Commit c2368b19 authored by Jiri Pirko's avatar Jiri Pirko Committed by David S. Miller
Browse files

net: devlink: introduce "unregistering" mark and use it during devlinks iteration 



Add new mark called "unregistering" to be set at the beginning of
devlink_unregister() function. Check this mark during devlinks
iteration in order to prevent getting a reference of devlink which is
being currently unregistered.

Signed-off-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 02a7cb28

net/core/devlink.c

+11 −0
Original line number Diff line number Diff line
@@ -207,6 +207,7 @@ static const struct nla_policy devlink_selftest_nl_policy[DEVLINK_ATTR_SELFTEST_ 


static DEFINE_XARRAY_FLAGS(devlinks, XA_FLAGS_ALLOC);

#define DEVLINK_REGISTERED XA_MARK_1

#define DEVLINK_UNREGISTERING XA_MARK_2



/* devlink instances are open to the access from the user space after

 * devlink_register() call. Such logical barrier allows us to have certain
@@ -305,6 +306,14 @@ devlinks_xa_find_get(struct net *net, unsigned long *indexp, xa_mark_t filter, 
	devlink = xa_find_fn(&devlinks, indexp, ULONG_MAX, DEVLINK_REGISTERED);

	if (!devlink)

		goto unlock;



	/* In case devlink_unregister() was already called and "unregistering"

	 * mark was set, do not allow to get a devlink reference here.

	 * This prevents live-lock of devlink_unregister() wait for completion.

	 */

	if (xa_get_mark(&devlinks, *indexp, DEVLINK_UNREGISTERING))

		goto retry;



	/* For a possible retry, the xa_find_after() should be always used */

	xa_find_fn = xa_find_after;

	if (!devlink_try_get(devlink))
@@ -9809,11 +9818,13 @@ void devlink_unregister(struct devlink *devlink) 
	ASSERT_DEVLINK_REGISTERED(devlink);

	/* Make sure that we are in .remove() routine */



	xa_set_mark(&devlinks, devlink->index, DEVLINK_UNREGISTERING);

	devlink_put(devlink);

	wait_for_completion(&devlink->comp);



	devlink_notify_unregister(devlink);

	xa_clear_mark(&devlinks, devlink->index, DEVLINK_REGISTERED);

	xa_clear_mark(&devlinks, devlink->index, DEVLINK_UNREGISTERING);

}

EXPORT_SYMBOL_GPL(devlink_unregister);