提交 30004b86 编写于 作者: M Matan Barak 提交者: Doug Ledford

IB/core: Rename write flag to exclusive in rdma_core

We rename the "write" flags to "exclusive", as it's used for both
WRITE and DESTROY actions.

Fixes: 38321256 ('IB/core: Add support for idr types')
Signed-off-by: NMatan Barak <matanb@mellanox.com>
Reviewed-by: NSean Hefty <sean.hefty@intel.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>
上级 b58fc804
......@@ -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 @@ static struct ib_uobject *lookup_get_idr_uobject(const struct uverbs_obj_type *t
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,
......
......@@ -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);
......
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