 	goto out;
 }
 
@@ -251,7 +251,6 @@ static int d7s_remove(struct platform_device *op)
 
 	misc_deregister(&d7s_miscdev);
 	of_iounmap(&op->resource[0], p->regs, sizeof(u8));
-	kfree(p);
 
 	return 0;
 }

qlambert