Re: [PATCH 2/6] test_bpf: allow tests to specify an skb fragment.

From: Daniel Borkmann
Date: Mon Aug 03 2015 - 11:29:48 EST


On 08/03/2015 04:02 PM, Nicolas Schichan wrote:
This introduce a new test->aux flag (FLAG_SKB_FRAG) to tell the
populate_skb() function to add a fragment to the test skb containing
the data specified in test->frag_data).

Signed-off-by: Nicolas Schichan <nschichan@xxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxxxx>

Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>

I'm good with this change here, just a comment below in general.

enum {
CLASSIC = BIT(6), /* Old BPF instructions only. */
@@ -81,6 +83,7 @@ struct bpf_test {
__u32 result;
} test[MAX_SUBTESTS];
int (*fill_helper)(struct bpf_test *self);
+ __u8 frag_data[MAX_DATA];
};

We now have 286 tests, which is awesome!

Perhaps, we need to start thinking of a better test description method
soonish as the test_bpf.ko module grew to ~1.6M, i.e. whenever we add
to struct bpf_test, it adds memory overhead upon all test cases.

/* Large test cases need separate allocation and fill handler. */
@@ -4525,6 +4528,10 @@ static struct sk_buff *populate_skb(char *buf, int size)

static void *generate_test_data(struct bpf_test *test, int sub)
{
+ struct sk_buff *skb;
+ struct page *page;
+ void *ptr;
+
if (test->aux & FLAG_NO_DATA)
return NULL;

@@ -4532,7 +4539,36 @@ static void *generate_test_data(struct bpf_test *test, int sub)
* subtests generate skbs of different sizes based on
* the same data.
*/
- return populate_skb(test->data, test->test[sub].data_size);
+ skb = populate_skb(test->data, test->test[sub].data_size);
+ if (!skb)
+ return NULL;
+
+ if (test->aux & FLAG_SKB_FRAG) {

Really minor nit: declaration of page, ptr could have been only in this block.
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