Re: [PATCH 3/8] drivers/pcmcia: remove unnecessary kzalloc

walter harms
2009-11-21T12:45:09Z

Julia Lawall schrieb:
> From: Julia Lawall <julia@diku.dk>
>
> The result of calling kzalloc is never used or freed.
>
> The semantic match that finds this problem is as follows:
> (http://www.emn.fr/x-info/coccinelle/)
>
> // <smpl>
> @r exists@
> local idexpression x;
> statement S;
> expression E;
> identifier f,f1,l;
> position p1,p2;
> expression *ptr != NULL;
> @@
>
> x@p1 = \(kmalloc\|kzalloc\|kcalloc\)(...);
> ...
> if (x == NULL) S
> <... when != x
> when != if (...) { <+...x...+> }
> (
> x->f1 = E
> |
> (x->f1 == NULL || ...)
> |
> f(...,x->f1,...)
> )
> ...>
> (
> return \(0\|<+...x...+>\|ptr\);
> |
> return@p2 ...;
> )
>
> @script:python@
> p1 << r.p1;
> p2 << r.p2;
> @@
>
> print "* file: %s kmalloc %s return %s" % (p1[0].file,p1[0].line,p2[0].line)
> // </smpl>
>
> Signed-off-by: Julia Lawall <julia@diku.dk>
> ---
> drivers/pcmcia/sa1111_generic.c | 4 ----
> 1 files changed, 0 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pcmcia/sa1111_generic.c b/drivers/pcmcia/sa1111_generic.c
> index deb5036..de6bc33 100644
> --- a/drivers/pcmcia/sa1111_generic.c
> +++ b/drivers/pcmcia/sa1111_generic.c
> @@ -127,10 +127,6 @@ int sa1111_pcmcia_add(struct sa1111_dev *dev, struct pcmcia_low_level *ops,
> ops->socket_state = sa1111_pcmcia_socket_state;
> ops->socket_suspend = sa1111_pcmcia_socket_suspend;
>
> - s = kzalloc(sizeof(*s) * ops->nr, GFP_KERNEL);
> - if (!s)
> - return -ENODEV;
> -
> for (i = 0; i < ops->nr; i++) {
> s = kzalloc(sizeof(*s), GFP_KERNEL);
> if (!s)

mmmh, perhaps the original idea was to have an array
and then he moved to a linked list ?

I thing the array idea is better (1. it fails on low mem propperly, 2. no need free()
3. less zmalloc stuff) but requieres that pcmcia_remove()
will release that array propperly

the bug is strange,

just my 2 cents,
re,
wh