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authorNeilBrown <neilb@suse.com>2019-04-02 10:07:45 +1100
committerDavid S. Miller <davem@davemloft.net>2019-04-07 19:12:12 -0700
commitff302db965b57c141297911ea647d36d11fedfbe (patch)
tree4b6cdddf64de3c58e867a1886e5240c078df121b /lib/rhashtable.c
parent7a41c294c1463100fdc82a356e22e36bbaa6b0f9 (diff)
downloadlinux-ff302db965b57c141297911ea647d36d11fedfbe.tar.bz2
rhashtable: allow rht_bucket_var to return NULL.
Rather than returning a pointer to a static nulls, rht_bucket_var() now returns NULL if the bucket doesn't exist. This will make the next patch, which stores a bitlock in the bucket pointer, somewhat cleaner. This change involves introducing __rht_bucket_nested() which is like rht_bucket_nested(), but doesn't provide the static nulls, and changing rht_bucket_nested() to call this and possible provide a static nulls - as is still needed for the non-var case. Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/rhashtable.c')
-rw-r--r--lib/rhashtable.c29
1 files changed, 20 insertions, 9 deletions
diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 6c4f5c8e9baa..b28fdd560ea9 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -237,8 +237,10 @@ static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash)
goto out;
err = -ENOENT;
+ if (!pprev)
+ goto out;
- rht_for_each(entry, old_tbl, old_hash) {
+ rht_for_each_from(entry, *pprev, old_tbl, old_hash) {
err = 0;
next = rht_dereference_bucket(entry->next, old_tbl, old_hash);
@@ -496,6 +498,8 @@ static void *rhashtable_lookup_one(struct rhashtable *ht,
elasticity = RHT_ELASTICITY;
pprev = rht_bucket_var(tbl, hash);
+ if (!pprev)
+ return ERR_PTR(-ENOENT);
rht_for_each_from(head, *pprev, tbl, hash) {
struct rhlist_head *list;
struct rhlist_head *plist;
@@ -1161,11 +1165,10 @@ void rhashtable_destroy(struct rhashtable *ht)
}
EXPORT_SYMBOL_GPL(rhashtable_destroy);
-struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
- unsigned int hash)
+struct rhash_head __rcu **__rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash)
{
const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *));
- static struct rhash_head __rcu *rhnull;
unsigned int index = hash & ((1 << tbl->nest) - 1);
unsigned int size = tbl->size >> tbl->nest;
unsigned int subhash = hash;
@@ -1183,15 +1186,23 @@ struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
subhash >>= shift;
}
- if (!ntbl) {
- if (!rhnull)
- INIT_RHT_NULLS_HEAD(rhnull);
- return &rhnull;
- }
+ if (!ntbl)
+ return NULL;
return &ntbl[subhash].bucket;
}
+EXPORT_SYMBOL_GPL(__rht_bucket_nested);
+
+struct rhash_head __rcu **rht_bucket_nested(const struct bucket_table *tbl,
+ unsigned int hash)
+{
+ static struct rhash_head __rcu *rhnull;
+
+ if (!rhnull)
+ INIT_RHT_NULLS_HEAD(rhnull);
+ return __rht_bucket_nested(tbl, hash) ?: &rhnull;
+}
EXPORT_SYMBOL_GPL(rht_bucket_nested);
struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht,