Linux kernel mirror (for testing)
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linux
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->upper_len = len;
40 rreq->origin = origin;
41 rreq->netfs_ops = ctx->ops;
42 rreq->mapping = mapping;
43 rreq->inode = inode;
44 rreq->i_size = i_size_read(inode);
45 rreq->debug_id = atomic_inc_return(&debug_ids);
46 rreq->wsize = INT_MAX;
47 spin_lock_init(&rreq->lock);
48 INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
49 INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
50 INIT_LIST_HEAD(&rreq->subrequests);
51 INIT_WORK(&rreq->work, NULL);
52 refcount_set(&rreq->ref, 1);
53
54 __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
55 if (file && file->f_flags & O_NONBLOCK)
56 __set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
57 if (rreq->netfs_ops->init_request) {
58 ret = rreq->netfs_ops->init_request(rreq, file);
59 if (ret < 0) {
60 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
61 return ERR_PTR(ret);
62 }
63 }
64
65 atomic_inc(&ctx->io_count);
66 trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
67 netfs_proc_add_rreq(rreq);
68 netfs_stat(&netfs_n_rh_rreq);
69 return rreq;
70}
71
72void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
73{
74 int r;
75
76 __refcount_inc(&rreq->ref, &r);
77 trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
78}
79
80void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
81{
82 struct netfs_io_subrequest *subreq;
83 struct netfs_io_stream *stream;
84 int s;
85
86 while (!list_empty(&rreq->subrequests)) {
87 subreq = list_first_entry(&rreq->subrequests,
88 struct netfs_io_subrequest, rreq_link);
89 list_del(&subreq->rreq_link);
90 netfs_put_subrequest(subreq, was_async,
91 netfs_sreq_trace_put_clear);
92 }
93
94 for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
95 stream = &rreq->io_streams[s];
96 while (!list_empty(&stream->subrequests)) {
97 subreq = list_first_entry(&stream->subrequests,
98 struct netfs_io_subrequest, rreq_link);
99 list_del(&subreq->rreq_link);
100 netfs_put_subrequest(subreq, was_async,
101 netfs_sreq_trace_put_clear);
102 }
103 }
104}
105
106static void netfs_free_request_rcu(struct rcu_head *rcu)
107{
108 struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
109
110 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
111 netfs_stat_d(&netfs_n_rh_rreq);
112}
113
114static void netfs_free_request(struct work_struct *work)
115{
116 struct netfs_io_request *rreq =
117 container_of(work, struct netfs_io_request, work);
118 struct netfs_inode *ictx = netfs_inode(rreq->inode);
119 unsigned int i;
120
121 trace_netfs_rreq(rreq, netfs_rreq_trace_free);
122 netfs_proc_del_rreq(rreq);
123 netfs_clear_subrequests(rreq, false);
124 if (rreq->netfs_ops->free_request)
125 rreq->netfs_ops->free_request(rreq);
126 if (rreq->cache_resources.ops)
127 rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
128 if (rreq->direct_bv) {
129 for (i = 0; i < rreq->direct_bv_count; i++) {
130 if (rreq->direct_bv[i].bv_page) {
131 if (rreq->direct_bv_unpin)
132 unpin_user_page(rreq->direct_bv[i].bv_page);
133 }
134 }
135 kvfree(rreq->direct_bv);
136 }
137
138 if (atomic_dec_and_test(&ictx->io_count))
139 wake_up_var(&ictx->io_count);
140 call_rcu(&rreq->rcu, netfs_free_request_rcu);
141}
142
143void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
144 enum netfs_rreq_ref_trace what)
145{
146 unsigned int debug_id;
147 bool dead;
148 int r;
149
150 if (rreq) {
151 debug_id = rreq->debug_id;
152 dead = __refcount_dec_and_test(&rreq->ref, &r);
153 trace_netfs_rreq_ref(debug_id, r - 1, what);
154 if (dead) {
155 if (was_async) {
156 rreq->work.func = netfs_free_request;
157 if (!queue_work(system_unbound_wq, &rreq->work))
158 BUG();
159 } else {
160 netfs_free_request(&rreq->work);
161 }
162 }
163 }
164}
165
166/*
167 * Allocate and partially initialise an I/O request structure.
168 */
169struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
170{
171 struct netfs_io_subrequest *subreq;
172 mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
173 struct kmem_cache *cache = mempool->pool_data;
174
175 for (;;) {
176 subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
177 GFP_KERNEL);
178 if (subreq)
179 break;
180 msleep(10);
181 }
182
183 memset(subreq, 0, kmem_cache_size(cache));
184 INIT_WORK(&subreq->work, NULL);
185 INIT_LIST_HEAD(&subreq->rreq_link);
186 refcount_set(&subreq->ref, 2);
187 subreq->rreq = rreq;
188 subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
189 netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
190 netfs_stat(&netfs_n_rh_sreq);
191 return subreq;
192}
193
194void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
195 enum netfs_sreq_ref_trace what)
196{
197 int r;
198
199 __refcount_inc(&subreq->ref, &r);
200 trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
201 what);
202}
203
204static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
205 bool was_async)
206{
207 struct netfs_io_request *rreq = subreq->rreq;
208
209 trace_netfs_sreq(subreq, netfs_sreq_trace_free);
210 if (rreq->netfs_ops->free_subrequest)
211 rreq->netfs_ops->free_subrequest(subreq);
212 mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
213 netfs_stat_d(&netfs_n_rh_sreq);
214 netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
215}
216
217void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async,
218 enum netfs_sreq_ref_trace what)
219{
220 unsigned int debug_index = subreq->debug_index;
221 unsigned int debug_id = subreq->rreq->debug_id;
222 bool dead;
223 int r;
224
225 dead = __refcount_dec_and_test(&subreq->ref, &r);
226 trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
227 if (dead)
228 netfs_free_subrequest(subreq, was_async);
229}