From 832ff9482ea44370e8a7f7e0d205be6be73d2257 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Tue, 21 Mar 2017 17:59:09 -0700 Subject: [PATCH] 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: Jakub Kicinski Signed-off-by: David S. Miller --- .../netronome/nfp/nfpcore/nfp_cppcore.c | 43 +------------------ 1 file changed, 2 insertions(+), 41 deletions(-) diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c index e2267b421af0..6337342c5b62 100644 --- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c +++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c @@ -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); } } -- GitLab