/* SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB */
/*
 * Copyright (c) 2017, Mellanox Technologies inc.  All rights reserved.
 */

#ifndef _UVERBS_TYPES_
#define _UVERBS_TYPES_

#include <linux/kernel.h>
#include <rdma/ib_verbs.h>

struct uverbs_obj_type;
struct uverbs_api_object;

enum rdma_lookup_mode {
        UVERBS_LOOKUP_READ,
        UVERBS_LOOKUP_WRITE,
        /*
         * Destroy is like LOOKUP_WRITE, except that the uobject is not
         * locked.  uobj_destroy is used to convert a LOOKUP_DESTROY lock into
         * a LOOKUP_WRITE lock.
         */
        UVERBS_LOOKUP_DESTROY,
};

/*
 * The following sequences are valid:
 * Success flow:
 *   alloc_begin
 *   alloc_commit
 *    [..]
 * Access flow:
 *   lookup_get(exclusive=false) & uverbs_try_lock_object
 *   lookup_put(exclusive=false) via rdma_lookup_put_uobject
 * Destruction flow:
 *   lookup_get(exclusive=true) & uverbs_try_lock_object
 *   remove_commit
 *   remove_handle (optional)
 *   lookup_put(exclusive=true) via rdma_lookup_put_uobject
 *
 * Allocate Error flow #1
 *   alloc_begin
 *   alloc_abort
 * Allocate Error flow #2
 *   alloc_begin
 *   remove_commit
 *   alloc_abort
 * Allocate Error flow #3
 *   alloc_begin
 *   alloc_commit (fails)
 *   remove_commit
 *   alloc_abort
 *
 * In all cases the caller must hold the ufile kref until alloc_commit or
 * alloc_abort returns.
 */
struct uverbs_obj_type_class {
        struct ib_uobject *(*alloc_begin)(const struct uverbs_api_object *obj,
                                          struct uverbs_attr_bundle *attrs);
        /* This consumes the kref on uobj */
        void (*alloc_commit)(struct ib_uobject *uobj);
        /* This does not consume the kref on uobj */
        void (*alloc_abort)(struct ib_uobject *uobj);

        struct ib_uobject *(*lookup_get)(const struct uverbs_api_object *obj,
                                         struct ib_uverbs_file *ufile, s64 id,
                                         enum rdma_lookup_mode mode);
        void (*lookup_put)(struct ib_uobject *uobj, enum rdma_lookup_mode mode);
        /* This does not consume the kref on uobj */
        int __must_check (*destroy_hw)(struct ib_uobject *uobj,
                                       enum rdma_remove_reason why,
                                       struct uverbs_attr_bundle *attrs);
        void (*remove_handle)(struct ib_uobject *uobj);
        void (*swap_uobjects)(struct ib_uobject *obj_old,
                              struct ib_uobject *obj_new);
};

struct uverbs_obj_type {
        const struct uverbs_obj_type_class * const type_class;
        size_t       obj_size;
};

/*
 * Objects type classes which support a detach state (object is still alive but
 * it's not attached to any context need to make sure:
 * (a) no call through to a driver after a detach is called
 * (b) detach isn't called concurrently with context_cleanup
 */

struct uverbs_obj_idr_type {
        /*
         * In idr based objects, uverbs_obj_type_class points to a generic
         * idr operations. In order to specialize the underlying types (e.g. CQ,
         * QPs, etc.), we add destroy_object specific callbacks.
         */
        struct uverbs_obj_type  type;

        /* Free driver resources from the uobject, make the driver uncallable,
         * and move the uobject to the detached state. If the object was
         * destroyed by the user's request, a failure should leave the uobject
         * completely unchanged.
         */
        int __must_check (*destroy_object)(struct ib_uobject *uobj,
                                           enum rdma_remove_reason why,
                                           struct uverbs_attr_bundle *attrs);
};

struct ib_uobject *rdma_lookup_get_uobject(const struct uverbs_api_object *obj,
                                           struct ib_uverbs_file *ufile, s64 id,
                                           enum rdma_lookup_mode mode,
                                           struct uverbs_attr_bundle *attrs);
void rdma_lookup_put_uobject(struct ib_uobject *uobj,
                             enum rdma_lookup_mode mode);
struct ib_uobject *rdma_alloc_begin_uobject(const struct uverbs_api_object *obj,
                                            struct uverbs_attr_bundle *attrs);
void rdma_alloc_abort_uobject(struct ib_uobject *uobj,
                              struct uverbs_attr_bundle *attrs,
                              bool hw_obj_valid);
void rdma_alloc_commit_uobject(struct ib_uobject *uobj,
                               struct uverbs_attr_bundle *attrs);
void rdma_assign_uobject(struct ib_uobject *to_uobj,
                         struct ib_uobject *new_uobj,
                         struct uverbs_attr_bundle *attrs);

