e951747a08
The locking here has always been a bit crazy and spread out, upon some careful analysis we can simplify things. Create a single function uverbs_destroy_ufile_hw() that internally handles all locking. This pulls together pieces of this process that were sprinkled all over the places into one place, and covers them with one lock. This eliminates several duplicate/confusing locks and makes the control flow in ib_uverbs_close() and ib_uverbs_free_hw_resources() extremely simple. Unfortunately we have to keep an extra mutex, ucontext_lock. This lock is logically part of the rwsem and provides the 'down write, fail if write locked, wait if read locked' semantic we require. Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
112 lines
4.7 KiB
C
112 lines
4.7 KiB
C
/*
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* Copyright (c) 2005 Topspin Communications. All rights reserved.
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* Copyright (c) 2005, 2006 Cisco Systems. All rights reserved.
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* Copyright (c) 2005-2017 Mellanox Technologies. All rights reserved.
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* Copyright (c) 2005 Voltaire, Inc. All rights reserved.
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* Copyright (c) 2005 PathScale, Inc. All rights reserved.
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*
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* This software is available to you under a choice of one of two
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* licenses. You may choose to be licensed under the terms of the GNU
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* General Public License (GPL) Version 2, available from the file
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* COPYING in the main directory of this source tree, or the
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* OpenIB.org BSD license below:
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* - Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* - Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#ifndef RDMA_CORE_H
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#define RDMA_CORE_H
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#include <linux/idr.h>
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#include <rdma/uverbs_types.h>
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#include <rdma/uverbs_ioctl.h>
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#include <rdma/ib_verbs.h>
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#include <linux/mutex.h>
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int uverbs_ns_idx(u16 *id, unsigned int ns_count);
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const struct uverbs_object_spec *uverbs_get_object(struct ib_uverbs_file *ufile,
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uint16_t object);
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const struct uverbs_method_spec *uverbs_get_method(const struct uverbs_object_spec *object,
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uint16_t method);
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void uverbs_destroy_ufile_hw(struct ib_uverbs_file *ufile,
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enum rdma_remove_reason reason);
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/*
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* uverbs_uobject_get is called in order to increase the reference count on
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* an uobject. This is useful when a handler wants to keep the uobject's memory
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* alive, regardless if this uobject is still alive in the context's objects
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* repository. Objects are put via uverbs_uobject_put.
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*/
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void uverbs_uobject_get(struct ib_uobject *uobject);
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/*
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* In order to indicate we no longer needs this uobject, uverbs_uobject_put
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* is called. When the reference count is decreased, the uobject is freed.
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* For example, this is used when attaching a completion channel to a CQ.
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*/
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void uverbs_uobject_put(struct ib_uobject *uobject);
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/* Indicate this fd is no longer used by this consumer, but its memory isn't
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* necessarily released yet. When the last reference is put, we release the
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* memory. After this call is executed, calling uverbs_uobject_get isn't
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* allowed.
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* This must be called from the release file_operations of the file!
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*/
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void uverbs_close_fd(struct file *f);
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/*
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* Get an ib_uobject that corresponds to the given id from ufile, assuming
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* the object is from the given type. Lock it to the required access when
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* applicable.
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* This function could create (access == NEW), destroy (access == DESTROY)
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* or unlock (access == READ || access == WRITE) objects if required.
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* The action will be finalized only when uverbs_finalize_object or
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* uverbs_finalize_objects are called.
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*/
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struct ib_uobject *
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uverbs_get_uobject_from_file(const struct uverbs_obj_type *type_attrs,
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struct ib_uverbs_file *ufile,
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enum uverbs_obj_access access, s64 id);
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/*
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* Note that certain finalize stages could return a status:
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* (a) alloc_commit could return a failure if the object is committed at the
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* same time when the context is destroyed.
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* (b) remove_commit could fail if the object wasn't destroyed successfully.
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* Since multiple objects could be finalized in one transaction, it is very NOT
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* recommended to have several finalize actions which have side effects.
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* For example, it's NOT recommended to have a certain action which has both
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* a commit action and a destroy action or two destroy objects in the same
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* action. The rule of thumb is to have one destroy or commit action with
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* multiple lookups.
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* The first non zero return value of finalize_object is returned from this
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* function. For example, this could happen when we couldn't destroy an
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* object.
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*/
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int uverbs_finalize_object(struct ib_uobject *uobj,
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enum uverbs_obj_access access,
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bool commit);
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#endif /* RDMA_CORE_H */
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