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
13static void netfs_free_request(struct work_struct *work);
14
15/*
16 * Allocate an I/O request and initialise it.
17 */
18struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
19 struct file *file,
20 loff_t start, size_t len,
21 enum netfs_io_origin origin)
22{
23 static atomic_t debug_ids;
24 struct inode *inode = file ? file_inode(f: file) : mapping->host;
25 struct netfs_inode *ctx = netfs_inode(inode);
26 struct netfs_io_request *rreq;
27 mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
28 struct kmem_cache *cache = mempool->pool_data;
29 int ret;
30
31 for (;;) {
32 rreq = mempool_alloc(mempool, GFP_KERNEL);
33 if (rreq)
34 break;
35 msleep(msecs: 10);
36 }
37
38 memset(s: rreq, c: 0, n: kmem_cache_size(s: cache));
39 INIT_WORK(&rreq->cleanup_work, netfs_free_request);
40 rreq->start = start;
41 rreq->len = len;
42 rreq->origin = origin;
43 rreq->netfs_ops = ctx->ops;
44 rreq->mapping = mapping;
45 rreq->inode = inode;
46 rreq->i_size = i_size_read(inode);
47 rreq->debug_id = atomic_inc_return(v: &debug_ids);
48 rreq->wsize = INT_MAX;
49 rreq->io_streams[0].sreq_max_len = ULONG_MAX;
50 rreq->io_streams[0].sreq_max_segs = 0;
51 spin_lock_init(&rreq->lock);
52 INIT_LIST_HEAD(list: &rreq->io_streams[0].subrequests);
53 INIT_LIST_HEAD(list: &rreq->io_streams[1].subrequests);
54 init_waitqueue_head(&rreq->waitq);
55 refcount_set(r: &rreq->ref, n: 2);
56
57 if (origin == NETFS_READAHEAD ||
58 origin == NETFS_READPAGE ||
59 origin == NETFS_READ_GAPS ||
60 origin == NETFS_READ_SINGLE ||
61 origin == NETFS_READ_FOR_WRITE ||
62 origin == NETFS_UNBUFFERED_READ ||
63 origin == NETFS_DIO_READ) {
64 INIT_WORK(&rreq->work, netfs_read_collection_worker);
65 rreq->io_streams[0].avail = true;
66 } else {
67 INIT_WORK(&rreq->work, netfs_write_collection_worker);
68 }
69
70 __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
71 if (rreq->netfs_ops->init_request) {
72 ret = rreq->netfs_ops->init_request(rreq, file);
73 if (ret < 0) {
74 mempool_free(element: rreq, pool: rreq->netfs_ops->request_pool ?: &netfs_request_pool);
75 return ERR_PTR(error: ret);
76 }
77 }
78
79 atomic_inc(v: &ctx->io_count);
80 trace_netfs_rreq_ref(rreq_debug_id: rreq->debug_id, ref: refcount_read(r: &rreq->ref), what: netfs_rreq_trace_new);
81 netfs_proc_add_rreq(rreq);
82 netfs_stat(&netfs_n_rh_rreq);
83 return rreq;
84}
85
86void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
87{
88 int r;
89
90 __refcount_inc(r: &rreq->ref, oldp: &r);
91 trace_netfs_rreq_ref(rreq_debug_id: rreq->debug_id, ref: r + 1, what);
92}
93
94void netfs_clear_subrequests(struct netfs_io_request *rreq)
95{
96 struct netfs_io_subrequest *subreq;
97 struct netfs_io_stream *stream;
98 int s;
99
100 for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
101 stream = &rreq->io_streams[s];
102 while (!list_empty(head: &stream->subrequests)) {
103 subreq = list_first_entry(&stream->subrequests,
104 struct netfs_io_subrequest, rreq_link);
105 list_del(entry: &subreq->rreq_link);
106 netfs_put_subrequest(subreq, what: netfs_sreq_trace_put_clear);
107 }
108 }
109}
110
111static void netfs_free_request_rcu(struct rcu_head *rcu)
112{
113 struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
114
115 mempool_free(element: rreq, pool: rreq->netfs_ops->request_pool ?: &netfs_request_pool);
116 netfs_stat_d(&netfs_n_rh_rreq);
117}
118
119static void netfs_deinit_request(struct netfs_io_request *rreq)
120{
121 struct netfs_inode *ictx = netfs_inode(inode: rreq->inode);
122 unsigned int i;
123
124 trace_netfs_rreq(rreq, what: netfs_rreq_trace_free);
125
126 /* Cancel/flush the result collection worker. That does not carry a
127 * ref of its own, so we must wait for it somewhere.
