Re: [alsa-devel] [PATCH 3/4] sound/soc/mxs/mxs-saif.c: add missing kfree

21 Aug 2011

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-----Original Message-----
From: Julia Lawall [mailto:julia@diku.dk]
Sent: Saturday, August 20, 2011 11:19 PM
To: Wolfram Sang
Cc: Liam Girdwood; kernel-janitors@vger.kernel.org; Mark Brown; Jaroslav
Kysela; Takashi Iwai; Dong Aisheng-B29396; alsa-devel@alsa-project.org;
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] sound/soc/mxs/mxs-saif.c: add missing kfree
From: Julia Lawall julia@diku.dk
Move the test on pdev->id before the kzalloc to avoid requiring kfree
when the test fails.  This fix was suggested by Wolfram Sang.
A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)
// <smpl>
@@
identifier x;
expression E1!=0,E2,E3,E4;
statement S;
iterator I;
@@
(
if (...) { ... when != kfree(x)
               when != x = E3
               when != E3 = x

return ...;

}
... when != x = E2
    when != I(...,x,...) S
if (...) { ... when != x = E4
 kfree(x); ... return ...; }
)
// </smpl>
Signed-off-by: Julia Lawall julia@diku.dk

diff --git a/sound/soc/mxs/mxs-saif.c b/sound/soc/mxs/mxs-saif.c index
0b3adae..e9a90e4 100644
--- a/sound/soc/mxs/mxs-saif.c
+++ b/sound/soc/mxs/mxs-saif.c
@@ -519,12 +519,11 @@ static int mxs_saif_probe(struct platform_device
*pdev)
   struct mxs_saif *saif;
   int ret = 0;

if (pdev->id >= ARRAY_SIZE(mxs_saif))
return -EINVAL;

saif = kzalloc(sizeof(*saif), GFP_KERNEL);
if (!saif)
return -ENOMEM;



if (pdev->id >= ARRAY_SIZE(mxs_saif))

return -EINVAL;

mxs_saif[pdev->id] = saif;
saif->clk = clk_get(&pdev->dev, NULL);


Thanks for the finding, Julia.
It's ok to me.
BTW I guess you may need to resend a new version patch instead of following it
in this mail thread. :)
If yes, one minus thing, add one blank line below the line of 'return -ENOMEM'
may look more comfortable.
Regards
Dong Aisheng

    