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Add zfs_refcount_remove_not_last 

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
This commit is contained in:
Mateusz Guzik 2023-10-28 05:36:57 +00:00
parent 84d0c4d7ec
commit eee1810861
2 changed files with 45 additions and 0 deletions
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4
include/sys/zfs_refcount.h
View File

@ -76,6 +76,8 @@ int zfs_refcount_is_zero(zfs_refcount_t *);
int64_t zfs_refcount_count(zfs_refcount_t *);
int64_t zfs_refcount_add(zfs_refcount_t *, const void *);
int64_t zfs_refcount_remove(zfs_refcount_t *, const void *);
int zfs_refcount_remove_not_last(zfs_refcount_t *, const void *);
/*
* Note that (add|remove)_many adds/removes one reference with "number" N,
* _not_ N references with "number" 1, which is what (add|remove)_few does,
@ -114,6 +116,8 @@ typedef struct refcount {
#define zfs_refcount_count(rc) atomic_load_64(&(rc)->rc_count)
#define zfs_refcount_add(rc, holder) atomic_inc_64_nv(&(rc)->rc_count)
#define zfs_refcount_remove(rc, holder) atomic_dec_64_nv(&(rc)->rc_count)
#define zfs_refcount_remove_not_last(rc, holder) \
atomic_dec_not_last_64(&(rc)->rc_count)
#define zfs_refcount_add_few(rc, number, holder) \
atomic_add_64(&(rc)->rc_count, number)
#define zfs_refcount_remove_few(rc, number, holder) \

41
module/zfs/refcount.c
View File

@ -221,6 +221,47 @@ zfs_refcount_remove_few(zfs_refcount_t *rc, uint64_t number, const void *holder)
(void) zfs_refcount_remove(rc, holder);
}
int
zfs_refcount_remove_not_last(zfs_refcount_t *rc, const void *holder)
{
reference_t *ref, s;
if (likely(!rc->rc_tracked)) {
return (atomic_dec_not_last_64(&(rc)->rc_count));
}
s.ref_holder = holder;
s.ref_number = 1;
s.ref_search = B_TRUE;
mutex_enter(&rc->rc_mtx);
ASSERT3U(rc->rc_count, >=, 1);
ref = avl_find(&rc->rc_tree, &s, NULL);
if (unlikely(ref == NULL)) {
panic("No such hold %p on refcount %llx", holder,
(u_longlong_t)(uintptr_t)rc);
return (0);
}
if (rc->rc_count == 1) {
mutex_exit(&rc->rc_mtx);
return (0);
}
avl_remove(&rc->rc_tree, ref);
if (reference_history > 0) {
list_insert_head(&rc->rc_removed, ref);
if (rc->rc_removed_count >= reference_history) {
ref = list_remove_tail(&rc->rc_removed);
kmem_cache_free(reference_cache, ref);
} else {
rc->rc_removed_count++;
}
} else {
kmem_cache_free(reference_cache, ref);
}
rc->rc_count -= 1;
mutex_exit(&rc->rc_mtx);
return (1);
}
void
zfs_refcount_transfer(zfs_refcount_t *dst, zfs_refcount_t *src)
{