/*
 * uverbs_uobject_get is called in order to increase the reference count on
 * an uobject. This is useful when a handler wants to keep the uobject's memory
 * alive, regardless if this uobject is still alive in the context's objects
 * repository. Objects are put via uverbs_uobject_put.
 */
static inline void uverbs_uobject_get(struct ib_uobject *uobject)
{
        kref_get(&uobject->ref);
}
void uverbs_uobject_put(struct ib_uobject *uobject);

int uverbs_try_lock_object(struct ib_uobject *uobj, enum rdma_lookup_mode mode);

struct uverbs_obj_fd_type {
        /*
         * In fd based objects, uverbs_obj_type_ops points to generic
         * fd operations. In order to specialize the underlying types (e.g.
         * completion_channel), we use fops, name and flags for fd creation.
         * destroy_object is called when the uobject is to be destroyed,
         * because the driver is removed or the FD is closed.
         */
        struct uverbs_obj_type  type;
        void (*destroy_object)(struct ib_uobject *uobj,
                               enum rdma_remove_reason why);
        const struct file_operations    *fops;
        const char                      *name;
        int                             flags;
};

struct ib_uverbs_file {
        struct kref                             ref;
        struct ib_uverbs_device                *device;
        struct mutex                            ucontext_lock;
        /*
         * ucontext must be accessed via ib_uverbs_get_ucontext() or with
         * ucontext_lock held
         */
        struct ib_ucontext                     *ucontext;
        struct ib_uverbs_async_event_file      *default_async_file;
        struct list_head                        list;

        /*
         * To access the uobjects list hw_destroy_rwsem must be held for write
         * OR hw_destroy_rwsem held for read AND uobjects_lock held.
         * hw_destroy_rwsem should be called across any destruction of the HW
         * object of an associated uobject.
         */
        struct rw_semaphore     hw_destroy_rwsem;
        spinlock_t              uobjects_lock;
        struct list_head        uobjects;

        struct mutex umap_lock;
        struct list_head umaps;
        struct page *disassociate_page;

        struct xarray           idr;

        struct mutex disassociation_lock;
};

extern const struct uverbs_obj_type_class uverbs_idr_class;
extern const struct uverbs_obj_type_class uverbs_fd_class;
int uverbs_uobject_fd_release(struct inode *inode, struct file *filp);
int uverbs_uobject_release(struct ib_uobject *uobj);

#define UVERBS_BUILD_BUG_ON(cond) (sizeof(char[1 - 2 * !!(cond)]) -     \
                                   sizeof(char))
#define UVERBS_TYPE_ALLOC_FD(_obj_size, _destroy_object, _fops, _name, _flags) \
        ((&((const struct uverbs_obj_fd_type)                           \
         {.type = {                                                     \
                .type_class = &uverbs_fd_class,                         \
                .obj_size = (_obj_size) +                               \
                        UVERBS_BUILD_BUG_ON((_obj_size) <               \
                                            sizeof(struct ib_uobject)), \
         },                                                             \
         .destroy_object = _destroy_object,                             \
         .fops = _fops,                                                 \
         .name = _name,                                                 \
         .flags = _flags}))->type)
#define UVERBS_TYPE_ALLOC_IDR_SZ(_size, _destroy_object)        \
        ((&((const struct uverbs_obj_idr_type)                          \
         {.type = {                                                     \
                .type_class = &uverbs_idr_class,                        \
                .obj_size = (_size) +                                   \
                        UVERBS_BUILD_BUG_ON((_size) <                   \
                                            sizeof(struct ib_uobject))  \
         },                                                             \
         .destroy_object = _destroy_object,}))->type)
#define UVERBS_TYPE_ALLOC_IDR(_destroy_object)                  \
         UVERBS_TYPE_ALLOC_IDR_SZ(sizeof(struct ib_uobject),    \
                                  _destroy_object)

#endif