On Wed, 2017-06-14 at 22:17 +0200, Johannes Berg wrote:
> From: Johannes Berg <johannes.b...@intel.com>
>
> It's nicer to return void, since then there's no need to
> cast to any structures. Currently none of the users have
> a cast, but a number of future conversions do.
>
> Signed-off-by: Johannes Berg <johannes.b...@intel.com>
> ---
> include/linux/skbuff.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 1151b50892d1..01ea64d0783a 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -1904,9 +1904,9 @@ static inline unsigned char *__skb_put(struct sk_buff
> *skb, unsigned int len)
> return tmp;
> }
>
> -static inline unsigned char *skb_put_zero(struct sk_buff *skb, unsigned int
> len)
> +static inline void *skb_put_zero(struct sk_buff *skb, unsigned int len)
> {
> - unsigned char *tmp = skb_put(skb, len);
> + void *tmp = skb_put(skb, len);
>
> memset(tmp, 0, len);
Given you are adding a lot of these, it might be better
to add an exported function that duplicates most of
skb_put with a memset at the end.
That would probably create a smaller kernel and might
be a bit faster.
Perhaps:
---
include/linux/skbuff.h | 10 +---------
net/core/skbuff.c | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+), 9 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 78213b3f9552..f725cbe30c9c 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1895,6 +1895,7 @@ static inline void skb_set_tail_pointer(struct sk_buff
*skb, const int offset)
*/
unsigned char *pskb_put(struct sk_buff *skb, struct sk_buff *tail, int len);
unsigned char *skb_put(struct sk_buff *skb, unsigned int len);
+void *skb_put_zero(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_put(struct sk_buff *skb, unsigned int len)
{
unsigned char *tmp = skb_tail_pointer(skb);
@@ -1904,15 +1905,6 @@ static inline unsigned char *__skb_put(struct sk_buff
*skb, unsigned int len)
return tmp;
}
-static inline unsigned char *skb_put_zero(struct sk_buff *skb, unsigned int
len)
-{
- unsigned char *tmp = skb_put(skb, len);
-
- memset(tmp, 0, len);
-
- return tmp;
-}
-
unsigned char *skb_push(struct sk_buff *skb, unsigned int len);
static inline unsigned char *__skb_push(struct sk_buff *skb, unsigned int len)
{
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 304602784c3b..e70aa414b139 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1454,6 +1454,28 @@ unsigned char *skb_put(struct sk_buff *skb, unsigned int
len)
EXPORT_SYMBOL(skb_put);
/**
+ * skb_put_zero - add zeroed data to a buffer
+ * @skb: buffer to use
+ * @len: amount of zeroed data to add
+ *
+ * This function extends the used data area of the buffer. If this would
+ * exceed the total buffer size the kernel will panic. A pointer to the
+ * first byte of the extra data is returned.
+ */
+void *skb_put_zero(struct sk_buff *skb, unsigned int len)
+{
+ unsigned char *tmp = skb_tail_pointer(skb);
+
+ SKB_LINEAR_ASSERT(skb);
+ skb->tail += len;
+ skb->len += len;
+ if (unlikely(skb->tail > skb->end))
+ skb_over_panic(skb, len, __builtin_return_address(0));
+ return memset(tmp, 0, len);
+}
+EXPORT_SYMBOL(skb_put_zero);
+
+/**
* skb_push - add data to the start of a buffer
* @skb: buffer to use
* @len: amount of data to add
