[PATCH 2/7] drivers/staging: Return -ENOMEM on memory allocation failure

[Julia Lawall <julia@diku.dk>]

From: Julia Lawall <julia@diku.dk>

Each of these functions defines a variable err and a variable retval.  err
is always 0 and is returned in the error case.  At one point near the end
of the function, retval is initialized to an error code.  For each
function, the patch drops err, stores -ENOMEM in retval in two cases where
memory allocation fails, and changes the return value in the error case
from err to retval.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@@
expression ret;
expression x,e1,e2,e3;
@@

ret = 0
... when != ret = e1
*x = \(kmalloc\|kcalloc\|kzalloc\)(...)
... when != ret = e2
if (x = NULL) { ... when != ret = e3
  return ret;
}
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>

---
 drivers/staging/cx25821/cx25821-audio-upstream.c     |   11 +++++++----
 drivers/staging/cx25821/cx25821-video-upstream-ch2.c |   11 +++++++----
 drivers/staging/cx25821/cx25821-video-upstream.c     |   11 +++++++----
 3 files changed, 21 insertions(+), 12 deletions(-)

diff -u -p a/drivers/staging/cx25821/cx25821-audio-upstream.c b/drivers/staging/cx25821/cx25821-audio-upstream.c
--- a/drivers/staging/cx25821/cx25821-audio-upstream.c
+++ b/drivers/staging/cx25821/cx25821-audio-upstream.c
@@ -723,7 +723,6 @@ int cx25821_audio_upstream_init(struct c
 {
 	struct sram_channel *sram_ch;
 	int retval = 0;
-	int err = 0;
 	int str_length = 0;
 
 	if (dev->_audio_is_running) {
@@ -756,8 +755,10 @@ int cx25821_audio_upstream_init(struct c
 		str_length = strlen(dev->input_audiofilename);
 		dev->_audiofilename = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_audiofilename)
+		if (!dev->_audiofilename) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_audiofilename, dev->input_audiofilename,
 		       str_length + 1);
@@ -770,8 +771,10 @@ int cx25821_audio_upstream_init(struct c
 		str_length = strlen(_defaultAudioName);
 		dev->_audiofilename = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_audiofilename)
+		if (!dev->_audiofilename) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_audiofilename, _defaultAudioName, str_length + 1);
 	}
@@ -802,5 +805,5 @@ int cx25821_audio_upstream_init(struct c
 error:
 	cx25821_dev_unregister(dev);
 
-	return err;
+	return retval;
 }
diff -u -p a/drivers/staging/cx25821/cx25821-video-upstream-ch2.c b/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
--- a/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
+++ b/drivers/staging/cx25821/cx25821-video-upstream-ch2.c
@@ -747,7 +747,6 @@ int cx25821_vidupstream_init_ch2(struct 
 	struct sram_channel *sram_ch;
 	u32 tmp;
 	int retval = 0;
-	int err = 0;
 	int data_frame_size = 0;
 	int risc_buffer_size = 0;
 	int str_length = 0;
@@ -792,8 +791,10 @@ int cx25821_vidupstream_init_ch2(struct 
 		str_length = strlen(dev->input_filename_ch2);
 		dev->_filename_ch2 = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_filename_ch2)
+		if (!dev->_filename_ch2) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_filename_ch2, dev->input_filename_ch2,
 		       str_length + 1);
@@ -801,8 +802,10 @@ int cx25821_vidupstream_init_ch2(struct 
 		str_length = strlen(dev->_defaultname_ch2);
 		dev->_filename_ch2 = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_filename_ch2)
+		if (!dev->_filename_ch2) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_filename_ch2, dev->_defaultname_ch2,
 		       str_length + 1);
@@ -851,5 +854,5 @@ int cx25821_vidupstream_init_ch2(struct 
       error:
 	cx25821_dev_unregister(dev);
 
-	return err;
+	return retval;
 }
diff -u -p a/drivers/staging/cx25821/cx25821-video-upstream.c b/drivers/staging/cx25821/cx25821-video-upstream.c
--- a/drivers/staging/cx25821/cx25821-video-upstream.c
+++ b/drivers/staging/cx25821/cx25821-video-upstream.c
@@ -800,7 +800,6 @@ int cx25821_vidupstream_init_ch1(struct 
 	struct sram_channel *sram_ch;
 	u32 tmp;
 	int retval = 0;
-	int err = 0;
 	int data_frame_size = 0;
 	int risc_buffer_size = 0;
 	int str_length = 0;
@@ -844,16 +843,20 @@ int cx25821_vidupstream_init_ch1(struct 
 		str_length = strlen(dev->input_filename);
 		dev->_filename = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_filename)
+		if (!dev->_filename) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_filename, dev->input_filename, str_length + 1);
 	} else {
 		str_length = strlen(dev->_defaultname);
 		dev->_filename = kmalloc(str_length + 1, GFP_KERNEL);
 
-		if (!dev->_filename)
+		if (!dev->_filename) {
+			retval = -ENOMEM;
 			goto error;
+		}
 
 		memcpy(dev->_filename, dev->_defaultname, str_length + 1);
 	}
@@ -908,5 +911,5 @@ int cx25821_vidupstream_init_ch1(struct 
 error:
 	cx25821_dev_unregister(dev);
 
-	return err;
+	return retval;
 }