Re: [Outreachy kernel] [PATCH] Staging: irda: Use !x instead of NULL comparison

From: Julia Lawall
Date: Sat Sep 16 2017 - 03:14:29 EST




On Sat, 16 Sep 2017, Srishti Sharma wrote:

> Test for NULL as !x where functions that return NULL on failure
> are used. Done using the following semantic patch by coccinelle.
>
> @ is_null @
> expression E;
> statement S;
> @@
>
> E = (\(kmalloc\|devm_kzalloc\|kmalloc_array\|devm_ioremap\|
> usb_alloc_urb\|alloc_netdev\|dev_alloc_skb\)(...));
>
> (
> if(!E)
> S
> |
> -if(E==NULL)
> +if(!E)
> S
> )
>
> Signed-off-by: Srishti Sharma <srishtishar@xxxxxxxxx>

Acked-by: Julia Lawall <julia.lawall@xxxxxxx>


> ---
> drivers/staging/irda/net/discovery.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/irda/net/discovery.c b/drivers/staging/irda/net/discovery.c
> index 364d70a..1e54954 100644
> --- a/drivers/staging/irda/net/discovery.c
> +++ b/drivers/staging/irda/net/discovery.c
> @@ -179,7 +179,7 @@ void irlmp_expire_discoveries(hashbin_t *log, __u32 saddr, int force)
> /* Create the client specific buffer */
> n = HASHBIN_GET_SIZE(log);
> buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
> - if (buffer == NULL) {
> + if (!buffer) {
> spin_unlock_irqrestore(&log->hb_spinlock, flags);
> return;
> }
> @@ -291,7 +291,7 @@ struct irda_device_info *irlmp_copy_discoveries(hashbin_t *log, int *pn,
> /* Create the client specific buffer */
> n = HASHBIN_GET_SIZE(log);
> buffer = kmalloc(n * sizeof(struct irda_device_info), GFP_ATOMIC);
> - if (buffer == NULL) {
> + if (!buffer) {
> spin_unlock_irqrestore(&log->hb_spinlock, flags);
> return NULL;
> }
> --
> 2.7.4
>
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