Merge branch 'selftests-net-exercise-page-pool-reporting-via-netlink'

Jakub Kicinski says:

====================
selftests: net: exercise page pool reporting via netlink

Add a basic test for page pool netlink reporting.

v1: https://lore.kernel.org/all/20240411012815.174400-1-kuba@kernel.org/
====================

Link: https://lore.kernel.org/r/20240412141436.828666-1-kuba@kernel.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/netdevsim/netdev.c

@@ -20,6 +20,7 @@
 #include <linux/netdevice.h>
 #include <linux/slab.h>
 #include <net/netdev_queues.h>
+#include <net/page_pool/helpers.h>
 #include <net/netlink.h>
 #include <net/pkt_cls.h>
 #include <net/rtnetlink.h>
@@ -299,6 +300,29 @@ static int nsim_get_iflink(const struct net_device *dev)
 	return iflink;
 }
 
+static int nsim_open(struct net_device *dev)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+	struct page_pool_params pp = { 0 };
+
+	pp.pool_size = 128;
+	pp.dev = &dev->dev;
+	pp.dma_dir = DMA_BIDIRECTIONAL;
+	pp.netdev = dev;
+
+	ns->pp = page_pool_create(&pp);
+	return PTR_ERR_OR_ZERO(ns->pp);
+}
+
+static int nsim_stop(struct net_device *dev)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	page_pool_destroy(ns->pp);
+
+	return 0;
+}
+
 static const struct net_device_ops nsim_netdev_ops = {
 	.ndo_start_xmit		= nsim_start_xmit,
 	.ndo_set_rx_mode	= nsim_set_rx_mode,
@@ -318,6 +342,8 @@ static const struct net_device_ops nsim_netdev_ops = {
 	.ndo_set_features	= nsim_set_features,
 	.ndo_get_iflink		= nsim_get_iflink,
 	.ndo_bpf		= nsim_bpf,
+	.ndo_open		= nsim_open,
+	.ndo_stop		= nsim_stop,
 };
 
 static const struct net_device_ops nsim_vf_netdev_ops = {
@@ -378,6 +404,60 @@ static const struct netdev_stat_ops nsim_stat_ops = {
 	.get_base_stats		= nsim_get_base_stats,
 };
 
+static ssize_t
+nsim_pp_hold_read(struct file *file, char __user *data,
+		  size_t count, loff_t *ppos)
+{
+	struct netdevsim *ns = file->private_data;
+	char buf[3] = "n\n";
+
+	if (ns->page)
+		buf[0] = 'y';
+
+	return simple_read_from_buffer(data, count, ppos, buf, 2);
+}
+
+static ssize_t
+nsim_pp_hold_write(struct file *file, const char __user *data,
+		   size_t count, loff_t *ppos)
+{
+	struct netdevsim *ns = file->private_data;
+	ssize_t ret;
+	bool val;
+
+	ret = kstrtobool_from_user(data, count, &val);
+	if (ret)
+		return ret;
+
+	rtnl_lock();
+	ret = count;
+	if (val == !!ns->page)
+		goto exit;
+
+	if (!netif_running(ns->netdev) && val) {
+		ret = -ENETDOWN;
+	} else if (val) {
+		ns->page = page_pool_dev_alloc_pages(ns->pp);
+		if (!ns->page)
+			ret = -ENOMEM;
+	} else {
+		page_pool_put_full_page(ns->page->pp, ns->page, false);
+		ns->page = NULL;
+	}
+	rtnl_unlock();
+
+exit:
+	return count;
+}
+
+static const struct file_operations nsim_pp_hold_fops = {
+	.open = simple_open,
+	.read = nsim_pp_hold_read,
+	.write = nsim_pp_hold_write,
+	.llseek = generic_file_llseek,
+	.owner = THIS_MODULE,
+};
+
 static void nsim_setup(struct net_device *dev)
 {
 	ether_setup(dev);
@@ -485,6 +565,10 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
 		err = nsim_init_netdevsim_vf(ns);
 	if (err)
 		goto err_free_netdev;
+
+	ns->pp_dfs = debugfs_create_file("pp_hold", 0600, nsim_dev_port->ddir,
+					 ns, &nsim_pp_hold_fops);
+
 	return ns;
 
 err_free_netdev:
@@ -497,6 +581,8 @@ void nsim_destroy(struct netdevsim *ns)
 	struct net_device *dev = ns->netdev;
 	struct netdevsim *peer;
 
