Evolution-X-Devices/kernel_xiaomi_garnet
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Revert "bpf: Defer the free of inner map when necessary"

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This reverts commit 90c445799f which is
commit 876673364161da50eed6b472d746ef88242b2368 upstream.

It breaks the Android kernel build AND the kernel abi and can be brought
back in the future in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I8c7820bcca06e847cdc7c894005d383a2ac828a0
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
This commit is contained in:
Greg Kroah-Hartman
2024-05-16 13:13:44 +00:00
parent 38a24db1c2
commit e2ddf25269
3 changed files with 6 additions and 38 deletions
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7
include/linux/bpf.h
View File

@@ -175,11 +175,7 @@ struct bpf_map {
*/
atomic64_t refcnt ____cacheline_aligned;
atomic64_t usercnt;
/* rcu is used before freeing and work is only used during freeing */
union {
struct work_struct work;
struct rcu_head rcu;
};
struct work_struct work;
struct mutex freeze_mutex;
#ifdef __GENKSYMS__
/* Preserve the CRC change that commit 33fe044f6a9e ("bpf: Fix toctou on
@@ -189,7 +185,6 @@ struct bpf_map {
#else
atomic64_t writecnt;
#endif
bool free_after_mult_rcu_gp;
};
static inline bool map_value_has_spin_lock(const struct bpf_map *map)

11
kernel/bpf/map_in_map.c
View File

@@ -102,15 +102,10 @@ void *bpf_map_fd_get_ptr(struct bpf_map *map,
void bpf_map_fd_put_ptr(void *ptr)
{
struct bpf_map *inner_map = ptr;
/* The inner map may still be used by both non-sleepable and sleepable
* bpf program, so free it after one RCU grace period and one tasks
* trace RCU grace period.
/* ptr->ops->map_free() has to go through one
* rcu grace period by itself.
*/
if (need_defer)
WRITE_ONCE(inner_map->free_after_mult_rcu_gp, true);
bpf_map_put(inner_map);
bpf_map_put(ptr);
}
u32 bpf_map_fd_sys_lookup_elem(void *ptr)

26
kernel/bpf/syscall.c
View File

@@ -495,25 +495,6 @@ static void bpf_map_put_uref(struct bpf_map *map)
}
}
static void bpf_map_free_in_work(struct bpf_map *map)
{
INIT_WORK(&map->work, bpf_map_free_deferred);
schedule_work(&map->work);
}
static void bpf_map_free_rcu_gp(struct rcu_head *rcu)
{
bpf_map_free_in_work(container_of(rcu, struct bpf_map, rcu));
}
static void bpf_map_free_mult_rcu_gp(struct rcu_head *rcu)
{
if (rcu_trace_implies_rcu_gp())
bpf_map_free_rcu_gp(rcu);
else
call_rcu(rcu, bpf_map_free_rcu_gp);
}
/* decrement map refcnt and schedule it for freeing via workqueue
* (unrelying map implementation ops->map_free() might sleep)
*/
@@ -523,11 +504,8 @@ static void __bpf_map_put(struct bpf_map *map, bool do_idr_lock)
/* bpf_map_free_id() must be called first */
bpf_map_free_id(map, do_idr_lock);
btf_put(map->btf);
if (READ_ONCE(map->free_after_mult_rcu_gp))
call_rcu_tasks_trace(&map->rcu, bpf_map_free_mult_rcu_gp);
else
bpf_map_free_in_work(map);
INIT_WORK(&map->work, bpf_map_free_deferred);
schedule_work(&map->work);
}
}