Re: [PATCH 1/2] ALSA: ctxfi: Deletion of an unnecessary check before the function call "kfree"

Joe Perches
2014-12-02T21:07:51Z

On Tue, 2014-12-02 at 21:55 +0100, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Tue, 2 Dec 2014 20:00:33 +0100
>
> The kfree() function performs also input parameter validation.
> Thus the test around the call is not needed.
>
> This issue was detected by using the Coccinelle software.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
> sound/pci/ctxfi/ctdaio.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/pci/ctxfi/ctdaio.c b/sound/pci/ctxfi/ctdaio.c
> index c1c3f88..1712332 100644
> --- a/sound/pci/ctxfi/ctdaio.c
> +++ b/sound/pci/ctxfi/ctdaio.c
> @@ -577,7 +577,7 @@ static int get_daio_rsc(struct daio_mgr *mgr,
> error:
> if (dao)
> kfree(dao);
> - else if (dai)
> + else
> kfree(dai);
>
> spin_lock_irqsave(&mgr->mgr_lock, flags);

I think this not nice and would prefer something like:

---
sound/pci/ctxfi/ctdaio.c | 30 +++++++++++++-----------------
1 file changed, 13 insertions(+), 17 deletions(-)

diff --git a/sound/pci/ctxfi/ctdaio.c b/sound/pci/ctxfi/ctdaio.c
index c1c3f88..9b87dd2 100644
--- a/sound/pci/ctxfi/ctdaio.c
+++ b/sound/pci/ctxfi/ctdaio.c
@@ -528,8 +528,6 @@ static int get_daio_rsc(struct daio_mgr *mgr,
struct daio **rdaio)
{
int err;
- struct dai *dai = NULL;
- struct dao *dao = NULL;
unsigned long flags;

*rdaio = NULL;
@@ -544,27 +542,30 @@ static int get_daio_rsc(struct daio_mgr *mgr,
return err;
}

+ err = -ENOMEM;
/* Allocate mem for daio resource */
if (desc->type <= DAIO_OUT_MAX) {
- dao = kzalloc(sizeof(*dao), GFP_KERNEL);
- if (!dao) {
- err = -ENOMEM;
+ struct dao *dao = kzalloc(sizeof(*dao), GFP_KERNEL);
+ if (!dao)
goto error;
- }
+
err = dao_rsc_init(dao, desc, mgr);
- if (err)
+ if (err) {
+ kfree(dao);
goto error;
+ }

*rdaio = &dao->daio;
} else {
- dai = kzalloc(sizeof(*dai), GFP_KERNEL);
- if (!dai) {
- err = -ENOMEM;
+ struct dai *dai = kzalloc(sizeof(*dai), GFP_KERNEL);
+ if (!dai)
goto error;
- }
+
err = dai_rsc_init(dai, desc, mgr);
- if (err)
+ if (err) {
+ kfree(dai);
goto error;
+ }

*rdaio = &dai->daio;
}
@@ -575,11 +576,6 @@ static int get_daio_rsc(struct daio_mgr *mgr,
return 0;

error:
- if (dao)
- kfree(dao);
- else if (dai)
- kfree(dai);
-
spin_lock_irqsave(&mgr->mgr_lock, flags);
daio_mgr_put_rsc(&mgr->mgr, desc->type);
spin_unlock_irqrestore(&mgr->mgr_lock, flags);