On Thu, 2013-10-03 at 21:11 -0700, Alexei Starovoitov wrote:
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index a6ac848..5d66cd9 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -25,15 +25,20 @@ struct sk_filter
> {
> atomic_t refcnt;
> unsigned int len; /* Number of filter blocks */
> + struct rcu_head rcu;
> unsigned int (*bpf_func)(const struct sk_buff *skb,
> const struct sock_filter *filter);
> - struct rcu_head rcu;
> + /* insns start right after bpf_func, so that sk_run_filter() fetches
> + * first insn from the same cache line that was used to call into
> + * sk_run_filter()
> + */
> struct sock_filter insns[0];
> };
>
> static inline unsigned int sk_filter_len(const struct sk_filter *fp)
> {
> - return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
> + return max(fp->len * sizeof(struct sock_filter),
> + sizeof(struct work_struct)) + sizeof(*fp);
> }
I would use for include/linux/filter.h this (untested) diff :
(Note the include <linux/workqueue.h>)
I also remove your comment about cache lines, since there is nothing
to align stuff on a cache line boundary.
diff --git a/include/linux/filter.h b/include/linux/filter.h
index a6ac848..281b05c 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -6,6 +6,7 @@
#include <linux/atomic.h>
#include <linux/compat.h>
+#include <linux/workqueue.h>
#include <uapi/linux/filter.h>
#ifdef CONFIG_COMPAT
@@ -25,15 +26,20 @@ struct sk_filter
{
atomic_t refcnt;
unsigned int len; /* Number of filter blocks */
+ struct rcu_head rcu;
unsigned int (*bpf_func)(const struct sk_buff *skb,
const struct sock_filter *filter);
- struct rcu_head rcu;
- struct sock_filter insns[0];
+ union {
+ struct work_struct work;
+ struct sock_filter insns[0];
+ };
};
-static inline unsigned int sk_filter_len(const struct sk_filter *fp)
+static inline unsigned int sk_filter_size(const struct sk_filter *fp,
+ unsigned int proglen)
{
- return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
+ return max(sizeof(*fp),
+ offsetof(struct sk_filter, insns[proglen]));
}
extern int sk_filter(struct sock *sk, struct sk_buff *skb);
This way, you can use sk_filter_size(fp, fprog->len)
instead of doing the max() games in sk_attach_filter() and
sk_unattached_filter_create()
Other than that, I think your patch is fine.
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