diff options
| -rw-r--r-- | drivers/infiniband/core/rdma_core.c | 60 | ||||
| -rw-r--r-- | include/rdma/uverbs_types.h | 33 |
2 files changed, 48 insertions, 45 deletions
diff --git a/drivers/infiniband/core/rdma_core.c b/drivers/infiniband/core/rdma_core.c index e5bdf7f67574..88d1e596f910 100644 --- a/drivers/infiniband/core/rdma_core.c +++ b/drivers/infiniband/core/rdma_core.c @@ -44,7 +44,7 @@ void uverbs_uobject_get(struct ib_uobject *uobject) kref_get(&uobject->ref); } -static void uverbs_uobject_put_ref(struct kref *ref) +static void uverbs_uobject_free(struct kref *ref) { struct ib_uobject *uobj = container_of(ref, struct ib_uobject, ref); @@ -57,21 +57,23 @@ static void uverbs_uobject_put_ref(struct kref *ref) void uverbs_uobject_put(struct ib_uobject *uobject) { - kref_put(&uobject->ref, uverbs_uobject_put_ref); + kref_put(&uobject->ref, uverbs_uobject_free); } -static int uverbs_try_lock_object(struct ib_uobject *uobj, bool write) +static int uverbs_try_lock_object(struct ib_uobject *uobj, bool exclusive) { /* - * 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. + * When a shared access is required, we use a positive counter. Each + * shared access request checks that the value != -1 and increment it. + * Exclusive access is required for operations like write or destroy. + * In exclusive access mode, we check that the counter is zero (nobody + * claimed this object) and we set it to -1. Releasing a shared access + * lock is done simply by decreasing the counter. As for exclusive + * access locks, since only a single one of them is is allowed + * concurrently, setting the counter to zero is enough for releasing + * this lock. */ - if (!write) + if (!exclusive) return __atomic_add_unless(&uobj->usecnt, 1, -1) == -1 ? -EBUSY : 0; @@ -135,7 +137,7 @@ static void uverbs_idr_remove_uobj(struct ib_uobject *uobj) /* 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) + int id, bool exclusive) { struct ib_uobject *uobj; @@ -155,14 +157,14 @@ free: static struct ib_uobject *lookup_get_fd_uobject(const struct uverbs_obj_type *type, struct ib_ucontext *ucontext, - int id, bool write) + int id, bool exclusive) { struct file *f; struct ib_uobject *uobject; const struct uverbs_obj_fd_type *fd_type = container_of(type, struct uverbs_obj_fd_type, type); - if (write) + if (exclusive) return ERR_PTR(-EOPNOTSUPP); f = fget(id); @@ -186,12 +188,12 @@ static struct ib_uobject *lookup_get_fd_uobject(const struct uverbs_obj_type *ty struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type, struct ib_ucontext *ucontext, - int id, bool write) + int id, bool exclusive) { struct ib_uobject *uobj; int ret; - uobj = type->type_class->lookup_get(type, ucontext, id, write); + uobj = type->type_class->lookup_get(type, ucontext, id, exclusive); if (IS_ERR(uobj)) return uobj; @@ -200,7 +202,7 @@ struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type, goto free; } - ret = uverbs_try_lock_object(uobj, write); + ret = uverbs_try_lock_object(uobj, exclusive); if (ret) { WARN(ucontext->cleanup_reason, "ib_uverbs: Trying to lookup_get while cleanup context\n"); @@ -209,7 +211,7 @@ struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type, return uobj; free: - uobj->type->type_class->lookup_put(uobj, write); + uobj->type->type_class->lookup_put(uobj, exclusive); uverbs_uobject_put(uobj); return ERR_PTR(ret); } @@ -350,10 +352,10 @@ static int __must_check remove_commit_fd_uobject(struct ib_uobject *uobj, return ret; } -static void lockdep_check(struct ib_uobject *uobj, bool write) +static void lockdep_check(struct ib_uobject *uobj, bool exclusive) { #ifdef CONFIG_LOCKDEP - if (write) + if (exclusive) WARN_ON(atomic_read(&uobj->usecnt) > 0); else WARN_ON(atomic_read(&uobj->usecnt) == -1); @@ -465,29 +467,29 @@ 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) +static void lookup_put_idr_uobject(struct ib_uobject *uobj, bool exclusive) { } -static void lookup_put_fd_uobject(struct