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authorMaxime Ripard <maxime@cerno.tech>2021-04-26 14:03:09 +0200
committerMaxime Ripard <maxime@cerno.tech>2021-04-26 14:03:09 +0200
commit355b60296143a090039211c5f0e1463f84aab65a (patch)
treeb74d4ef2aea66252ea9cf77c847de6c6e72a02b7 /include/uapi/linux/bpf.h
parent91185d55b32e7e377f15fb46a62b216f8d3038d4 (diff)
parenta1a1ca70deb3ec600eeabb21de7f3f48aaae5695 (diff)
downloadlwn-355b60296143a090039211c5f0e1463f84aab65a.tar.gz
lwn-355b60296143a090039211c5f0e1463f84aab65a.zip
Merge drm/drm-next into drm-misc-next
Christian needs some patches from drm/next Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Diffstat (limited to 'include/uapi/linux/bpf.h')
-rw-r--r--include/uapi/linux/bpf.h16
1 files changed, 11 insertions, 5 deletions
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 79c893310492..4ba4ef0ff63a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -3850,7 +3850,7 @@ union bpf_attr {
*
* long bpf_check_mtu(void *ctx, u32 ifindex, u32 *mtu_len, s32 len_diff, u64 flags)
* Description
- * Check ctx packet size against exceeding MTU of net device (based
+ * Check packet size against exceeding MTU of net device (based
* on *ifindex*). This helper will likely be used in combination
* with helpers that adjust/change the packet size.
*
@@ -3867,6 +3867,14 @@ union bpf_attr {
* against the current net device. This is practical if this isn't
* used prior to redirect.
*
+ * On input *mtu_len* must be a valid pointer, else verifier will
+ * reject BPF program. If the value *mtu_len* is initialized to
+ * zero then the ctx packet size is use. When value *mtu_len* is
+ * provided as input this specify the L3 length that the MTU check
+ * is done against. Remember XDP and TC length operate at L2, but
+ * this value is L3 as this correlate to MTU and IP-header tot_len
+ * values which are L3 (similar behavior as bpf_fib_lookup).
+ *
* The Linux kernel route table can configure MTUs on a more
* specific per route level, which is not provided by this helper.
* For route level MTU checks use the **bpf_fib_lookup**\ ()
@@ -3891,11 +3899,9 @@ union bpf_attr {
*
* On return *mtu_len* pointer contains the MTU value of the net
* device. Remember the net device configured MTU is the L3 size,
- * which is returned here and XDP and TX length operate at L2.
+ * which is returned here and XDP and TC length operate at L2.
* Helper take this into account for you, but remember when using
- * MTU value in your BPF-code. On input *mtu_len* must be a valid
- * pointer and be initialized (to zero), else verifier will reject
- * BPF program.
+ * MTU value in your BPF-code.
*
* Return
* * 0 on success, and populate MTU value in *mtu_len* pointer.