a7462d7032
In commit 92f1655aa2b2 ("net: fix __dst_negative_advice() race") the
struct dst_ops callback negative_advice is callback changes function
parameters. But as this pointer is part of a structure that is tracked
in the ABI checker, the tool triggers when this is changed.
However, the callback pointer is internal to the networking stack, so
changing the function type is safe, so needing to preserve this is not
required. To do so, switch the function pointer type back to the old
one so that the checking tools pass, AND then do a hard cast of the
function pointer to the new type when assigning and calling the
function.
[6.1.y backport note, work around --Werror=cast-function-type issue by
abusing void * for function pointer types, despite its best effort, C
still let's us shoot our foot off if we really want to!]
Bug: 343727534
Fixes: 92f1655aa2b2 ("net: fix __dst_negative_advice() race")
Change-Id: I48d4ab4bbd29f8edc8fbd7923828b7f78a23e12e
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
84 lines
2.5 KiB
C
84 lines
2.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _NET_DST_OPS_H
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#define _NET_DST_OPS_H
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#include <linux/types.h>
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#include <linux/percpu_counter.h>
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#include <linux/cache.h>
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struct dst_entry;
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struct kmem_cachep;
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struct net_device;
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struct sk_buff;
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struct sock;
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struct net;
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/* *** ANDROID FIXUP ***
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* These typedefs are used to help fixup the ABI break caused by commit
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* 92f1655aa2b2 ("net: fix __dst_negative_advice() race") where the
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* negative_advice callback changed function signatures.
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* See b/343727534 for more details.
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* *** ANDROID FIXUP ***
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*/
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typedef void (*android_dst_ops_negative_advice_new_t)(struct sock *sk, struct dst_entry *);
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typedef struct dst_entry * (*android_dst_ops_negative_advice_old_t)(struct dst_entry *);
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struct dst_ops {
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unsigned short family;
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unsigned int gc_thresh;
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int (*gc)(struct dst_ops *ops);
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struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
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unsigned int (*default_advmss)(const struct dst_entry *);
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unsigned int (*mtu)(const struct dst_entry *);
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u32 * (*cow_metrics)(struct dst_entry *, unsigned long);
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void (*destroy)(struct dst_entry *);
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void (*ifdown)(struct dst_entry *,
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struct net_device *dev, int how);
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struct dst_entry * (*negative_advice)(struct dst_entry *);
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void (*link_failure)(struct sk_buff *);
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void (*update_pmtu)(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb, u32 mtu,
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bool confirm_neigh);
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void (*redirect)(struct dst_entry *dst, struct sock *sk,
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struct sk_buff *skb);
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int (*local_out)(struct net *net, struct sock *sk, struct sk_buff *skb);
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struct neighbour * (*neigh_lookup)(const struct dst_entry *dst,
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struct sk_buff *skb,
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const void *daddr);
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void (*confirm_neigh)(const struct dst_entry *dst,
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const void *daddr);
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struct kmem_cache *kmem_cachep;
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struct percpu_counter pcpuc_entries ____cacheline_aligned_in_smp;
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};
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static inline int dst_entries_get_fast(struct dst_ops *dst)
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{
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return percpu_counter_read_positive(&dst->pcpuc_entries);
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}
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static inline int dst_entries_get_slow(struct dst_ops *dst)
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{
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return percpu_counter_sum_positive(&dst->pcpuc_entries);
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}
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#define DST_PERCPU_COUNTER_BATCH 32
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static inline void dst_entries_add(struct dst_ops *dst, int val)
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{
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percpu_counter_add_batch(&dst->pcpuc_entries, val,
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DST_PERCPU_COUNTER_BATCH);
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}
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static inline int dst_entries_init(struct dst_ops *dst)
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{
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return percpu_counter_init(&dst->pcpuc_entries, 0, GFP_KERNEL);
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}
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static inline void dst_entries_destroy(struct dst_ops *dst)
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{
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percpu_counter_destroy(&dst->pcpuc_entries);
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}
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#endif
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