Re: [tip: locking/core] bcache: Convert to lock_cmp_fn

Coly Li
2023-05-21T13:36:55Z

> 2023年5月20日 18:49，tip-bot2 for Kent Overstreet <tip-bot2@linutronix.de> 写道：
>
> The following commit has been merged into the locking/core branch of tip:
>
> Commit-ID: 0ad397b556936a14052aa65d8fa958a9f3175add
> Gitweb: https://git.kernel.org/tip/0ad397b556936a14052aa65d8fa958a9f3175add
> Author: Kent Overstreet <kent.overstreet@linux.dev>
> AuthorDate: Tue, 09 May 2023 15:58:47 -04:00
> Committer: Peter Zijlstra <peterz@infradead.org>
> CommitterDate: Fri, 19 May 2023 12:35:10 +02:00
>
> bcache: Convert to lock_cmp_fn
>
> Replace one of bcache's lockdep_set_novalidate_class() usage with the
> newly introduced custom lock nesting annotation.
>
> [peterz: changelog]
> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Acked-by: Coly Li <colyli@suse.de <mailto:colyli@suse.de>>

Can the above “<mailto:colyli@suse.de>” be removed from my acked-by. This was automatically and invisibly added by MacOS email client, which just introduced chaos in such use case.

Thanks.

Coly Li

> Link: https://lkml.kernel.org/r/20230509195847.1745548-2-kent.overstreet@linux.dev
> ---
> drivers/md/bcache/btree.c | 23 ++++++++++++++++++++++-
> drivers/md/bcache/btree.h | 4 ++--
> 2 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
> index 147c493..569f489 100644
> --- a/drivers/md/bcache/btree.c
> +++ b/drivers/md/bcache/btree.c
> @@ -559,6 +559,27 @@ static void mca_data_alloc(struct btree *b, struct bkey *k, gfp_t gfp)
> }
> }
>
> +#define cmp_int(l, r) ((l > r) - (l < r))
> +
> +#ifdef CONFIG_PROVE_LOCKING
> +static int btree_lock_cmp_fn(const struct lockdep_map *_a,
> + const struct lockdep_map *_b)
> +{
> + const struct btree *a = container_of(_a, struct btree, lock.dep_map);
> + const struct btree *b = container_of(_b, struct btree, lock.dep_map);
> +
> + return -cmp_int(a->level, b->level) ?: bkey_cmp(&a->key, &b->key);
> +}
> +
> +static void btree_lock_print_fn(const struct lockdep_map *map)
> +{
> + const struct btree *b = container_of(map, struct btree, lock.dep_map);
> +
> + printk(KERN_CONT " l=%u %llu:%llu", b->level,
> + KEY_INODE(&b->key), KEY_OFFSET(&b->key));
> +}
> +#endif
> +
> static struct btree *mca_bucket_alloc(struct cache_set *c,
> struct bkey *k, gfp_t gfp)
> {
> @@ -572,7 +593,7 @@ static struct btree *mca_bucket_alloc(struct cache_set *c,
> return NULL;
>
> init_rwsem(&b->lock);
> - lockdep_set_novalidate_class(&b->lock);
> + lock_set_cmp_fn(&b->lock, btree_lock_cmp_fn, btree_lock_print_fn);
> mutex_init(&b->write_lock);
> lockdep_set_novalidate_class(&b->write_lock);
> INIT_LIST_HEAD(&b->list);
> diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
> index 1b5fdbc..17b1d20 100644
> --- a/drivers/md/bcache/btree.h
> +++ b/drivers/md/bcache/btree.h
> @@ -247,8 +247,8 @@ static inline void bch_btree_op_init(struct btree_op *op, int write_lock_level)
>
> static inline void rw_lock(bool w, struct btree *b, int level)
> {
> - w ? down_write_nested(&b->lock, level + 1)
> - : down_read_nested(&b->lock, level + 1);
> + w ? down_write(&b->lock)
> + : down_read(&b->lock);
> if (w)
> b->seq++;
> }