1// SPDX-License-Identifier: GPL-2.0-only
  2/* Object lifetime handling and tracing.
  3 *
  4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
  5 * Written by David Howells (dhowells@redhat.com)
  6 */
  7
  8#include <linux/slab.h>
  9#include <linux/mempool.h>
 10#include <linux/delay.h>
 11#include "internal.h"
 12
 13/*
 14 * Allocate an I/O request and initialise it.
 15 */
 16struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
 17					     struct file *file,
 18					     loff_t start, size_t len,
 19					     enum netfs_io_origin origin)
 20{
 21	static atomic_t debug_ids;
 22	struct inode *inode = file ? file_inode(file) : mapping->host;
 23	struct netfs_inode *ctx = netfs_inode(inode);
 24	struct netfs_io_request *rreq;
 25	mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
 26	struct kmem_cache *cache = mempool->pool_data;
 27	int ret;
 28
 29	for (;;) {
 30		rreq = mempool_alloc(mempool, GFP_KERNEL);
 31		if (rreq)
 32			break;
 33		msleep(10);
 34	}
 35
 36	memset(rreq, 0, kmem_cache_size(cache));
 37	rreq->start	= start;
 38	rreq->len	= len;
 39	rreq->origin	= origin;
 40	rreq->netfs_ops	= ctx->ops;
 41	rreq->mapping	= mapping;
 42	rreq->inode	= inode;
 43	rreq->i_size	= i_size_read(inode);
 44	rreq->debug_id	= atomic_inc_return(&debug_ids);
 45	rreq->wsize	= INT_MAX;
 46	rreq->io_streams[0].sreq_max_len = ULONG_MAX;
 47	rreq->io_streams[0].sreq_max_segs = 0;
 48	spin_lock_init(&rreq->lock);
 49	INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
 50	INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
 51	INIT_LIST_HEAD(&rreq->subrequests);
 52	refcount_set(&rreq->ref, 1);
 53
 54	if (origin == NETFS_READAHEAD ||
 55	    origin == NETFS_READPAGE ||
 56	    origin == NETFS_READ_GAPS ||
 57	    origin == NETFS_READ_FOR_WRITE ||
 58	    origin == NETFS_DIO_READ)
 59		INIT_WORK(&rreq->work, netfs_read_termination_worker);
 60	else
 61		INIT_WORK(&rreq->work, netfs_write_collection_worker);
 62
 63	__set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
 64	if (file && file->f_flags & O_NONBLOCK)
 65		__set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
 66	if (rreq->netfs_ops->init_request) {
 67		ret = rreq->netfs_ops->init_request(rreq, file);
 68		if (ret < 0) {
 69			mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
 70			return ERR_PTR(ret);
 71		}
 72	}
 73
 74	atomic_inc(&ctx->io_count);
 75	trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
 76	netfs_proc_add_rreq(rreq);
 77	netfs_stat(&netfs_n_rh_rreq);
 78	return rreq;
 79}
 80
 81void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
 82{
 83	int r;
 84
 85	__refcount_inc(&rreq->ref, &r);
 86	trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
 87}
 88
 89void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
 90{
 91	struct netfs_io_subrequest *subreq;
 92	struct netfs_io_stream *stream;
 93	int s;
 94
 95	while (!list_empty(&rreq->subrequests)) {
 96		subreq = list_first_entry(&rreq->subrequests,
 97					  struct netfs_io_subrequest, rreq_link);
 98		list_del(&subreq->rreq_link);
 99		netfs_put_subrequest(subreq, was_async,
100				     netfs_sreq_trace_put_clear);
101	}
102
103	for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
104		stream = &rreq->io_streams[s];
105		while (!list_empty(&stream->subrequests)) {
106			subreq = list_first_entry(&stream->subrequests,
107						  struct netfs_io_subrequest, rreq_link);
108			list_del(&subreq->rreq_link);
109			netfs_put_subrequest(subreq, was_async,
110					     netfs_sreq_trace_put_clear);
111		}
112	}
113}
114
115static void netfs_free_request_rcu(struct rcu_head *rcu)
116{
