| Message ID | 20200520084140.18624-1-a@unstable.cc |
|---|---|
| State | Accepted, archived |
| Delegated to: | Simon Wunderlich |
| Headers | show |
| Series | batman-adv: use rcu_replace_pointer() where appropriate | expand |
On Wednesday, 20 May 2020 10:41:40 CEST Antonio Quartulli wrote: > In a63fc6b7 ("rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()") > a new helper macro named rcu_replace_pointer() was introduced to > simplify code requiring to switch an rcu pointer to a new value while > extracting the old one. Please use the reference style 'commit a63fc6b75cca ("rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()")' in the future [1]. checkpatch will also report something like this when it detects a short commit id: ERROR: Please use git commit description style 'commit <12+ chars of sha1> ("<title line>")' - ie: 'commit a63fc6b75cca ("rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()")' I will change this for you. [...] > +#if LINUX_VERSION_IS_LESS(5, 5, 0) > + > +#define rcu_replace_pointer(rcu_ptr, ptr, c) \ > +({ \ > + typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \ > + rcu_assign_pointer((rcu_ptr), (ptr)); \ > + __tmp; \ > +}) > + > +#endif /* LINUX_VERSION_IS_LESS(5, 5, 0) */ To avoid problems with a (potentially) backported patch in the stable kernels - please #undef rcu_replace_pointer first. I will do this for you. Applied. Thanks, Sven [1] https://www.kernel.org/doc/html/v4.17/process/submitting-patches.html#describe-your-changes
diff --git a/compat-include/linux/rcupdate.h b/compat-include/linux/rcupdate.h new file mode 100644 index 00000000..731aa951 --- /dev/null +++ b/compat-include/linux/rcupdate.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (C) 2020 B.A.T.M.A.N. contributors: + * + * Antonio Quartulli + * + * This file contains macros for maintaining compatibility with older versions + * of the Linux kernel. + */ + +#ifndef _NET_BATMAN_ADV_COMPAT_LINUX_RCUPDATE_H_ +#define _NET_BATMAN_ADV_COMPAT_LINUX_RCUPDATE_H_ + +#include <linux/version.h> +#include_next <linux/rcupdate.h> + +#if LINUX_VERSION_IS_LESS(5, 5, 0) + +#define rcu_replace_pointer(rcu_ptr, ptr, c) \ +({ \ + typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \ + rcu_assign_pointer((rcu_ptr), (ptr)); \ + __tmp; \ +}) + +#endif /* LINUX_VERSION_IS_LESS(5, 5, 0) */ + +#endif /* _NET_BATMAN_ADV_COMPAT_LINUX_RCUPDATE_H_ */ diff --git a/net/batman-adv/gateway_client.c b/net/batman-adv/gateway_client.c index e22e4928..a18dcc68 100644 --- a/net/batman-adv/gateway_client.c +++ b/net/batman-adv/gateway_client.c @@ -146,8 +146,8 @@ static void batadv_gw_select(struct batadv_priv *bat_priv, if (new_gw_node) kref_get(&new_gw_node->refcount); - curr_gw_node = rcu_dereference_protected(bat_priv->gw.curr_gw, 1); - rcu_assign_pointer(bat_priv->gw.curr_gw, new_gw_node); + curr_gw_node = rcu_replace_pointer(bat_priv->gw.curr_gw, new_gw_node, + true); if (curr_gw_node) batadv_gw_node_put(curr_gw_node); diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c index c7e98a40..3a256af9 100644 --- a/net/batman-adv/hard-interface.c +++ b/net/batman-adv/hard-interface.c @@ -473,8 +473,8 @@ static void batadv_primary_if_select(struct batadv_priv *bat_priv, if (new_hard_iface) kref_get(&new_hard_iface->refcount); - curr_hard_iface = rcu_dereference_protected(bat_priv->primary_if, 1); - rcu_assign_pointer(bat_priv->primary_if, new_hard_iface); + curr_hard_iface = rcu_replace_pointer(bat_priv->primary_if, + new_hard_iface, 1); if (!new_hard_iface) goto out; diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 3632bd97..d343382e 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -71,13 +71,13 @@ static void _batadv_update_route(struct batadv_priv *bat_priv, * the code needs to ensure the curr_router variable contains a pointer * to the replaced best neighbor. */ - curr_router = rcu_dereference_protected(orig_ifinfo->router, true); /* increase refcount of new best neighbor */ if (neigh_node) kref_get(&neigh_node->refcount); - rcu_assign_pointer(orig_ifinfo->router, neigh_node); + curr_router = rcu_replace_pointer(orig_ifinfo->router, neigh_node, + true); spin_unlock_bh(&orig_node->neigh_list_lock); batadv_orig_ifinfo_put(orig_ifinfo);
In a63fc6b7 ("rcu: Upgrade rcu_swap_protected() to rcu_replace_pointer()") a new helper macro named rcu_replace_pointer() was introduced to simplify code requiring to switch an rcu pointer to a new value while extracting the old one. Use rcu_replace_pointer() where appropriate to make code slimer. Signed-off-by: Antonio Quartulli <a@unstable.cc> --- compat-include/linux/rcupdate.h | 27 +++++++++++++++++++++++++++ net/batman-adv/gateway_client.c | 4 ++-- net/batman-adv/hard-interface.c | 4 ++-- net/batman-adv/routing.c | 4 ++-- 4 files changed, 33 insertions(+), 6 deletions(-) create mode 100644 compat-include/linux/rcupdate.h