litmus-rt.git - The LITMUS^RT kernel.

diff options

-rw-r--r--

1 files changed, 37 insertions, 12 deletions

         struct page *page[1];
         unsigned long addr;
         int npages;
+        pfn_t pfn;
         might_sleep();
         npages = get_user_pages(current, current->mm, addr, 1, 1, 1, page,
                                 NULL);
-        if (npages != 1) {
+        if (unlikely(npages != 1)) {
-                get_page(bad_page);
+                struct vm_area_struct *vma;
-                return page_to_pfn(bad_page);
-        }
-        return page_to_pfn(page[0]);
+                vma = find_vma(current->mm, addr);
+                if (vma == NULL || addr < vma->vm_start ||
+                    !(vma->vm_flags & VM_PFNMAP)) {
+                        get_page(bad_page);
+                        return page_to_pfn(bad_page);
+                }
+                pfn = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+                BUG_ON(pfn_valid(pfn));
+        } else
+                pfn = page_to_pfn(page[0]);
+        return pfn;
 }
 EXPORT_SYMBOL_GPL(gfn_to_pfn);
 struct page *gfn_to_page(struct kvm *kvm, gfn_t gfn)
 {
-        return pfn_to_page(gfn_to_pfn(kvm, gfn));
+        pfn_t pfn;
+        pfn = gfn_to_pfn(kvm, gfn);
+        if (pfn_valid(pfn))
+                return pfn_to_page(pfn);
+        WARN_ON(!pfn_valid(pfn));
+        get_page(bad_page);
+        return bad_page;
 }
 EXPORT_SYMBOL_GPL(gfn_to_page);
 void kvm_release_pfn_clean(pfn_t pfn)
 {
-        put_page(pfn_to_page(pfn));
+        if (pfn_valid(pfn))
+                put_page(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_release_pfn_clean);
 void kvm_set_pfn_dirty(pfn_t pfn)
 {
-        struct page *page = pfn_to_page(pfn);
+        if (pfn_valid(pfn)) {
-        if (!PageReserved(page))
+                struct page *page = pfn_to_page(pfn);
-                SetPageDirty(page);
+                if (!PageReserved(page))
+                        SetPageDirty(page);
+        }
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_dirty);
 void kvm_set_pfn_accessed(pfn_t pfn)
 {
-        mark_page_accessed(pfn_to_page(pfn));
+        if (pfn_valid(pfn))
+                mark_page_accessed(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_set_pfn_accessed);
 void kvm_get_pfn(pfn_t pfn)
 {
-        get_page(pfn_to_page(pfn));
+        if (pfn_valid(pfn))
+                get_page(pfn_to_page(pfn));
 }
 EXPORT_SYMBOL_GPL(kvm_get_pfn);

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/* * Resizable, Scalable, Concurrent Hash Table * * Copyright (c) 2015 Herbert Xu <herbert@gondor.apana.org.au> * Copyright (c) 2014-2015 Thomas Graf <tgraf@suug.ch> * Copyright (c) 2008-2014 Patrick McHardy <kaber@trash.net> * * Code partially derived from nft_hash * Rewritten with rehash code from br_multicast plus single list * pointer as suggested by Josh Triplett * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <linux/atomic.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/log2.h> #include <linux/sched.h> #include <linux/rculist.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/mm.h> #include <linux/jhash.h> #include <linux/random.h> #include <linux/rhashtable.h> #include <linux/err.h> #include <linux/export.h> #define HASH_DEFAULT_SIZE 64UL #define HASH_MIN_SIZE 4U #define BUCKET_LOCKS_PER_CPU 32UL union nested_table { union nested_table __rcu *table; struct rhash_head __rcu *bucket; }; static u32 head_hashfn(struct rhashtable *ht, const struct bucket_table *tbl, const struct rhash_head *he) { return rht_head_hashfn(ht, tbl, he, ht->p); } #ifdef CONFIG_PROVE_LOCKING #define ASSERT_RHT_MUTEX(HT) BUG_ON(!lockdep_rht_mutex_is_held(HT)) 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 = rht_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) #endif static void nested_table_free(union nested_table *ntbl, unsigned int size) { const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); const unsigned int len = 1 << shift; unsigned int i; ntbl = rcu_dereference_raw(ntbl->table); if (!ntbl) return; if (size > len) { size >>= shift; for (i = 0; i < len; i++) nested_table_free(ntbl + i, size); } kfree(ntbl); } static void nested_bucket_table_free(const struct bucket_table *tbl) { unsigned int size = tbl->size >> tbl->nest; unsigned int len = 1 << tbl->nest; union nested_table *ntbl; unsigned int i; ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); for (i = 0; i < len; i++) nested_table_free(ntbl + i, size); kfree(ntbl); } static void bucket_table_free(const struct bucket_table *tbl) { if (tbl->nest) nested_bucket_table_free(tbl); free_bucket_spinlocks(tbl->locks); kvfree(tbl); } static void bucket_table_free_rcu(struct rcu_head *head) { bucket_table_free(container_of(head, struct bucket_table, rcu)); } static union nested_table *nested_table_alloc(struct rhashtable *ht, union nested_table __rcu **prev, unsigned int shifted, unsigned int nhash) { union nested_table *ntbl; int i; ntbl = rcu_dereference(*prev); if (ntbl) return ntbl; ntbl = kzalloc(PAGE_SIZE, GFP_ATOMIC); if (ntbl && shifted) { for (i = 0; i < PAGE_SIZE / sizeof(ntbl[0].bucket); i++) INIT_RHT_NULLS_HEAD(ntbl[i].bucket, ht, (i << shifted) | nhash); } rcu_assign_pointer(*prev, ntbl); return ntbl; } static struct bucket_table *nested_bucket_table_alloc(struct rhashtable *ht, size_t nbuckets, gfp_t gfp) { const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); struct bucket_table *tbl; size_t size; if (nbuckets < (1 << (shift + 1))) return NULL; size = sizeof(*tbl) + sizeof(tbl->buckets[0]); tbl = kzalloc(size, gfp); if (!tbl) return NULL; if (!nested_table_alloc(ht, (union nested_table __rcu **)tbl->buckets, 0, 0)) { kfree(tbl); return NULL; } tbl->nest = (ilog2(nbuckets) - 1) % shift + 1; return tbl; } static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, size_t nbuckets, gfp_t gfp) { struct bucket_table *tbl = NULL; size_t size, max_locks; int i; size = sizeof(*tbl) + nbuckets * sizeof(tbl->buckets[0]); if (gfp != GFP_KERNEL) tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY); else tbl = kvzalloc(size, gfp); size = nbuckets; if (tbl == NULL && gfp != GFP_KERNEL) { tbl = nested_bucket_table_alloc(ht, nbuckets, gfp); nbuckets = 0; } if (tbl == NULL) return NULL; tbl->size = size; max_locks = size >> 1; if (tbl->nest) max_locks = min_t(size_t, max_locks, 1U << tbl->nest); if (alloc_bucket_spinlocks(&tbl->locks, &tbl->locks_mask, max_locks, ht->p.locks_mul, gfp) < 0) { bucket_table_free(tbl); return NULL; } INIT_LIST_HEAD(&tbl->walkers); tbl->hash_rnd = get_random_u32(); for (i = 0; i < nbuckets; i++) INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i); return tbl; } static struct bucket_table *rhashtable_last_table(struct rhashtable *ht, struct bucket_table *tbl) { struct bucket_table *new_tbl; do { new_tbl = tbl; tbl = rht_dereference_rcu(tbl->future_tbl, ht); } while (tbl); return new_tbl; } static int rhashtable_rehash_one(struct rhashtable *ht, unsigned int old_hash) { struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); struct bucket_table *new_tbl = rhashtable_last_table(ht, rht_dereference_rcu(old_tbl->future_tbl, ht)); struct rhash_head __rcu **pprev = rht_bucket_var(old_tbl, old_hash); int err = -EAGAIN; struct rhash_head *head, *next, *entry; spinlock_t *new_bucket_lock; unsigned int new_hash; if (new_tbl->nest) goto out; err = -ENOENT; rht_for_each(entry, old_tbl, old_hash) { err = 0; next = rht_dereference_bucket(entry->next, old_tbl, old_hash); if (rht_is_a_nulls(next)) break; pprev = &entry->next; } if (err) goto out; new_hash = head_hashfn(ht, new_tbl, entry); new_bucket_lock = rht_bucket_lock(new_tbl, new_hash); spin_lock_nested(new_bucket_lock, SINGLE_DEPTH_NESTING); head = rht_dereference_bucket(new_tbl->buckets[new_hash], new_tbl, new_hash); RCU_INIT_POINTER(entry->next, head); rcu_assign_pointer(new_tbl->buckets[new_hash], entry); spin_unlock(new_bucket_lock); rcu_assign_pointer(*pprev, next); out: return err; } static int rhashtable_rehash_chain(struct rhashtable *ht, unsigned int old_hash) { struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); spinlock_t *old_bucket_lock; int err; old_bucket_lock = rht_bucket_lock(old_tbl, old_hash); spin_lock_bh(old_bucket_lock); while (!(err = rhashtable_rehash_one(ht, old_hash))) ; if (err == -ENOENT) { old_tbl->rehash++; err = 0; } spin_unlock_bh(old_bucket_lock); return err; } static int rhashtable_rehash_attach(struct rhashtable *ht, struct bucket_table *old_tbl, struct bucket_table *new_tbl) { /* Protect future_tbl using the first bucket lock. */ spin_lock_bh(old_tbl->locks); /* Did somebody beat us to it? */ if (rcu_access_pointer(old_tbl->future_tbl)) { spin_unlock_bh(old_tbl->locks); return -EEXIST; } /* Make insertions go into the new, empty table right away. Deletions * and lookups will be attempted in both tables until we synchronize. */ rcu_assign_pointer(old_tbl->future_tbl, new_tbl); spin_unlock_bh(old_tbl->locks); return 0; } static int rhashtable_rehash_table(struct rhashtable *ht) { struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); struct bucket_table *new_tbl; struct rhashtable_walker *walker; unsigned int old_hash; int err; new_tbl = rht_dereference(old_tbl->future_tbl, ht); if (!new_tbl) return 0; for (old_hash = 0; old_hash < old_tbl->size; old_hash++) { err = rhashtable_rehash_chain(ht, old_hash); if (err) return err; } /* Publish the new table pointer. */ rcu_assign_pointer(ht->tbl, new_tbl); spin_lock(&ht->lock); list_for_each_entry(walker, &old_tbl->walkers, list) walker->tbl = NULL; spin_unlock(&ht->lock); /* Wait for readers. All new readers will see the new * table, and thus no references to the old table will * remain. */ call_rcu(&old_tbl->rcu, bucket_table_free_rcu); return rht_dereference(new_tbl->future_tbl, ht) ? -EAGAIN : 0; } static int rhashtable_rehash_alloc(struct rhashtable *ht, struct bucket_table *old_tbl, unsigned int size) { struct bucket_table *new_tbl; int err; ASSERT_RHT_MUTEX(ht); new_tbl = bucket_table_alloc(ht, size, GFP_KERNEL); if (new_tbl == NULL) return -ENOMEM; err = rhashtable_rehash_attach(ht, old_tbl, new_tbl); if (err) bucket_table_free(new_tbl); return err; } /** * rhashtable_shrink - Shrink hash table while allowing concurrent lookups * @ht: the hash table to shrink * * This function shrinks the hash table to fit, i.e., the smallest * size would not cause it to expand right away automatically. * * The caller must ensure that no concurrent resizing occurs by holding * ht->mutex. * * The caller must ensure that no concurrent table mutations take place. * It is however valid to have concurrent lookups if they are RCU protected. * * It is valid to have concurrent insertions and deletions protected by per * bucket locks or concurrent RCU protected lookups and traversals. */ static int rhashtable_shrink(struct rhashtable *ht) { struct bucket_table *old_tbl = rht_dereference(ht->tbl, ht); unsigned int nelems = atomic_read(&ht->nelems); unsigned int size = 0; if (nelems) size = roundup_pow_of_two(nelems * 3 / 2); if (size < ht->p.min_size) size = ht->p.min_size; if (old_tbl->size <= size) return 0; if (rht_dereference(old_tbl->future_tbl, ht)) return -EEXIST; return rhashtable_rehash_alloc(ht, old_tbl, size); } static void rht_deferred_worker(struct work_struct *work) { struct rhashtable *ht; struct bucket_table *tbl; int err = 0; ht = container_of(work, struct rhashtable, run_work); mutex_lock(&ht->mutex); tbl = rht_dereference(ht->tbl, ht); tbl = rhashtable_last_table(ht, tbl); if (rht_grow_above_75(ht, tbl)) err = rhashtable_rehash_alloc(ht, tbl, tbl->size * 2); else if (ht->p.automatic_shrinking && rht_shrink_below_30(ht, tbl)) err = rhashtable_shrink(ht); else if (tbl->nest) err = rhashtable_rehash_alloc(ht, tbl, tbl->size); if (!err) err = rhashtable_rehash_table(ht); mutex_unlock(&ht->mutex); if (err) schedule_work(&ht->run_work); } static int rhashtable_insert_rehash(struct rhashtable *ht, struct bucket_table *tbl) { struct bucket_table *old_tbl; struct bucket_table *new_tbl; unsigned int size; int err; old_tbl = rht_dereference_rcu(ht->tbl, ht); size = tbl->size; err = -EBUSY; if (rht_grow_above_75(ht, tbl)) size *= 2; /* Do not schedule more than one rehash */ else if (old_tbl != tbl) goto fail; err = -ENOMEM; new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC); if (new_tbl == NULL) goto fail; err = rhashtable_rehash_attach(ht, tbl, new_tbl); if (err) { bucket_table_free(new_tbl); if (err == -EEXIST) err = 0; } else schedule_work(&ht->run_work); return err; fail: /* Do not fail the insert if someone else did a rehash. */ if (likely(rcu_dereference_raw(tbl->future_tbl))) return 0; /* Schedule async rehash to retry allocation in process context. */ if (err == -ENOMEM) schedule_work(&ht->run_work); return err; } static void *rhashtable_lookup_one(struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash, const void *key, struct rhash_head *obj) { struct rhashtable_compare_arg arg = { .ht = ht, .key = key, }; struct rhash_head __rcu **pprev; struct rhash_head *head; int elasticity; elasticity = RHT_ELASTICITY; pprev = rht_bucket_var(tbl, hash); rht_for_each_continue(head, *pprev, tbl, hash) { struct rhlist_head *list; struct rhlist_head *plist; elasticity--; if (!key || (ht->p.obj_cmpfn ? ht->p.obj_cmpfn(&arg, rht_obj(ht, head)) : rhashtable_compare(&arg, rht_obj(ht, head)))) continue; if (!ht->rhlist) return rht_obj(ht, head); list = container_of(obj, struct rhlist_head, rhead); plist = container_of(head, struct rhlist_head, rhead); RCU_INIT_POINTER(list->next, plist); head = rht_dereference_bucket(head->next, tbl, hash); RCU_INIT_POINTER(list->rhead.next, head); rcu_assign_pointer(*pprev, obj); return NULL; } if (elasticity <= 0) return ERR_PTR(-EAGAIN); return ERR_PTR(-ENOENT); } static struct bucket_table *rhashtable_insert_one(struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash, struct rhash_head *obj, void *data) { struct rhash_head __rcu **pprev; struct bucket_table *new_tbl; struct rhash_head *head; if (!IS_ERR_OR_NULL(data)) return ERR_PTR(-EEXIST); if (PTR_ERR(data) != -EAGAIN && PTR_ERR(data) != -ENOENT) return ERR_CAST(data); new_tbl = rcu_dereference(tbl->future_tbl); if (new_tbl) return new_tbl; if (PTR_ERR(data) != -ENOENT) return ERR_CAST(data); if (unlikely(rht_grow_above_max(ht, tbl))) return ERR_PTR(-E2BIG); if (unlikely(rht_grow_above_100(ht, tbl))) return ERR_PTR(-EAGAIN); pprev = rht_bucket_insert(ht, tbl, hash); if (!pprev) return ERR_PTR(-ENOMEM); head = rht_dereference_bucket(*pprev, tbl, hash); RCU_INIT_POINTER(obj->next, head); if (ht->rhlist) { struct rhlist_head *list; list = container_of(obj, struct