diff options
Diffstat (limited to 'drivers/infiniband/core/rdma_core.c')
| -rw-r--r-- | drivers/infiniband/core/rdma_core.c | 450 |
1 files changed, 450 insertions, 0 deletions
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c new file mode 100644 index 000000000000..1cbc053add34 --- /dev/null +++ b/drivers/infiniband/core/rdma_core.c @@ -0,0 +1,450 @@ +/* + * Copyright (c) 2016, Mellanox Technologies inc. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include <linux/file.h> +#include <linux/anon_inodes.h> +#include <rdma/ib_verbs.h> +#include <rdma/uverbs_types.h> +#include <linux/rcupdate.h> +#include "uverbs.h" +#include "core_priv.h" +#include "rdma_core.h" + +void uverbs_uobject_get(struct ib_uobject *uobject) +{ + kref_get(&uobject->ref); +} + +static void uverbs_uobject_put_ref(struct kref *ref) +{ + struct ib_uobject *uobj = + container_of(ref, struct ib_uobject, ref); + + if (uobj->type->type_class->needs_kfree_rcu) + kfree_rcu(uobj, rcu); + else + kfree(uobj); +} + +void uverbs_uobject_put(struct ib_uobject *uobject) +{ + kref_put(&uobject->ref, uverbs_uobject_put_ref); +} + +static int uverbs_try_lock_object(struct ib_uobject *uobj, bool write) +{ + /* + * When a read is required, we use a positive counter. Each read + * request checks that the value != -1 and increment it. Write + * requires an exclusive access, thus we check that the counter is + * zero (nobody claimed this object) and we set it to -1. + * Releasing a read lock is done by simply decreasing the counter. + * As for writes, since only a single write is permitted, setting + * it to zero is enough for releasing it. + */ + if (!write) + return __atomic_add_unless(&uobj->usecnt, 1, -1) == -1 ? + -EBUSY : 0; + + /* lock is either WRITE or DESTROY - should be exclusive */ + return atomic_cmpxchg(&uobj->usecnt, 0, -1) == 0 ? 0 : -EBUSY; +} + +static struct ib_uobject *alloc_uobj(struct ib_ucontext *context, + const struct uverbs_obj_type *type) +{ + struct ib_uobject *uobj = kmalloc(type->obj_size, GFP_KERNEL); + + if (!uobj) + return ERR_PTR(-ENOMEM); + /* + * user_handle should be filled by the handler, + * The object is added to the list in the commit stage. + */ + uobj->context = context; + uobj->type = type; + atomic_set(&uobj->usecnt, 0); + kref_init(&uobj->ref); + + return uobj; +} + +static int idr_add_uobj(struct ib_uobject *uobj) +{ + int ret; + + idr_preload(GFP_KERNEL); + spin_lock(&uobj->context->ufile->idr_lock); + + /* + * We start with allocating an idr pointing to NULL. This represents an + * object which isn't initialized yet. We'll replace it later on with + * the real object once we commit. + */ + ret = idr_alloc(&uobj->context->ufile->idr, NULL, 0, + min_t(unsigned long, U32_MAX - 1, INT_MAX), GFP_NOWAIT); + if (ret >= 0) + uobj->id = ret; + + spin_unlock(&uobj->context->ufile->idr_lock); + idr_preload_end(); + + return ret < 0 ? ret : 0; +} + +/* + * It only removes it from the uobjects list, uverbs_uobject_put() is still + * required. + */ +static void uverbs_idr_remove_uobj(struct ib_uobject *uobj) +{ + spin_lock(&uobj->context->ufile->idr_lock); + idr_remove(&uobj->context->ufile->idr, uobj->id); + spin_unlock(&uobj->context->ufile->idr_lock); +} + +/* Returns the ib_uobject or an error. The caller should check for IS_ERR. */ +static struct ib_uobject *lookup_get_idr_uobject(const struct uverbs_obj_type *type, + struct ib_ucontext *ucontext, + int id, bool write) +{ + struct ib_uobject *uobj; + + rcu_read_lock(); + /* object won't be released as we're protected in rcu */ + uobj = idr_find(&ucontext->ufile->idr, id); + if (!uobj) { + uobj = ERR_PTR(-ENOENT); + goto free; + } + + uverbs_uobject_get(uobj); +free: + rcu_read_unlock(); + return uobj; +} + +struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type, + struct ib_ucontext *ucontext, + int id, bool write) +{ + struct ib_uobject *uobj; + int ret; + + uobj = type->type_class->lookup_get(type, ucontext, id, write); + if (IS_ERR(uobj)) + return