Commit 322366b8 authored by Marco Elver's avatar Marco Elver Committed by Peter Zijlstra
Browse files

rhashtable: Enable context analysis 



Enable context analysis for rhashtable, which was used as an initial
test as it contains a combination of RCU, mutex, and bit_spinlock usage.

Users of rhashtable now also benefit from annotations on the API, which
will now warn if the RCU read lock is not held where required.

Signed-off-by: default avatarMarco Elver <elver@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-33-elver@google.com
parent c3d3023f

include/linux/rhashtable.h

+13 −3
Original line number Diff line number Diff line
@@ -245,16 +245,17 @@ void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, 
void rhashtable_walk_enter(struct rhashtable *ht,

			   struct rhashtable_iter *iter);

void rhashtable_walk_exit(struct rhashtable_iter *iter);

int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU);

int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires_shared(RCU);



static inline void rhashtable_walk_start(struct rhashtable_iter *iter)

	__acquires_shared(RCU)

{

	(void)rhashtable_walk_start_check(iter);

}



void *rhashtable_walk_next(struct rhashtable_iter *iter);

void *rhashtable_walk_peek(struct rhashtable_iter *iter);

void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU);

void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases_shared(RCU);



void rhashtable_free_and_destroy(struct rhashtable *ht,

				 void (*free_fn)(void *ptr, void *arg),
@@ -325,6 +326,7 @@ static inline struct rhash_lock_head __rcu **rht_bucket_insert( 


static inline unsigned long rht_lock(struct bucket_table *tbl,

				     struct rhash_lock_head __rcu **bkt)

	__acquires(__bitlock(0, bkt))

{

	unsigned long flags;
@@ -337,6 +339,7 @@ static inline unsigned long rht_lock(struct bucket_table *tbl, 
static inline unsigned long rht_lock_nested(struct bucket_table *tbl,

					struct rhash_lock_head __rcu **bucket,

					unsigned int subclass)

	__acquires(__bitlock(0, bucket))

{

	unsigned long flags;
@@ -349,6 +352,7 @@ static inline unsigned long rht_lock_nested(struct bucket_table *tbl, 
static inline void rht_unlock(struct bucket_table *tbl,

			      struct rhash_lock_head __rcu **bkt,

			      unsigned long flags)

	__releases(__bitlock(0, bkt))

{

	lock_map_release(&tbl->dep_map);

	bit_spin_unlock(0, (unsigned long *)bkt);
@@ -424,13 +428,14 @@ static inline void rht_assign_unlock(struct bucket_table *tbl, 
				     struct rhash_lock_head __rcu **bkt,

				     struct rhash_head *obj,

				     unsigned long flags)

	__releases(__bitlock(0, bkt))

{

	if (rht_is_a_nulls(obj))

		obj = NULL;

	lock_map_release(&tbl->dep_map);

	rcu_assign_pointer(*bkt, (void *)obj);

	preempt_enable();

	__release(bitlock);

	__release(__bitlock(0, bkt));

	local_irq_restore(flags);

}
@@ -612,6 +617,7 @@ static __always_inline struct rhash_head *__rhashtable_lookup( 
	struct rhashtable *ht, const void *key,

	const struct rhashtable_params params,

	const enum rht_lookup_freq freq)

	__must_hold_shared(RCU)

{

	struct rhashtable_compare_arg arg = {

		.ht = ht,
@@ -666,6 +672,7 @@ static __always_inline struct rhash_head *__rhashtable_lookup( 
static __always_inline void *rhashtable_lookup(

	struct rhashtable *ht, const void *key,

	const struct rhashtable_params params)

	__must_hold_shared(RCU)

{

	struct rhash_head *he = __rhashtable_lookup(ht, key, params,

						    RHT_LOOKUP_NORMAL);
@@ -676,6 +683,7 @@ static __always_inline void *rhashtable_lookup( 
static __always_inline void *rhashtable_lookup_likely(

	struct rhashtable *ht, const void *key,

	const struct rhashtable_params params)

	__must_hold_shared(RCU)

{

	struct rhash_head *he = __rhashtable_lookup(ht, key, params,

						    RHT_LOOKUP_LIKELY);
@@ -727,6 +735,7 @@ static __always_inline void *rhashtable_lookup_fast( 
static __always_inline struct rhlist_head *rhltable_lookup(

	struct rhltable *hlt, const void *key,

	const struct rhashtable_params params)

	__must_hold_shared(RCU)

{

	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params,

						    RHT_LOOKUP_NORMAL);
@@ -737,6 +746,7 @@ static __always_inline struct rhlist_head *rhltable_lookup( 
static __always_inline struct rhlist_head *rhltable_lookup_likely(

	struct rhltable *hlt, const void *key,

	const struct rhashtable_params params)

	__must_hold_shared(RCU)

{

	struct rhash_head *he = __rhashtable_lookup(&hlt->ht, key, params,

						    RHT_LOOKUP_LIKELY);

lib/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -50,6 +50,8 @@ lib-$(CONFIG_MIN_HEAP) += min_heap.o 
lib-y	+= kobject.o klist.o

obj-y	+= lockref.o



CONTEXT_ANALYSIS_rhashtable.o := y



obj-y += bcd.o sort.o parser.o debug_locks.o random32.o \

	 bust_spinlocks.o kasprintf.o bitmap.o scatterlist.o \

	 list_sort.o uuid.o iov_iter.o clz_ctz.o \

lib/rhashtable.c

+3 −2
Original line number Diff line number Diff line
@@ -358,6 +358,7 @@ static int rhashtable_rehash_table(struct rhashtable *ht) 
static int rhashtable_rehash_alloc(struct rhashtable *ht,

				   struct bucket_table *old_tbl,

				   unsigned int size)

	__must_hold(&ht->mutex)

{

	struct bucket_table *new_tbl;

	int err;
@@ -392,6 +393,7 @@ static int rhashtable_rehash_alloc(struct rhashtable *ht, 
 * bucket locks or concurrent RCU protected lookups and traversals.

 */

static int rhashtable_shrink(struct rhashtable *ht)

	__must_hold(&ht->mutex)

{

	struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht);

	unsigned int nelems = atomic_read(&ht->nelems);
@@ -724,7 +726,7 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_exit); 
 * resize events and always continue.

 */

int rhashtable_walk_start_check(struct rhashtable_iter *iter)

	__acquires(RCU)

	__acquires_shared(RCU)

{

	struct rhashtable *ht = iter->ht;

	bool rhlist = ht->rhlist;
@@ -940,7 +942,6 @@ EXPORT_SYMBOL_GPL(rhashtable_walk_peek); 
 * hash table.

 */

void rhashtable_walk_stop(struct rhashtable_iter *iter)

	__releases(RCU)

{

	struct rhashtable *ht;

	struct bucket_table *tbl = iter->walker.tbl;