128 */
129 cancel_work_sync(work: &rreq->work);
130
131 netfs_proc_del_rreq(rreq);
132 netfs_clear_subrequests(rreq);
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(page: rreq->direct_bv[i].bv_page);
142 }
143 }
144 kvfree(addr: rreq->direct_bv);
145 }
146 rolling_buffer_clear(roll: &rreq->buffer);
147
148 if (atomic_dec_and_test(v: &ictx->io_count))
149 wake_up_var(var: &ictx->io_count);
150}
151
152static void netfs_free_request(struct work_struct *work)
153{
154 struct netfs_io_request *rreq =
155 container_of(work, struct netfs_io_request, cleanup_work);
156
157 netfs_deinit_request(rreq);
158 call_rcu(head: &rreq->rcu, func: netfs_free_request_rcu);
159}
160
161void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
162{
163 unsigned int debug_id;
164 bool dead;
165 int r;
166
167 if (rreq) {
168 debug_id = rreq->debug_id;
169 dead = __refcount_dec_and_test(r: &rreq->ref, oldp: &r);
170 trace_netfs_rreq_ref(rreq_debug_id: debug_id, ref: r - 1, what);
171 if (dead)
172 WARN_ON(!queue_work(system_dfl_wq, &rreq->cleanup_work));
173 }
174}
175
176/*
177 * Free a request (synchronously) that was just allocated but has
178 * failed before it could be submitted.
179 */
180void netfs_put_failed_request(struct netfs_io_request *rreq)
181{
182 int r = refcount_read(r: &rreq->ref);
183
184 /* new requests have two references (see
185 * netfs_alloc_request(), and this function is only allowed on
186 * new request objects
187 */
188 WARN_ON_ONCE(r != 2);
189
190 trace_netfs_rreq_ref(rreq_debug_id: rreq->debug_id, ref: r, what: netfs_rreq_trace_put_failed);
191 netfs_free_request(work: &rreq->cleanup_work);
192}
193
194/*
195 * Allocate and partially initialise an I/O request structure.
196 */
197struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
198{
199 struct netfs_io_subrequest *subreq;
200 mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
201 struct kmem_cache *cache = mempool->pool_data;
202
203 for (;;) {
204 subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
205 GFP_KERNEL);
206 if (subreq)
207 break;
208 msleep(msecs: 10);
209 }
210
211 memset(s: subreq, c: 0, n: kmem_cache_size(s: cache));
212 INIT_WORK(&subreq->work, NULL);
213 INIT_LIST_HEAD(list: &subreq->rreq_link);
214 refcount_set(r: &subreq->ref, n: 2);
215 subreq->rreq = rreq;
216 subreq->debug_index = atomic_inc_return(v: &rreq->subreq_counter);
217 netfs_get_request(rreq, what: netfs_rreq_trace_get_subreq);
218 netfs_stat(&netfs_n_rh_sreq);
219 return subreq;
220}
221
222void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
223 enum netfs_sreq_ref_trace what)
224{
225 int r;
226
227 __refcount_inc(r: &subreq->ref, oldp: &r);
228 trace_netfs_sreq_ref(rreq_debug_id: subreq->rreq->debug_id, subreq_debug_index: subreq->debug_index, ref: r + 1,
229 what);
230}
231
232static void netfs_free_subrequest(struct netfs_io_subrequest *subreq)
233{
234 struct netfs_io_request *rreq = subreq->rreq;
235
236 trace_netfs_sreq(sreq: subreq, what: netfs_sreq_trace_free);
237 if (rreq->netfs_ops->free_subrequest)
238 rreq->netfs_ops->free_subrequest(subreq);
239 mempool_free(element: subreq, pool: rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
240 netfs_stat_d(&netfs_n_rh_sreq);
241 netfs_put_request(rreq, what: netfs_rreq_trace_put_subreq);
242}
243
244void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
245 enum netfs_sreq_ref_trace what)
246{
247 unsigned int debug_index = subreq->debug_index;
248 unsigned int debug_id = subreq->rreq->debug_id;
249 bool dead;
250 int r;
251
252 dead = __refcount_dec_and_test(r: &subreq->ref, oldp: &r);
253 trace_netfs_sreq_ref(rreq_debug_id: debug_id, subreq_debug_index: debug_index, ref: r - 1, what);
254 if (dead)
255 netfs_free_subrequest(subreq);
256}
257