+	debugfs_remove(ns->pp_dfs);
+
 	rtnl_lock();
 	peer = rtnl_dereference(ns->peer);
 	if (peer)
@@ -511,6 +597,13 @@ void nsim_destroy(struct netdevsim *ns)
 	rtnl_unlock();
 	if (nsim_dev_port_is_pf(ns->nsim_dev_port))
 		nsim_exit_netdevsim(ns);
+
+	/* Put this intentionally late to exercise the orphaning path */
+	if (ns->page) {
+		page_pool_put_full_page(ns->page->pp, ns->page, false);
+		ns->page = NULL;
+	}
+
 	free_netdev(dev);
 }
 

drivers/net/netdevsim/netdevsim.h

@@ -125,6 +125,10 @@ struct netdevsim {
 		struct debugfs_u32_array dfs_ports[2];
 	} udp_ports;
 
+	struct page_pool *pp;
+	struct page *page;
+	struct dentry *pp_dfs;
+
 	struct nsim_ethtool ethtool;
 	struct netdevsim __rcu *peer;
 };

tools/net/ynl/lib/ynl.py

@@ -995,9 +995,11 @@ class YnlFamily(SpecFamily):
                     rsp_msg.update(self._decode_struct(decoded.raw, op.fixed_header))
                 rsp.append(rsp_msg)
 
+        if dump:
+            return rsp
         if not rsp:
             return None
-        if not dump and len(rsp) == 1:
+        if len(rsp) == 1:
             return rsp[0]
         return rsp
 

tools/testing/selftests/net/lib/py/ksft.py

 # SPDX-License-Identifier: GPL-2.0
 
 import builtins
+import inspect
+import time
+import traceback
 from .consts import KSFT_MAIN_NAME
 
 KSFT_RESULT = None
@@ -18,32 +21,45 @@ def ksft_pr(*objs, **kwargs):
     print("#", *objs, **kwargs)
 
 
+def _fail(*args):
+    global KSFT_RESULT
+    KSFT_RESULT = False
+
+    frame = inspect.stack()[2]
+    ksft_pr("At " + frame.filename + " line " + str(frame.lineno) + ":")
+    ksft_pr(*args)
+
+
 def ksft_eq(a, b, comment=""):
     global KSFT_RESULT
     if a != b:
-        KSFT_RESULT = False
-        ksft_pr("Check failed", a, "!=", b, comment)
+        _fail("Check failed", a, "!=", b, comment)
 
 
 def ksft_true(a, comment=""):
-    global KSFT_RESULT
     if not a:
-        KSFT_RESULT = False
-        ksft_pr("Check failed", a, "does not eval to True", comment)
+        _fail("Check failed", a, "does not eval to True", comment)
 
 
 def ksft_in(a, b, comment=""):
-    global KSFT_RESULT
     if a not in b:
-        KSFT_RESULT = False
-        ksft_pr("Check failed", a, "not in", b, comment)
+        _fail("Check failed", a, "not in", b, comment)
 
 
 def ksft_ge(a, b, comment=""):
-    global KSFT_RESULT
     if a < b:
-        KSFT_RESULT = False
-        ksft_pr("Check failed", a, "<", b, comment)
+        _fail("Check failed", a, "<", b, comment)
+
+
+def ksft_busy_wait(cond, sleep=0.005, deadline=1, comment=""):
+    end = time.monotonic() + deadline
+    while True:
+        if cond():
+            return
+        if time.monotonic() > end:
+            _fail("Waiting for condition timed out", comment)
+            return
+        time.sleep(sleep)
 
 
 def ktap_result(ok, cnt=1, case="", comment=""):
@@ -82,7 +98,8 @@ def ksft_run(cases, args=()):
             totals['xfail'] += 1
             continue
         except Exception as e:
-            for line in str(e).split('\n'):
+            tb = traceback.format_exc()
+            for line in tb.strip().split('\n'):
                 ksft_pr("Exception|", line)
             ktap_result(False, cnt, case)
             totals['fail'] += 1

tools/testing/selftests/net/lib/py/nsim.py

@@ -28,6 +28,7 @@ class NetdevSim:
         self.dfs_dir = "%s/ports/%u/" % (nsimdev.dfs_dir, port_index)
         ret = ip("-j link show dev %s" % ifname, ns=ns)
         self.dev = json.loads(ret.stdout)[0]
+        self.ifindex = self.dev["ifindex"]
 
     def dfs_write(self, path, val):
         self.nsimdev.dfs_write(f'ports/{self.port_index}/' + path, val)
@@ -84,6 +85,17 @@ class NetdevSimDev:
         for port_index in range(port_count):
             self.nsims.append(self._make_port(port_index, ifnames[port_index]))
 