rhlist_head, rhead); RCU_INIT_POINTER(list->next, NULL); } rcu_assign_pointer(*pprev, obj); atomic_inc(&ht->nelems); if (rht_grow_above_75(ht, tbl)) schedule_work(&ht->run_work); return NULL; } static void *rhashtable_try_insert(struct rhashtable *ht, const void *key, struct rhash_head *obj) { struct bucket_table *new_tbl; struct bucket_table *tbl; unsigned int hash; spinlock_t *lock; void *data; tbl = rcu_dereference(ht->tbl); /* All insertions must grab the oldest table containing * the hashed bucket that is yet to be rehashed. */ for (;;) { hash = rht_head_hashfn(ht, tbl, obj, ht->p); lock = rht_bucket_lock(tbl, hash); spin_lock_bh(lock); if (tbl->rehash <= hash) break; spin_unlock_bh(lock); tbl = rcu_dereference(tbl->future_tbl); } data = rhashtable_lookup_one(ht, tbl, hash, key, obj); new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); if (PTR_ERR(new_tbl) != -EEXIST) data = ERR_CAST(new_tbl); while (!IS_ERR_OR_NULL(new_tbl)) { tbl = new_tbl; hash = rht_head_hashfn(ht, tbl, obj, ht->p); spin_lock_nested(rht_bucket_lock(tbl, hash), SINGLE_DEPTH_NESTING); data = rhashtable_lookup_one(ht, tbl, hash, key, obj); new_tbl = rhashtable_insert_one(ht, tbl, hash, obj, data); if (PTR_ERR(new_tbl) != -EEXIST) data = ERR_CAST(new_tbl); spin_unlock(rht_bucket_lock(tbl, hash)); } spin_unlock_bh(lock); if (PTR_ERR(data) == -EAGAIN) data = ERR_PTR(rhashtable_insert_rehash(ht, tbl) ?: -EAGAIN); return data; } void *rhashtable_insert_slow(struct rhashtable *ht, const void *key, struct rhash_head *obj) { void *data; do { rcu_read_lock(); data = rhashtable_try_insert(ht, key, obj); rcu_read_unlock(); } while (PTR_ERR(data) == -EAGAIN); return data; } EXPORT_SYMBOL_GPL(rhashtable_insert_slow); /** * rhashtable_walk_enter - Initialise an iterator * @ht: Table to walk over * @iter: Hash table Iterator * * This function prepares a hash table walk. * * Note that if you restart a walk after rhashtable_walk_stop you * may see the same object twice. Also, you may miss objects if * there are removals in between rhashtable_walk_stop and the next * call to rhashtable_walk_start. * * For a completely stable walk you should construct your own data * structure outside the hash table. * * This function may sleep so you must not call it from interrupt * context or with spin locks held. * * You must call rhashtable_walk_exit after this function returns. */ void rhashtable_walk_enter(struct rhashtable *ht, struct rhashtable_iter *iter) { iter->ht = ht; iter->p = NULL; iter->slot = 0; iter->skip = 0; iter->end_of_table = 0; spin_lock(&ht->lock); iter->walker.tbl = rcu_dereference_protected(ht->tbl, lockdep_is_held(&ht->lock)); list_add(&iter->walker.list, &iter->walker.tbl->walkers); spin_unlock(&ht->lock); } EXPORT_SYMBOL_GPL(rhashtable_walk_enter); /** * rhashtable_walk_exit - Free an iterator * @iter: Hash table Iterator * * This function frees resources allocated by rhashtable_walk_init. */ void rhashtable_walk_exit(struct rhashtable_iter *iter) { spin_lock(&iter->ht->lock); if (iter->walker.tbl) list_del(&iter->walker.list); spin_unlock(&iter->ht->lock); } EXPORT_SYMBOL_GPL(rhashtable_walk_exit); /** * rhashtable_walk_start_check - Start a hash table walk * @iter: Hash table iterator * * Start a hash table walk at the current iterator position. Note that we take * the RCU lock in all cases including when we return an error. So you must * always call rhashtable_walk_stop to clean up. * * Returns zero if successful. * * Returns -EAGAIN if resize event occured. Note that the iterator * will rewind back to the beginning and you may use it immediately * by calling rhashtable_walk_next. * * rhashtable_walk_start is defined as an inline variant that returns * void. This is preferred