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Commit 832ff948 authored by Jakub Kicinski's avatar Jakub Kicinski Committed by David S. Miller
Browse files

nfp: remove cpp mutex cache 



CPP mutex cache was introduced to work around the fact that the
same host could successfully acquire a lock multiple times.  It
used to collapse multiple users to the same struct nfp_cpp_mutex
and track use count.  Unfortunately it's racy.  Since we now force
all nfp_mutex_lock() callers within the host to actually succeed
at acquiring the lock we no longer need the cache, let's remove it.

Signed-off-by: default avatarJakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f1ba63ec

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c

+2 −41
Original line number Diff line number Diff line
@@ -66,10 +66,8 @@ struct nfp_cpp_resource { 
};



struct nfp_cpp_mutex {

	struct list_head list;

	struct nfp_cpp *cpp;

	int target;

	u16 usage;

	u16 depth;

	unsigned long long address;

	u32 key;
@@ -86,7 +84,6 @@ struct nfp_cpp { 


	const struct nfp_cpp_operations *op;

	struct list_head resource_list;	/* NFP CPP resource list */

	struct list_head mutex_cache;	/* Mutex cache */

	rwlock_t resource_lock;

	wait_queue_head_t waitq;
@@ -187,24 +184,6 @@ void nfp_cpp_free(struct nfp_cpp *cpp) 
{

	struct nfp_cpp_area_cache *cache, *ctmp;

	struct nfp_cpp_resource *res, *rtmp;

	struct nfp_cpp_mutex *mutex, *mtmp;



	/* There should be no mutexes in the cache at this point. */

	WARN_ON(!list_empty(&cpp->mutex_cache));

	/* .. but if there are, unlock them and complain. */

	list_for_each_entry_safe(mutex, mtmp, &cpp->mutex_cache, list) {

		dev_err(cpp->dev.parent, "Dangling mutex: @%d::0x%llx, %d locks held by %d owners\n",

			mutex->target, (unsigned long long)mutex->address,

			mutex->depth, mutex->usage);



		/* Forcing an unlock */

		mutex->depth = 1;

		nfp_cpp_mutex_unlock(mutex);



		/* Forcing a free */

		mutex->usage = 1;

		nfp_cpp_mutex_free(mutex);

	}



	/* Remove all caches */

	list_for_each_entry_safe(cache, ctmp, &cpp->area_cache_list, entry) {
@@ -1127,7 +1106,6 @@ nfp_cpp_from_operations(const struct nfp_cpp_operations *ops, 
	rwlock_init(&cpp->resource_lock);

	init_waitqueue_head(&cpp->waitq);

	lockdep_set_class(&cpp->resource_lock, &nfp_cpp_resource_lock_key);

	INIT_LIST_HEAD(&cpp->mutex_cache);

	INIT_LIST_HEAD(&cpp->resource_list);

	INIT_LIST_HEAD(&cpp->area_cache_list);

	mutex_init(&cpp->area_cache_mutex);
@@ -1536,14 +1514,6 @@ struct nfp_cpp_mutex *nfp_cpp_mutex_alloc(struct nfp_cpp *cpp, int target, 
	if (err)

		return NULL;



	/* Look for mutex on cache list */

	list_for_each_entry(mutex, &cpp->mutex_cache, list) {

		if (mutex->target == target && mutex->address == address) {

			mutex->usage++;

			return mutex;

		}

	}



	err = nfp_cpp_readl(cpp, mur, address + 4, &tmp);

	if (err < 0)

		return NULL;
@@ -1560,10 +1530,6 @@ struct nfp_cpp_mutex *nfp_cpp_mutex_alloc(struct nfp_cpp *cpp, int target, 
	mutex->address = address;

	mutex->key = key;

	mutex->depth = 0;

	mutex->usage = 1;



	/* Add mutex to cache list */

	list_add(&mutex->list, &cpp->mutex_cache);



	return mutex;

}
@@ -1574,11 +1540,6 @@ struct nfp_cpp_mutex *nfp_cpp_mutex_alloc(struct nfp_cpp *cpp, int target, 
 */

void nfp_cpp_mutex_free(struct nfp_cpp_mutex *mutex)

{

	if (--mutex->usage)

		return;



	/* Remove mutex from cache */

	list_del(&mutex->list);

	kfree(mutex);

}
@@ -1611,8 +1572,8 @@ int nfp_cpp_mutex_lock(struct nfp_cpp_mutex *mutex) 
		if (time_is_before_eq_jiffies(warn_at)) {

			warn_at = jiffies + 60 * HZ;

			dev_warn(mutex->cpp->dev.parent,

				 "Warning: waiting for NFP mutex [usage:%hd depth:%hd target:%d addr:%llx key:%08x]\n",

				 mutex->usage, mutex->depth,

				 "Warning: waiting for NFP mutex [depth:%hd target:%d addr:%llx key:%08x]\n",

				 mutex->depth,

				 mutex->target, mutex->address, mutex->key);

		}

	}