[PATCH] net/af_xdp: make compatible with libbpf v0.8.0

[Ciara Loftus]

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.loftus at 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(-)

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
 static int load_program(const char *prog_path, struct bpf_object **obj)
 {
 	struct bpf_program *prog;
@@ -85,6 +85,23 @@ static int load_program(const char *prog_path, struct bpf_object **obj)
 	bpf_object__close(*obj);
 	return -1;
 }
+
+static int
+remove_xdp_program(int ifindex)
+{
+	uint32_t curr_prog_id = 0;
+
+	if (bpf_xdp_query_id(ifindex, XDP_FLAGS_UPDATE_IF_NOEXIST,
+				&curr_prog_id))
+		return -1;
+
+	return bpf_xdp_detach(ifindex, XDP_FLAGS_UPDATE_IF_NOEXIST, NULL);
+}
+
+static int link_xdp_prog_with_dev(int ifindex, int fd, __u32 flags)
+{
+	return bpf_xdp_attach(ifindex, fd, flags, NULL);
+}
 #else
 static int load_program(const char *prog_path, struct bpf_object **obj)
 {
@@ -96,4 +113,21 @@ static int load_program(const char *prog_path, struct bpf_object **obj)
 
 	return prog_fd;
 }
+
+static int
+remove_xdp_program(int ifindex)
+{
+	uint32_t curr_prog_id = 0;
+
+	if (bpf_get_link_xdp_id(ifindex, &curr_prog_id,
+				XDP_FLAGS_UPDATE_IF_NOEXIST))
+		return -1;
+
+	return bpf_set_link_xdp_fd(ifindex, -1, XDP_FLAGS_UPDATE_IF_NOEXIST);
+}
+
+static int link_xdp_prog_with_dev(int ifindex, int fd, __u32 flags)
+{
+	return bpf_set_link_xdp_fd(ifindex, fd, flags);
+}
 #endif
diff --git a/drivers/net/af_xdp/meson.build b/drivers/net/af_xdp/meson.build
index 1e0de23705..349f8e7c12 100644
--- a/drivers/net/af_xdp/meson.build
+++ b/drivers/net/af_xdp/meson.build
@@ -10,10 +10,7 @@ endif
 sources = files('rte_eth_af_xdp.c')
 
 xdp_dep = dependency('libxdp', version : '>=1.2.2', required: false, method: 'pkg-config')
-bpf_dep = dependency('libbpf', required: false, method: 'pkg-config')
-if not bpf_dep.found()
-    bpf_dep = cc.find_library('bpf', required: false)
-endif
+bpf_dep = dependency('libbpf', version : '<=0.8.0', required: false, method: 'pkg-config')
 
 if cc.has_header('linux/if_xdp.h')
     if xdp_dep.found() and cc.has_header('xdp/xsk.h')
@@ -25,7 +22,7 @@ if cc.has_header('linux/if_xdp.h')
             bpf_ver_dep = dependency('libbpf', version : '>=0.7.0',
                                  required: false, method: 'pkg-config')
             if bpf_ver_dep.found()
-                cflags += ['-DRTE_NET_AF_XDP_LIBBPF_OBJ_OPEN']
+                cflags += ['-DRTE_NET_AF_XDP_LIBBPF_V070']
             endif
         else
             build = false
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 1e37da6e84..943d5c9838 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -863,20 +863,6 @@ eth_stats_reset(struct rte_eth_dev *dev)
 	return 0;
 }
 
-static void
-remove_xdp_program(struct pmd_internals *internals)
-{
-	uint32_t curr_prog_id = 0;
-
-	if (bpf_get_link_xdp_id(internals->if_index, &curr_prog_id,
-				XDP_FLAGS_UPDATE_IF_NOEXIST)) {
-		AF_XDP_LOG(ERR, "bpf_get_link_xdp_id failed\n");
-		return;
-	}
-	bpf_set_link_xdp_fd(internals->if_index, -1,
-			XDP_FLAGS_UPDATE_IF_NOEXIST);
-}
-
 static void
 xdp_umem_destroy(struct xsk_umem_info *umem)
 {
@@ -929,7 +915,8 @@ eth_dev_close(struct rte_eth_dev *dev)
 	 */
 	dev->data->mac_addrs = NULL;
 
-	remove_xdp_program(internals);
+	if (remove_xdp_program(internals->if_index))
+		AF_XDP_LOG(ERR, "Error while removing XDP program.\n");
 
 	if (internals->shared_umem) {
 		struct internal_list *list;
@@ -1195,7 +1182,7 @@ load_custom_xdp_prog(const char *prog_path, int if_index, struct bpf_map **map)
 	}
 
 	/* Link the program with the given network device */
-	ret = bpf_set_link_xdp_fd(if_index, prog_fd,
+	ret = link_xdp_prog_with_dev(if_index, prog_fd,
 					XDP_FLAGS_UPDATE_IF_NOEXIST);
 	if (ret) {
 		AF_XDP_LOG(ERR, "Failed to set prog fd %d on interface\n",
-- 
2.25.1