in cases where the caller would ignore * resize events and always continue. */ int rhashtable_walk_start_check(struct rhashtable_iter *iter) __acquires(RCU) { struct rhashtable *ht = iter->ht; rcu_read_lock(); spin_lock(&ht->lock); if (iter->walker.tbl) list_del(&iter->walker.list); spin_unlock(&ht->lock); if (!iter->walker.tbl && !iter->end_of_table) { iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); return -EAGAIN; } return 0; } EXPORT_SYMBOL_GPL(rhashtable_walk_start_check); /** * __rhashtable_walk_find_next - Find the next element in a table (or the first * one in case of a new walk). * * @iter: Hash table iterator * * Returns the found object or NULL when the end of the table is reached. * * Returns -EAGAIN if resize event occurred. */ static void *__rhashtable_walk_find_next(struct rhashtable_iter *iter) { struct bucket_table *tbl = iter->walker.tbl; struct rhlist_head *list = iter->list; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; bool rhlist = ht->rhlist; if (!tbl) return NULL; for (; iter->slot < tbl->size; iter->slot++) { int skip = iter->skip; rht_for_each_rcu(p, tbl, iter->slot) { if (rhlist) { list = container_of(p, struct rhlist_head, rhead); do { if (!skip) goto next; skip--; list = rcu_dereference(list->next); } while (list); continue; } if (!skip) break; skip--; } next: if (!rht_is_a_nulls(p)) { iter->skip++; iter->p = p; iter->list = list; return rht_obj(ht, rhlist ? &list->rhead : p); } iter->skip = 0; } iter->p = NULL; /* Ensure we see any new tables. */ smp_rmb(); iter->walker.tbl = rht_dereference_rcu(tbl->future_tbl, ht); if (iter->walker.tbl) { iter->slot = 0; iter->skip = 0; return ERR_PTR(-EAGAIN); } else { iter->end_of_table = true; } return NULL; } /** * rhashtable_walk_next - Return the next object and advance the iterator * @iter: Hash table iterator * * Note that you must call rhashtable_walk_stop when you are finished * with the walk. * * Returns the next object or NULL when the end of the table is reached. * * Returns -EAGAIN if resize event occurred. Note that the iterator * will rewind back to the beginning and you may continue to use it. */ void *rhashtable_walk_next(struct rhashtable_iter *iter) { struct rhlist_head *list = iter->list; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; bool rhlist = ht->rhlist; if (p) { if (!rhlist || !(list = rcu_dereference(list->next))) { p = rcu_dereference(p->next); list = container_of(p, struct rhlist_head, rhead); } if (!rht_is_a_nulls(p)) { iter->skip++; iter->p = p; iter->list = list; return rht_obj(ht, rhlist ? &list->rhead : p); } /* At the end of this slot, switch to next one and then find * next entry from that point. */ iter->skip = 0; iter->slot++; } return __rhashtable_walk_find_next(iter); } EXPORT_SYMBOL_GPL(rhashtable_walk_next); /** * rhashtable_walk_peek - Return the next object but don't advance the iterator * @iter: Hash table iterator * * Returns the next object or NULL when the end of the table is reached. * * Returns -EAGAIN if resize event occurred. Note that the iterator * will rewind back to the beginning and you may continue to use it. */ void *rhashtable_walk_peek(struct rhashtable_iter *iter) { struct rhlist_head *list = iter->list; struct rhashtable *ht = iter->ht; struct rhash_head *p = iter->p; if (p) return rht_obj(ht, ht->rhlist ? &list->rhead : p); /* No object found in current iter, find next one in the table. */ if (iter->skip) { /* A nonzero skip value points to the next entry in the table * beyond that last one that was found. Decrement skip so * we find the current value. __rhashtable_walk_find_next * will restore the original value of skip assuming that * the table hasn't