+        self.removed = False
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, ex_type, ex_value, ex_tb):
+        """
+        __exit__ gets called at the end of a "with" block.
+        """
+        self.remove()
+
     def _make_port(self, port_index, ifname):
         return NetdevSim(self, port_index, ifname, self.ns)
 
@@ -112,7 +124,9 @@ class NetdevSimDev:
             raise Exception("netdevices did not appear within timeout")
 
     def remove(self):
-        self.ctrl_write("del_device", "%u" % (self.addr, ))
+        if not self.removed:
+            self.ctrl_write("del_device", "%u" % (self.addr, ))
+            self.removed = True
 
     def remove_nsim(self, nsim):
         self.nsims.remove(nsim)

tools/testing/selftests/net/nl_netdev.py

 #!/usr/bin/env python3
 # SPDX-License-Identifier: GPL-2.0
 
-from lib.py import ksft_run, ksft_pr, ksft_eq, ksft_ge, NetdevFamily
+import time
+from lib.py import ksft_run, ksft_pr, ksft_eq, ksft_ge, ksft_busy_wait
+from lib.py import NetdevFamily, NetdevSimDev, ip
 
 
 def empty_check(nf) -> None:
@@ -15,9 +17,79 @@ def lo_check(nf) -> None:
     ksft_eq(len(lo_info['xdp-rx-metadata-features']), 0)
 
 
+def page_pool_check(nf) -> None:
+    with NetdevSimDev() as nsimdev:
+        nsim = nsimdev.nsims[0]
+
+        def up():
+            ip(f"link set dev {nsim.ifname} up")
+
+        def down():
+            ip(f"link set dev {nsim.ifname} down")
+
+        def get_pp():
+            pp_list = nf.page_pool_get({}, dump=True)
+            return [pp for pp in pp_list if pp.get("ifindex") == nsim.ifindex]
+
+        # No page pools when down
+        down()
+        ksft_eq(len(get_pp()), 0)
+
+        # Up, empty page pool appears
+        up()
+        pp_list = get_pp()
+        ksft_ge(len(pp_list), 0)
+        refs = sum([pp["inflight"] for pp in pp_list])
+        ksft_eq(refs, 0)
+
+        # Down, it disappears, again
+        down()
+        pp_list = get_pp()
+        ksft_eq(len(pp_list), 0)
+
+        # Up, allocate a page
+        up()
+        nsim.dfs_write("pp_hold", "y")
+        pp_list = nf.page_pool_get({}, dump=True)
+        refs = sum([pp["inflight"] for pp in pp_list if pp.get("ifindex") == nsim.ifindex])
+        ksft_ge(refs, 1)
+
+        # Now let's leak a page
+        down()
+        pp_list = get_pp()
+        ksft_eq(len(pp_list), 1)
+        refs = sum([pp["inflight"] for pp in pp_list])
+        ksft_eq(refs, 1)
+        attached = [pp for pp in pp_list if "detach-time" not in pp]
+        ksft_eq(len(attached), 0)
+
+        # New pp can get created, and we'll have two
+        up()
+        pp_list = get_pp()
+        attached = [pp for pp in pp_list if "detach-time" not in pp]
+        detached = [pp for pp in pp_list if "detach-time" in pp]
+        ksft_eq(len(attached), 1)
+        ksft_eq(len(detached), 1)
+
+        # Free the old page and the old pp is gone
+        nsim.dfs_write("pp_hold", "n")
+        # Freeing check is once a second so we may need to retry
+        ksft_busy_wait(lambda: len(get_pp()) == 1, deadline=2)
+
+        # And down...
+        down()
+        ksft_eq(len(get_pp()), 0)
+
+        # Last, leave the page hanging for destroy, nothing to check
+        # we're trying to exercise the orphaning path in the kernel
+        up()
+        nsim.dfs_write("pp_hold", "y")
+
+
 def main() -> None:
     nf = NetdevFamily()
-    ksft_run([empty_check, lo_check], args=(nf, ))
+    ksft_run([empty_check, lo_check, page_pool_check],
+             args=(nf, ))
 
 
 if __name__ == "__main__":