Commit a03eaec0 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller

rhashtable: Dump bucket tables on locking violation under PROVE_LOCKING

This simplifies debugging of locking violations if compiled with
CONFIG_PROVE_LOCKING.
Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2af4b529
...@@ -54,26 +54,6 @@ static spinlock_t *bucket_lock(const struct bucket_table *tbl, u32 hash) ...@@ -54,26 +54,6 @@ static spinlock_t *bucket_lock(const struct bucket_table *tbl, u32 hash)
return &tbl->locks[hash & tbl->locks_mask]; return &tbl->locks[hash & tbl->locks_mask];
} }
#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
#define ASSERT_BUCKET_LOCK(TBL, HASH) \
BUG_ON(!lockdep_rht_bucket_is_held(TBL, HASH))
#ifdef CONFIG_PROVE_LOCKING
int lockdep_rht_mutex_is_held(struct rhashtable *ht)
{
return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1;
}
EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash)
{
spinlock_t *lock = bucket_lock(tbl, hash);
return (debug_locks) ? lockdep_is_held(lock) : 1;
}
EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
#endif
static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he) static void *rht_obj(const struct rhashtable *ht, const struct rhash_head *he)
{ {
return (void *) he - ht->p.head_offset; return (void *) he - ht->p.head_offset;
...@@ -109,6 +89,77 @@ static u32 head_hashfn(const struct rhashtable *ht, ...@@ -109,6 +89,77 @@ static u32 head_hashfn(const struct rhashtable *ht,
return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he))); return rht_bucket_index(tbl, obj_raw_hashfn(ht, rht_obj(ht, he)));
} }
#ifdef CONFIG_PROVE_LOCKING
static void debug_dump_buckets(const struct rhashtable *ht,
const struct bucket_table *tbl)
{
struct rhash_head *he;
unsigned int i, hash;
for (i = 0; i < tbl->size; i++) {
pr_warn(" [Bucket %d] ", i);
rht_for_each_rcu(he, tbl, i) {
hash = head_hashfn(ht, tbl, he);
pr_cont("[hash = %#x, lock = %p] ",
hash, bucket_lock(tbl, hash));
}
pr_cont("\n");
}
}
static void debug_dump_table(struct rhashtable *ht,
const struct bucket_table *tbl,
unsigned int hash)
{
struct bucket_table *old_tbl, *future_tbl;
pr_emerg("BUG: lock for hash %#x in table %p not held\n",
hash, tbl);
rcu_read_lock();
future_tbl = rht_dereference_rcu(ht->future_tbl, ht);
old_tbl = rht_dereference_rcu(ht->tbl, ht);
if (future_tbl != old_tbl) {
pr_warn("Future table %p (size: %zd)\n",
future_tbl, future_tbl->size);
debug_dump_buckets(ht, future_tbl);
}
pr_warn("Table %p (size: %zd)\n", old_tbl, old_tbl->size);
debug_dump_buckets(ht, old_tbl);
rcu_read_unlock();
}
#define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT))
#define ASSERT_BUCKET_LOCK(HT, TBL, HASH) \
do { \
if (unlikely(!lockdep_rht_bucket_is_held(TBL, HASH))) { \
debug_dump_table(HT, TBL, HASH); \
BUG(); \
} \
} while (0)
int lockdep_rht_mutex_is_held(struct rhashtable *ht)
{
return (debug_locks) ? lockdep_is_held(&ht->mutex) : 1;
}
EXPORT_SYMBOL_GPL(lockdep_rht_mutex_is_held);
int lockdep_rht_bucket_is_held(const struct bucket_table *tbl, u32 hash)
{
spinlock_t *lock = bucket_lock(tbl, hash);
return (debug_locks) ? lockdep_is_held(lock) : 1;
}
EXPORT_SYMBOL_GPL(lockdep_rht_bucket_is_held);
#else
#define ASSERT_RHT_MUTEX(HT)
#define ASSERT_BUCKET_LOCK(HT, TBL, HASH)
#endif
static struct rhash_head __rcu **bucket_tail(struct bucket_table *tbl, u32 n) static struct rhash_head __rcu **bucket_tail(struct bucket_table *tbl, u32 n)
{ {
struct rhash_head __rcu **pprev; struct rhash_head __rcu **pprev;
...@@ -240,7 +291,7 @@ static void unlock_buckets(struct bucket_table *new_tbl, ...@@ -240,7 +291,7 @@ static void unlock_buckets(struct bucket_table *new_tbl,
* *
* Returns true if no more work needs to be performed on the bucket. * Returns true if no more work needs to be performed on the bucket.
*/ */
static bool hashtable_chain_unzip(const struct rhashtable *ht, static bool hashtable_chain_unzip(struct rhashtable *ht,
const struct bucket_table *new_tbl, const struct bucket_table *new_tbl,
struct bucket_table *old_tbl, struct bucket_table *old_tbl,
size_t old_hash) size_t old_hash)
...@@ -248,7 +299,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht, ...@@ -248,7 +299,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht,
struct rhash_head *he, *p, *next; struct rhash_head *he, *p, *next;
unsigned int new_hash, new_hash2; unsigned int new_hash, new_hash2;
ASSERT_BUCKET_LOCK(old_tbl, old_hash); ASSERT_BUCKET_LOCK(ht, old_tbl, old_hash);
/* Old bucket empty, no work needed. */ /* Old bucket empty, no work needed. */
p = rht_dereference_bucket(old_tbl->buckets[old_hash], old_tbl, p = rht_dereference_bucket(old_tbl->buckets[old_hash], old_tbl,
...@@ -257,7 +308,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht, ...@@ -257,7 +308,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht,
return false; return false;
new_hash = head_hashfn(ht, new_tbl, p); new_hash = head_hashfn(ht, new_tbl, p);
ASSERT_BUCKET_LOCK(new_tbl, new_hash); ASSERT_BUCKET_LOCK(ht, new_tbl, new_hash);
/* Advance the old bucket pointer one or more times until it /* Advance the old bucket pointer one or more times until it
* reaches a node that doesn't hash to the same bucket as the * reaches a node that doesn't hash to the same bucket as the
...@@ -265,7 +316,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht, ...@@ -265,7 +316,7 @@ static bool hashtable_chain_unzip(const struct rhashtable *ht,
*/ */
rht_for_each_continue(he, p->next, old_tbl, old_hash) { rht_for_each_continue(he, p->next, old_tbl, old_hash) {
new_hash2 = head_hashfn(ht, new_tbl, he); new_hash2 = head_hashfn(ht, new_tbl, he);
ASSERT_BUCKET_LOCK(new_tbl, new_hash2); ASSERT_BUCKET_LOCK(ht, new_tbl, new_hash2);
if (new_hash != new_hash2) if (new_hash != new_hash2)
break; break;
......
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