changed. */ iter->skip--; } return __rhashtable_walk_find_next(iter); } EXPORT_SYMBOL_GPL(rhashtable_walk_peek); /** * rhashtable_walk_stop - Finish a hash table walk * @iter: Hash table iterator * * Finish a hash table walk. Does not reset the iterator to the start of the * hash table. */ void rhashtable_walk_stop(struct rhashtable_iter *iter) __releases(RCU) { struct rhashtable *ht; struct bucket_table *tbl = iter->walker.tbl; if (!tbl) goto out; ht = iter->ht; spin_lock(&ht->lock); if (tbl->rehash < tbl->size) list_add(&iter->walker.list, &tbl->walkers); else iter->walker.tbl = NULL; spin_unlock(&ht->lock); iter->p = NULL; out: rcu_read_unlock(); } EXPORT_SYMBOL_GPL(rhashtable_walk_stop); static size_t rounded_hashtable_size(const struct rhashtable_params *params) { return max(roundup_pow_of_two(params->nelem_hint * 4 / 3), (unsigned long)params->min_size); } static u32 rhashtable_jhash2(const void *key, u32 length, u32 seed) { return jhash2(key, length, seed); } /** * rhashtable_init - initialize a new hash table * @ht: hash table to be initialized * @params: configuration parameters * * Initializes a new hash table based on the provided configuration * parameters. A table can be configured either with a variable or * fixed length key: * * Configuration Example 1: Fixed length keys * struct test_obj { * int key; * void * my_member; * struct rhash_head node; * }; * * struct rhashtable_params params = { * .head_offset = offsetof(struct test_obj, node), * .key_offset = offsetof(struct test_obj, key), * .key_len = sizeof(int), * .hashfn = jhash, * .nulls_base = (1U << RHT_BASE_SHIFT), * }; * * Configuration Example 2: Variable length keys * struct test_obj { * [...] * struct rhash_head node; * }; * * u32 my_hash_fn(const void *data, u32 len, u32 seed) * { * struct test_obj *obj = data; * * return [... hash ...]; * } * * struct rhashtable_params params = { * .head_offset = offsetof(struct test_obj, node), * .hashfn = jhash, * .obj_hashfn = my_hash_fn, * }; */ int rhashtable_init(struct rhashtable *ht, const struct rhashtable_params *params) { struct bucket_table *tbl; size_t size; size = HASH_DEFAULT_SIZE; if ((!params->key_len && !params->obj_hashfn) || (params->obj_hashfn && !params->obj_cmpfn)) return -EINVAL; if (params->nulls_base && params->nulls_base < (1U << RHT_BASE_SHIFT)) return -EINVAL; memset(ht, 0, sizeof(*ht)); mutex_init(&ht->mutex); spin_lock_init(&ht->lock); memcpy(&ht->p, params, sizeof(*params)); if (params->min_size) ht->p.min_size = roundup_pow_of_two(params->min_size); /* Cap total entries at 2^31 to avoid nelems overflow. */ ht->max_elems = 1u << 31; if (params->max_size) { ht->p.max_size = rounddown_pow_of_two(params->max_size); if (ht->p.max_size < ht->max_elems / 2) ht->max_elems = ht->p.max_size * 2; } ht->p.min_size = max_t(u16, ht->p.min_size, HASH_MIN_SIZE); if (params->nelem_hint) size = rounded_hashtable_size(&ht->p); if (params->locks_mul) ht->p.locks_mul = roundup_pow_of_two(params->locks_mul); else ht->p.locks_mul = BUCKET_LOCKS_PER_CPU; ht->key_len = ht->p.key_len; if (!params->hashfn) { ht->p.hashfn = jhash; if (!(ht->key_len & (sizeof(u32) - 1))) { ht->key_len /= sizeof(u32); ht->p.hashfn = rhashtable_jhash2; } } tbl = bucket_table_alloc(ht, size, GFP_KERNEL); if (tbl == NULL) return -ENOMEM; atomic_set(&ht->nelems, 0); RCU_INIT_POINTER(ht->tbl, tbl); INIT_WORK(&ht->run_work, rht_deferred_worker); return 0; } EXPORT_SYMBOL_GPL(rhashtable_init); /** * rhltable_init - initialize a new hash list table * @hlt: hash list table to be initialized * @params: configuration parameters * * Initializes a new hash list table. * * See documentation for rhashtable_init. */ int rhltable_init(struct