ib_uobject *uobj, bool write) +static void lookup_put_fd_uobject(struct ib_uobject *uobj, bool exclusive) { struct file *filp = uobj->object; - WARN_ON(write); + WARN_ON(exclusive); /* This indirectly calls uverbs_close_fd and free the object */ fput(filp); } -void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool write) +void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool exclusive) { - lockdep_check(uobj, write); - uobj->type->type_class->lookup_put(uobj, write); + lockdep_check(uobj, exclusive); + uobj->type->type_class->lookup_put(uobj, exclusive); /* * In order to unlock an object, either decrease its usecnt for - * read access or zero it in case of write access. See + * read access or zero it in case of exclusive access. See * uverbs_try_lock_object for locking schema information. */ - if (!write) + if (!exclusive) atomic_dec(&uobj->usecnt); else atomic_set(&uobj->usecnt, 0); @@ -512,7 +514,7 @@ const struct uverbs_obj_type_class uverbs_idr_class = { * 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 + * exclusive 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, diff --git a/include/rdma/uverbs_types.h b/include/rdma/uverbs_types.h index a37692167a45..351ea185df44 100644 --- a/include/rdma/uverbs_types.h +++ b/include/rdma/uverbs_types.h @@ -54,17 +54,18 @@ struct uverbs_obj_type_class { * destroyed. * [lookup]: Starts with lookup_get which fetches and locks the * object. After the handler finished using the object, it - * needs to call lookup_put to unlock it. The write flag - * indicates if the object is locked for exclusive access. - * [remove]: Starts with lookup_get with write flag set. This locks - * the object for exclusive access. If the handler code - * completed successfully, remove_commit is called and - * the ib_uobject is removed from the context's uobjects - * repository and put. The object itself is destroyed as - * well. Once remove succeeds new krefs to the object - * cannot be acquired by other threads or userspace and - * the hardware driver is removed from the object. - * Other krefs on the object may still exist. + * needs to call lookup_put to unlock it. The exclusive + * flag indicates if the object is locked for exclusive + * access. + * [remove]: Starts with lookup_get with exclusive flag set. This + * locks the object for exclusive access. If the handler + * code completed successfully, remove_commit is called + * and the ib_uobject is removed from the context's + * uobjects repository and put. The object itself is + * destroyed as well. Once remove succeeds new krefs to + * the object cannot be acquired by other threads or + * userspace and the hardware driver is removed from the + * object. Other krefs on the object may still exist. * If the handler code failed, lookup_put should be * called. This callback is used when the context * is destroyed as well (process termination, @@ -77,10 +78,10 @@ struct uverbs_obj_type_class { struct ib_uobject *(*lookup_get)(const struct uverbs_obj_type *type, struct ib_ucontext *ucontext, int id, - bool write); - void (*lookup_put)(struct ib_uobject *uobj, bool write); + bool exclusive); + void (*lookup_put)(struct ib_uobject *uobj, bool exclusive); /* - * Must be called with the write lock held. If successful uobj is + * Must be called with the exclusive lock held. If successful uobj is * invalid on return. On failure uobject is left completely * unchanged */ @@ -121,8 +122,8 @@ struct uverbs_obj_idr_type { struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_obj_type *type, struct ib_ucontext *ucontext, - int id, bool write); -void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool write); + int id, bool exclusive); +void rdma_lookup_put_uobject(struct ib_uobject *uobj, bool exclusive); struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_obj_type *type, struct ib_ucontext *ucontext); void rdma_alloc_abort_uobject(struct ib_uobject *uobj); |