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net: netdevsim: add some fake page pool use

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Add very basic page pool use so that we can exercise
the netlink uAPI in a selftest.

Page pool gets created on open, destroyed on close.
But we control allocating of a single page thru debugfs.
This page may survive past the page pool itself so that
we can test orphaned page pools.

Link: https://lore.kernel.org/r/20240412141436.828666-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Jakub Kicinski 2024-04-12 07:14:31 -07:00
parent 77c842caa7
commit 1580cbcbfe
2 changed files with 97 additions and 0 deletions
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93
drivers/net/netdevsim/netdev.c
View File

@ -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);
}

4
drivers/net/netdevsim/netdevsim.h
View File

@ -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;
};