rhltable *hlt, const struct rhashtable_params *params) { int err; /* No rhlist NULLs marking for now. */ if (params->nulls_base) return -EINVAL; err = rhashtable_init(&hlt->ht, params); hlt->ht.rhlist = true; return err; } EXPORT_SYMBOL_GPL(rhltable_init); static void rhashtable_free_one(struct rhashtable *ht, struct rhash_head *obj, void (*free_fn)(void *ptr, void *arg), void *arg) { struct rhlist_head *list; if (!ht->rhlist) { free_fn(rht_obj(ht, obj), arg); return; } list = container_of(obj, struct rhlist_head, rhead); do { obj = &list->rhead; list = rht_dereference(list->next, ht); free_fn(rht_obj(ht, obj), arg); } while (list); } /** * rhashtable_free_and_destroy - free elements and destroy hash table * @ht: the hash table to destroy * @free_fn: callback to release resources of element * @arg: pointer passed to free_fn * * Stops an eventual async resize. If defined, invokes free_fn for each * element to releasal resources. Please note that RCU protected * readers may still be accessing the elements. Releasing of resources * must occur in a compatible manner. Then frees the bucket array. * * This function will eventually sleep to wait for an async resize * to complete. The caller is responsible that no further write operations * occurs in parallel. */ void rhashtable_free_and_destroy(struct rhashtable *ht, void (*free_fn)(void *ptr, void *arg), void *arg) { struct bucket_table *tbl; unsigned int i; cancel_work_sync(&ht->run_work); mutex_lock(&ht->mutex); tbl = rht_dereference(ht->tbl, ht); if (free_fn) { for (i = 0; i < tbl->size; i++) { struct rhash_head *pos, *next; for (pos = rht_dereference(*rht_bucket(tbl, i), ht), next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL; !rht_is_a_nulls(pos); pos = next, next = !rht_is_a_nulls(pos) ? rht_dereference(pos->next, ht) : NULL) rhashtable_free_one(ht, pos, free_fn, arg); } } bucket_table_free(tbl); mutex_unlock(&ht->mutex); } EXPORT_SYMBOL_GPL(rhashtable_free_and_destroy); void rhashtable_destroy(struct rhashtable *ht) { return rhashtable_free_and_destroy(ht, NULL, NULL); } EXPORT_SYMBOL_GPL(rhashtable_destroy); 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 = (struct rhash_head __rcu *)NULLS_MARKER(0); unsigned int index = hash & ((1 << tbl->nest) - 1); unsigned int size = tbl->size >> tbl->nest; unsigned int subhash = hash; union nested_table *ntbl; ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); subhash >>= tbl->nest; while (ntbl && size > (1 << shift)) { index = subhash & ((1 << shift) - 1); ntbl = rht_dereference_bucket_rcu(ntbl[index].table, tbl, hash); size >>= shift; subhash >>= shift; } if (!ntbl) return &rhnull; return &ntbl[subhash].bucket; } EXPORT_SYMBOL_GPL(rht_bucket_nested); struct rhash_head __rcu **rht_bucket_nested_insert(struct rhashtable *ht, struct bucket_table *tbl, unsigned int hash) { const unsigned int shift = PAGE_SHIFT - ilog2(sizeof(void *)); unsigned int index = hash & ((1 << tbl->nest) - 1); unsigned int size = tbl->size >> tbl->nest; union nested_table *ntbl; unsigned int shifted; unsigned int nhash; ntbl = (union nested_table *)rcu_dereference_raw(tbl->buckets[0]); hash >>= tbl->nest; nhash = index; shifted = tbl->nest; ntbl = nested_table_alloc(ht, &ntbl[index].table, size <= (1 << shift) ? shifted : 0, nhash); while (ntbl && size > (1 << shift)) { index = hash & ((1 << shift) - 1); size >>= shift; hash >>= shift; nhash |= index << shifted; shifted += shift; ntbl = nested_table_alloc(ht, &ntbl[index].table, size <= (1 << shift) ? shifted : 0, nhash); } if (!ntbl) return NULL; return &ntbl[hash].bucket; } EXPORT_SYMBOL_GPL(rht_bucket_nested_insert);


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