117	struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
118
119	mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
120	netfs_stat_d(&netfs_n_rh_rreq);
121}
122
123static void netfs_free_request(struct work_struct *work)
124{
125	struct netfs_io_request *rreq =
126		container_of(work, struct netfs_io_request, work);
127	struct netfs_inode *ictx = netfs_inode(rreq->inode);
128	unsigned int i;
129
130	trace_netfs_rreq(rreq, netfs_rreq_trace_free);
131	netfs_proc_del_rreq(rreq);
132	netfs_clear_subrequests(rreq, false);
133	if (rreq->netfs_ops->free_request)
134		rreq->netfs_ops->free_request(rreq);
135	if (rreq->cache_resources.ops)
136		rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
137	if (rreq->direct_bv) {
138		for (i = 0; i < rreq->direct_bv_count; i++) {
139			if (rreq->direct_bv[i].bv_page) {
140				if (rreq->direct_bv_unpin)
141					unpin_user_page(rreq->direct_bv[i].bv_page);
142			}
143		}
144		kvfree(rreq->direct_bv);
145	}
146	netfs_clear_buffer(rreq);
147
148	if (atomic_dec_and_test(&ictx->io_count))
149		wake_up_var(&ictx->io_count);
150	call_rcu(&rreq->rcu, netfs_free_request_rcu);
151}
152
153void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
154		       enum netfs_rreq_ref_trace what)
155{
156	unsigned int debug_id;
157	bool dead;
158	int r;
159
160	if (rreq) {
161		debug_id = rreq->debug_id;
162		dead = __refcount_dec_and_test(&rreq->ref, &r);
163		trace_netfs_rreq_ref(debug_id, r - 1, what);
164		if (dead) {
165			if (was_async) {
166				rreq->work.func = netfs_free_request;
167				if (!queue_work(system_unbound_wq, &rreq->work))
168					WARN_ON(1);
169			} else {
170				netfs_free_request(&rreq->work);
171			}
172		}
173	}
174}
175
176/*
177 * Allocate and partially initialise an I/O request structure.
178 */
179struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
180{
181	struct netfs_io_subrequest *subreq;
182	mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
183	struct kmem_cache *cache = mempool->pool_data;
184
185	for (;;) {
186		subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
187				       GFP_KERNEL);
188		if (subreq)
189			break;
190		msleep(10);
191	}
192
193	memset(subreq, 0, kmem_cache_size(cache));
194	INIT_WORK(&subreq->work, NULL);
195	INIT_LIST_HEAD(&subreq->rreq_link);
196	refcount_set(&subreq->ref, 2);
197	subreq->rreq = rreq;
198	subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
199	netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
200	netfs_stat(&netfs_n_rh_sreq);
201	return subreq;
202}
203
204void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
205			  enum netfs_sreq_ref_trace what)
206{
207	int r;
208
209	__refcount_inc(&subreq->ref, &r);
210	trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
211			     what);
212}
213
214static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
215				  bool was_async)
216{
217	struct netfs_io_request *rreq = subreq->rreq;
218
219	trace_netfs_sreq(subreq, netfs_sreq_trace_free);
220	if (rreq->netfs_ops->free_subrequest)
221		rreq->netfs_ops->free_subrequest(subreq);
222	mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
223	netfs_stat_d(&netfs_n_rh_sreq);
224	netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
225}
226
227void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async,
228			  enum netfs_sreq_ref_trace what)
229{
230	unsigned int debug_index = subreq->debug_index;
231	unsigned int debug_id = subreq->rreq->debug_id;
232	bool dead;
233	int r;
234
235	dead = __refcount_dec_and_test(&subreq->ref, &r);
236	trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
237	if (dead)
238		netfs_free_subrequest(subreq, was_async);
239}