[PATCHv2 net-next] net: filter: move load_pointer() into filter.h

From: Zi Shen Lim
Date: Thu Jul 03 2014 - 10:57:13 EST


load_pointer() is already a static inline function.
Let's move it into filter.h so BPF JIT implementations can reuse this
function.

Since we're exporting this function, let's also rename it to
bpf_load_pointer() for clarity.

Signed-off-by: Zi Shen Lim <zlim.lnx@xxxxxxxxx>
---
v1->v2:
* Renamed to more specific name of bpf_load_pointer(), as suggested
by Daniel.

This patch is based on discussion with Alexei in the context of
reusing load_pointer for upcoming arm64 BPF JIT compiler. [1]
Compile tested on x86_64 and arm64.

[1] https://lkml.org/lkml/2014/7/3/14

include/linux/filter.h | 13 +++++++++++++
net/core/filter.c | 15 +++------------
2 files changed, 16 insertions(+), 12 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index a7e3c48..b885dcb 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/skbuff.h>
#include <linux/workqueue.h>
#include <uapi/linux/filter.h>

@@ -406,6 +407,18 @@ static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
}
}

+void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
+ int k, unsigned int size);
+
+static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
+ unsigned int size, void *buffer)
+{
+ if (k >= 0)
+ return skb_header_pointer(skb, k, size, buffer);
+
+ return bpf_internal_load_pointer_neg_helper(skb, k, size);
+}
+
#ifdef CONFIG_BPF_JIT
#include <stdarg.h>
#include <linux/linkage.h>
diff --git a/net/core/filter.c b/net/core/filter.c
index 1dbf646..87af1e3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -84,15 +84,6 @@ void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, uns
return NULL;
}

-static inline void *load_pointer(const struct sk_buff *skb, int k,
- unsigned int size, void *buffer)
-{
- if (k >= 0)
- return skb_header_pointer(skb, k, size, buffer);
-
- return bpf_internal_load_pointer_neg_helper(skb, k, size);
-}
-
/**
* sk_filter - run a packet through a socket filter
* @sk: sock associated with &sk_buff
@@ -537,7 +528,7 @@ load_word:
* BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
*/

- ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
+ ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = get_unaligned_be32(ptr);
CONT;
@@ -547,7 +538,7 @@ load_word:
LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
off = IMM;
load_half:
- ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
+ ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = get_unaligned_be16(ptr);
CONT;
@@ -557,7 +548,7 @@ load_half:
LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
off = IMM;
load_byte:
- ptr = load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
+ ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
if (likely(ptr != NULL)) {
BPF_R0 = *(u8 *)ptr;
CONT;
--
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/