uobj; + + if (uobj->type != type) { + ret = -EINVAL; + goto free; + } + + ret = uverbs_try_lock_object(uobj, write); + if (ret) { + WARN(ucontext->cleanup_reason, + "ib_uverbs: Trying to lookup_get while cleanup context\n"); + goto free; + } + + return uobj; +free: + uobj->type->type_class->lookup_put(uobj, write); + uverbs_uobject_put(uobj); + return ERR_PTR(ret); +} + +static struct ib_uobject *alloc_begin_idr_uobject(const struct uverbs_obj_type *type, + struct ib_ucontext *ucontext) +{ + int ret; + struct ib_uobject *uobj; + + uobj = alloc_uobj(ucontext, type); + if (IS_ERR(uobj)) + return uobj; + + ret = idr_add_uobj(uobj); + if (ret) + goto uobj_put; + + ret = ib_rdmacg_try_charge(&uobj->cg_obj, ucontext->device, + RDMACG_RESOURCE_HCA_OBJECT); + if (ret) + goto idr_remove; + + return uobj; + +idr_remove: + uverbs_idr_remove_uobj(uobj); +uobj_put: + uverbs_uobject_put(uobj); + return ERR_PTR(ret); +} + +struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type, + struct ib_ucontext *ucontext) +{ + return type->type_class->alloc_begin(type, ucontext); +} + +static void uverbs_uobject_add(struct ib_uobject *uobject) +{ + mutex_lock(&uobject->context->uobjects_lock); + list_add(&uobject->list, &uobject->context->uobjects); + mutex_unlock(&uobject->context->uobjects_lock); +} + +static int __must_check remove_commit_idr_uobject(struct ib_uobject *uobj, + enum rdma_remove_reason why) +{ + const struct uverbs_obj_idr_type *idr_type = + container_of(uobj->type, struct uverbs_obj_idr_type, + type); + int ret = idr_type->destroy_object(uobj, why); + + /* + * We can only fail gracefully if the user requested to destroy the + * object. In the rest of the cases, just remove whatever you can. + */ + if (why == RDMA_REMOVE_DESTROY && ret) + return ret; + + ib_rdmacg_uncharge(&uobj->cg_obj, uobj->context->device, + RDMACG_RESOURCE_HCA_OBJECT); + uverbs_idr_remove_uobj(uobj); + + return ret; +} + +static void lockdep_check(struct ib_uobject *uobj, bool write) +{ +#ifdef CONFIG_LOCKDEP + if (write) + WARN_ON(atomic_read(&uobj->usecnt) > 0); + else + WARN_ON(atomic_read(&uobj->usecnt) == -1); +#endif +} + +static int __must_check _rdma_remove_commit_uobject(struct ib_uobject *uobj, + enum rdma_remove_reason why, + bool lock) +{ + int ret; + struct ib_ucontext *ucontext = uobj->context; + + ret = uobj->type->type_class->remove_commit(uobj, why); + if (ret && why == RDMA_REMOVE_DESTROY) { + /* We couldn't remove the object, so just unlock the uobject */ + atomic_set(&uobj->usecnt, 0); + uobj->type->type_class->lookup_put(uobj, true); + } else { + if (lock) + mutex_lock(&ucontext->uobjects_lock); + list_del(&uobj->list); + if (lock) + mutex_unlock(&ucontext->uobjects_lock); + /* put the ref we took when we created the object */ + uverbs_uobject_put(uobj); + } + + return ret; +} + +/* This is called only for user requested DESTROY reasons */ +int __must_check rdma_remove_commit_uobject(struct ib_uobject *uobj) +{ + int ret; + struct ib_ucontext *ucontext = uobj->context; + + /* put the ref count we took at lookup_get */ + uverbs_uobject_put(uobj); + /* Cleanup is running. Calling this should have been impossible */ + if (!down_read_trylock(&ucontext->cleanup_rwsem)) { + WARN(true, "ib_uverbs: Cleanup is running while removing an uobject\n"); + return 0; + } + lockdep_check(uobj, true); + ret = _rdma_remove_commit_uobject(uobj, RDMA_REMOVE_DESTROY, true); + + up_read(&ucontext->cleanup_rwsem); + return ret; +} + +static void alloc_commit_idr_uobject(struct ib_uobject *uobj) +{ + uverbs_uobject_add(uobj); + spin_lock(&uobj->context->ufile->idr_lock); + /* + * We already allocated this IDR with a NULL object, so + * this shouldn't fail. + */ + WARN_ON(idr_replace(&uobj->context->ufile->idr, + uobj, uobj->id)); + spin_unlock(&uobj->context->ufile->idr_lock); +} + +int rdma_alloc_commit_uobject(struct ib_uobject *uobj) +{ + /* Cleanup is running. Calling this should have been impossible */ + if (!down_read_trylock(&uobj->context->cleanup_rwsem)) { + int ret; + + WARN(true, "ib_uverbs: Cleanup is running while allocating an uobject\n"); + ret = uobj->type->type_class->remove_commit(uobj, + RDMA_REMOVE_DURING_CLEANUP); + if (ret) + pr_warn("ib_uverbs: cleanup of idr object %d failed\n", + uobj->id); + return ret; + } + + uobj->type->type_class->alloc_commit(uobj); + up_read(&uobj->context->cleanup_rwsem); + + return 0; +} + +static void alloc_abort_idr_uobject(struct ib_uobject *uobj) +{ + uverbs_idr_remove_uobj(uobj); + ib_rdmacg_uncharge(&uobj->cg_obj, uobj->context->device, + RDMACG_RESOURCE_HCA_OBJECT); + uverbs_uobject_put(uobj); +} + +void rdma_alloc_abort_uobject(struct ib_uobject *uobj) +{ + uobj->type->type_class->alloc_abort(uobj); +} + +static void lookup_put_idr_uobject(struct ib_uobject *uobj, bool write) +{ +} + +void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool write) +{ + lockdep_check(uobj, write); + uobj->type->type_class->lookup_put(uobj, write); + /* + * In order to unlock an object, either decrease its usecnt for + * read access or zero it in case of write access. See + * uverbs_try_lock_object for locking schema information. + */ + if (!write) + atomic_dec(&uobj->usecnt); + else + atomic_set(&uobj->usecnt, 0); + + uverbs_uobject_put(uobj); +} + +const struct uverbs_obj_type_class uverbs_idr_class = { + .alloc_begin = alloc_begin_idr_uobject, + .lookup_get = lookup_get_idr_uobject, + .alloc_commit = alloc_commit_idr_uobject, + .alloc_abort = alloc_abort_idr_uobject, + .lookup_put = lookup_put_idr_uobject, + .remove_commit = remove_commit_idr_uobject, + /* + * When we destroy an object, we first just lock it for WRITE and + * actually DESTROY it in the finalize stage. So, the problematic + * scenario is when we just started the finalize stage of the + * destruction (nothing was executed yet). Now, the other thread + * fetched the object for READ access, but it didn't lock it yet. + * The DESTROY thread continues and starts destroying the object. + * When the other thread continue - without the RCU, it would + * access freed memory. However, the rcu_read_lock delays the free + * until the rcu_read_lock of the READ operation quits. Since the + * write lock of the object is still taken by the DESTROY flow, the + * READ operation will get -EBUSY and it'll just bail out. + */ + .needs_kfree_rcu = true, +}; + +void uverbs_cleanup_ucontext(struct ib_ucontext *ucontext, bool device_removed) +{ + enum rdma_remove_reason reason = device_removed ? + RDMA_REMOVE_DRIVER_REMOVE : RDMA_REMOVE_CLOSE; + unsigned int cur_order = 0; + + ucontext->cleanup_reason = reason; + /* + * Waits for all remove_commit and alloc_commit to finish. Logically, We + * want to hold this forever as the context is going to be destroyed, + * but we'll release it since it causes a "held lock freed" BUG message. + */ + down_write(&ucontext->cleanup_rwsem); + + while (!list_empty(&ucontext->uobjects)) { + struct ib_uobject *obj, *next_obj; + unsigned int next_order = UINT_MAX; + + /* + * This shouldn't run while executing other commands on this + * context. + */ + mutex_lock(&ucontext->uobjects_lock); + list_for_each_entry_safe(obj, next_obj, &ucontext->uobjects, + list) + if (obj->type->destroy_order == cur_order) { + int ret; + + /* + * if we hit this WARN_ON, that means we are + * racing with a lookup_get. + */ + WARN_ON(uverbs_try_lock_object(obj, true)); + ret = _rdma_remove_commit_uobject(obj, reason, + false); + if (ret) + pr_warn("ib_uverbs: failed to remove uobject id %d order %u\n", + obj->id, cur_order); + } else { + next_order = min(next_order, + obj->type->destroy_order); + } + mutex_unlock(&ucontext->uobjects_lock); + cur_order = next_order; + } + up_write(&ucontext->cleanup_rwsem); +} + +void uverbs_initialize_ucontext(struct ib_ucontext *ucontext) +{ + ucontext->cleanup_reason = 0; + mutex_init(&ucontext->uobjects_lock); + INIT_LIST_HEAD(&ucontext->uobjects); + init_rwsem(&ucontext->cleanup_rwsem); +} + |