On 6/27/22 18:24, Loftus, Ciara wrote:
On 6/27/22 17:17, Loftus, Ciara wrote:
On 6/24/22 13:23, Ciara Loftus wrote:
libbpf v0.8.0 deprecates the bpf_get_link_xdp_id and
bpf_set_link_xdp_fd
functions. Use meson to detect if libbpf >= v0.7.0 is linked and if so, use
the recommended replacement functions bpf_xdp_query_id,
bpf_xdp_attach
and bpf_xdp_detach which are available to use since libbpf v0.7.0.
Also prevent linking with libbpf versions > v0.8.0.
Signed-off-by: Ciara Loftus <ciara.lof...@intel.com>
---
doc/guides/nics/af_xdp.rst | 3 ++-
drivers/net/af_xdp/compat.h | 36
++++++++++++++++++++++++++++-
drivers/net/af_xdp/meson.build | 7 ++----
drivers/net/af_xdp/rte_eth_af_xdp.c | 19 +++------------
4 files changed, 42 insertions(+), 23 deletions(-)
Don't we need to mention these changes in release notes?
diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index 56681c8365..9edb48df67 100644
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -43,7 +43,8 @@ Prerequisites
This is a Linux-specific PMD, thus the following prerequisites apply:
* A Linux Kernel (version > v4.18) with XDP sockets configuration
enabled;
-* Both libxdp >=v1.2.2 and libbpf libraries installed, or, libbpf <=v0.6.0
+* Both libxdp >=v1.2.2 and libbpf <=v0.8.0 libraries installed, or, libbpf
+ <=v0.6.0.
* If using libxdp, it requires an environment variable called
LIBXDP_OBJECT_PATH to be set to the location of where libxdp
placed its
bpf
object files. This is usually in /usr/local/lib/bpf or
/usr/local/lib64/bpf.
diff --git a/drivers/net/af_xdp/compat.h
b/drivers/net/af_xdp/compat.h
index 28ea64aeaa..8f4ac8b5ea 100644
--- a/drivers/net/af_xdp/compat.h
+++ b/drivers/net/af_xdp/compat.h
@@ -60,7 +60,7 @@ tx_syscall_needed(struct xsk_ring_prod *q
__rte_unused)
}
#endif
-#ifdef RTE_NET_AF_XDP_LIBBPF_OBJ_OPEN
+#ifdef RTE_NET_AF_XDP_LIBBPF_V070
Typically version-based checks are considered as bad. Isn't it
better use feature-based checks/defines?
Hi Andrew,
Thank you for the feedback. Is the feature-based checking something that
we can push to the next release?
We are already using the pkg-config version-check method for other
libraries/features in the meson.build file:
* libxdp >= v1.2.2 # earliest compatible libxdp release
* libbpf >= v0.7.0 # bpf_object__* functions
* libbpf >= v0.2.0 # shared umem feature
If we change to your suggested method I think we should change them all
in one patch. IMO it's probably too close to the release to change them all
right now. What do you think?
Thanks,
Ciara
Hi Ciara,
yes, ideally we should avoid usage of version-based check everywhere,
but I don't think that it is critical to switch at once. We can use it
for new checks right now and rewrite old/existing checks a bit later in
the next release.
Please, note that my notes are related to review notes from Thomas who
asked by file_library() method is removed. Yes, it is confusing and it
is better to avoid it. Usage of feature-based checks would allow to
preserve find_library() as well.
Thank you for the explanation.
In this case we want to check that the libbpf library is <=v0.8.0. At this moment
in time v0.8.0 is the latest version of libbpf so we cannot check for a symbol that
tells us the library is > v0.8.0. Can you think of a way to approach this without
using the pkg-config version check method?
I've introduced this check to future-proof the PMD and ensure we only ever link
with versions of libbpf that we've validated to be compatible with the PMD. When
say v0.9.0 is released we can patch the PMD allowing for libbpf <= v0.9.0 and
make any necessary API changes as part of that patch. This should hopefully help
avoid the scenario Thomas encountered.
Personally I'd consider such checks which limit version as a drawback.
I think checks on build should not be used to reject future versions.
Otherwise, introduction of any further even minor version would require
a patch to allow it. Documentation is the place for information about
validated versions. Build should not enforce it.
