Re: [PATCH v2 04/20] dissolve external_name.u into separate members

Jan Kara
2025-01-16T10:06:22Z

On Thu 16-01-25 05:23:01, Al Viro wrote:
> kept separate from the previous commit to keep the noise separate
> from actual changes...
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/dcache.c | 22 ++++++++++------------
> 1 file changed, 10 insertions(+), 12 deletions(-)
>
> diff --git a/fs/dcache.c b/fs/dcache.c
> index f387dc97df86..6f36d3e8c739 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -296,10 +296,8 @@ static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *c
> }
>
> struct external_name {
> - struct {
> - atomic_t count; // ->count and ->head can't be combined
> - struct rcu_head head; // see take_dentry_name_snapshot()
> - } u;
> + struct rcu_head head; // ->head and ->count can't be combined
> + atomic_t count; // see take_dentry_name_snapshot()
> unsigned char name[];
> };
>
> @@ -344,7 +342,7 @@ void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry
> struct external_name *p;
> p = container_of(s, struct external_name, name[0]);
> // get a valid reference
> - if (unlikely(!atomic_inc_not_zero(&p->u.count)))
> + if (unlikely(!atomic_inc_not_zero(&p->count)))
> goto retry;
> name->name.name = s;
> }
> @@ -361,8 +359,8 @@ void release_dentry_name_snapshot(struct name_snapshot *name)
> if (unlikely(name->name.name != name->inline_name.string)) {
> struct external_name *p;
> p = container_of(name->name.name, struct external_name, name[0]);
> - if (unlikely(atomic_dec_and_test(&p->u.count)))
> - kfree_rcu(p, u.head);
> + if (unlikely(atomic_dec_and_test(&p->count)))
> + kfree_rcu(p, head);
> }
> }
> EXPORT_SYMBOL(release_dentry_name_snapshot);
> @@ -400,7 +398,7 @@ static void dentry_free(struct dentry *dentry)
> WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
> if (unlikely(dname_external(dentry))) {
> struct external_name *p = external_name(dentry);
> - if (likely(atomic_dec_and_test(&p->u.count))) {
> + if (likely(atomic_dec_and_test(&p->count))) {
> call_rcu(&dentry->d_u.d_rcu, __d_free_external);
> return;
> }
> @@ -1681,7 +1679,7 @@ static struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name)
> kmem_cache_free(dentry_cache, dentry);
> return NULL;
> }
> - atomic_set(&p->u.count, 1);
> + atomic_set(&p->count, 1);
> dname = p->name;
> } else {
> dname = dentry->d_shortname.string;
> @@ -2774,15 +2772,15 @@ static void copy_name(struct dentry *dentry, struct dentry *target)
> if (unlikely(dname_external(dentry)))
> old_name = external_name(dentry);
> if (unlikely(dname_external(target))) {
> - atomic_inc(&external_name(target)->u.count);
> + atomic_inc(&external_name(target)->count);
> dentry->d_name = target->d_name;
> } else {
> dentry->d_shortname = target->d_shortname;
> dentry->d_name.name = dentry->d_shortname.string;
> dentry->d_name.hash_len = target->d_name.hash_len;
> }
> - if (old_name && likely(atomic_dec_and_test(&old_name->u.count)))
> - kfree_rcu(old_name, u.head);
> + if (old_name && likely(atomic_dec_and_test(&old_name->count)))
> + kfree_rcu(old_name, head);
> }
>
> /*
> --
> 2.39.5
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR