From 246779dd090bd1b74d2652b3a6ca7759f593b27a Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Thu, 18 Aug 2016 16:50:56 +0800 Subject: [PATCH] rhashtable: Remove GFP flag from rhashtable_walk_init The commit 8f6fd83c6c5ec66a4a70c728535ddcdfef4f3697 ("rhashtable: accept GFP flags in rhashtable_walk_init") added a GFP flag argument to rhashtable_walk_init because some users wish to use the walker in an unsleepable context. In fact we don't need to allocate memory in rhashtable_walk_init at all. The walker is always paired with an iterator so we could just stash ourselves there. This patch does that by introducing a new enter function to replace the existing init function. This way we don't have to churn all the existing users again. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/linux/rhashtable.h | 14 +++++++++--- lib/rhashtable.c | 46 +++++++++++++++----------------------- 2 files changed, 29 insertions(+), 31 deletions(-) diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h index 3eef0802a0cd..8b72ee710f95 100644 --- a/include/linux/rhashtable.h +++ b/include/linux/rhashtable.h @@ -173,7 +173,7 @@ struct rhashtable_walker { struct rhashtable_iter { struct rhashtable *ht; struct rhash_head *p; - struct rhashtable_walker *walker; + struct rhashtable_walker walker; unsigned int slot; unsigned int skip; }; @@ -346,8 +346,8 @@ struct bucket_table *rhashtable_insert_slow(struct rhashtable *ht, struct bucket_table *old_tbl); int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl); -int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter, - gfp_t gfp); +void rhashtable_walk_enter(struct rhashtable *ht, + struct rhashtable_iter *iter); void rhashtable_walk_exit(struct rhashtable_iter *iter); int rhashtable_walk_start(struct rhashtable_iter *iter) __acquires(RCU); void *rhashtable_walk_next(struct rhashtable_iter *iter); @@ -906,4 +906,12 @@ static inline int rhashtable_replace_fast( return err; } +/* Obsolete function, do not use in new code. */ +static inline int rhashtable_walk_init(struct rhashtable *ht, + struct rhashtable_iter *iter, gfp_t gfp) +{ + rhashtable_walk_enter(ht, iter); + return 0; +} + #endif /* _LINUX_RHASHTABLE_H */ diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 5ba520b544d7..97e3cf08142c 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -489,10 +489,9 @@ exit: EXPORT_SYMBOL_GPL(rhashtable_insert_slow); /** - * rhashtable_walk_init - Initialise an iterator + * rhashtable_walk_enter - Initialise an iterator * @ht: Table to walk over * @iter: Hash table Iterator - * @gfp: GFP flags for allocations * * This function prepares a hash table walk. * @@ -507,30 +506,22 @@ EXPORT_SYMBOL_GPL(rhashtable_insert_slow); * This function may sleep so you must not call it from interrupt * context or with spin locks held. * - * You must call rhashtable_walk_exit if this function returns - * successfully. + * You must call rhashtable_walk_exit after this function returns. */ -int rhashtable_walk_init(struct rhashtable *ht, struct rhashtable_iter *iter, - gfp_t gfp) +void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) { iter->ht = ht; iter->p = NULL; iter->slot = 0; iter->skip = 0; - iter->walker = kmalloc(sizeof(*iter->walker), gfp); - if (!iter->walker) - return -ENOMEM; - spin_lock(&ht->lock); - iter->walker->tbl = + iter->walker.tbl = rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); - list_add(&iter->walker->list, &iter->walker->tbl->walkers); + list_add(&iter->walker.list, &iter->walker.tbl->walkers); spin_unlock(&ht->lock); - - return 0; } -EXPORT_SYMBOL_GPL(rhashtable_walk_init); +EXPORT_SYMBOL_GPL(rhashtable_walk_enter); /** * rhashtable_walk_exit - Free an iterator @@ -541,10 +532,9 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_init); void rhashtable_walk_exit(struct rhashtable_iter *iter) { spin_lock(&iter->ht->lock); - if (iter->walker->tbl) - list_del(&iter->walker->list); + if (iter->walker.tbl) + list_del(&iter->walker.list); spin_unlock(&iter->ht->lock); - kfree(iter->walker); } EXPORT_SYMBOL_GPL(rhashtable_walk_exit); @@ -570,12 +560,12 @@ int rhashtable_walk_start(struct rhashtable_iter *iter) rcu_read_lock(); spin_lock(&ht->lock); - if (iter->walker->tbl) - list_del(&iter->walker->list); + if (iter->walker.tbl) + list_del(&iter->walker.list); spin_unlock(&ht->lock); - if (!iter->walker->tbl) { - iter->walker->tbl = rht_dereference_rcu(ht->tbl, ht); + if (!iter->walker.tbl) { + iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); return -EAGAIN; } @@ -597,7 +587,7 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_start); */ void *rhashtable_walk_next(struct rhashtable_iter *iter) { - struct bucket_table *tbl = iter->walker->tbl; + struct bucket_table *tbl = iter->walker.tbl; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; @@ -630,8 +620,8 @@ next: /* Ensure we see any new tables. */ smp_rmb(); - iter->walker->tbl = rht_dereference_rcu(tbl->future_tbl, ht); - if (iter->walker->tbl) { + iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); + if (iter->walker.tbl) { iter->slot = 0; iter->skip = 0; return ERR_PTR(-EAGAIN); @@ -651,7 +641,7 @@ void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU) { struct rhashtable *ht; - struct bucket_table *tbl = iter->walker->tbl; + struct bucket_table *tbl = iter->walker.tbl; if (!tbl) goto out; @@ -660,9 +650,9 @@ void rhashtable_walk_stop(struct rhashtable_iter *iter) spin_lock(&ht->lock); if (tbl->rehash < tbl->size) - list_add(&iter->walker->list, &tbl->walkers); + list_add(&iter->walker.list, &tbl->walkers); else - iter->walker->tbl = NULL; + iter->walker.tbl = NULL; spin_unlock(&ht->lock); iter->p = NULL; -- 2.20.1