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 */
netfs_alloc_request(struct address_space * mapping,struct file * file,loff_t start,size_t len,enum netfs_io_origin origin)16 struct 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_waitqueue_head(&rreq->waitq);
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_SINGLE ||
58 origin == NETFS_READ_FOR_WRITE ||
59 origin == NETFS_DIO_READ) {
60 INIT_WORK(&rreq->work, netfs_read_collection_worker);
61 rreq->io_streams[0].avail = true;
62 } else {
63 INIT_WORK(&rreq->work, netfs_write_collection_worker);
64 }
65
66 __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
67 if (file && file->f_flags & O_NONBLOCK)
68 __set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
69 if (rreq->netfs_ops->init_request) {
70 ret = rreq->netfs_ops->init_request(rreq, file);
71 if (ret < 0) {
72 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
73 return ERR_PTR(ret);
74 }
75 }
76
77 atomic_inc(&ctx->io_count);
78 trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
79 netfs_proc_add_rreq(rreq);
80 netfs_stat(&netfs_n_rh_rreq);
81 return rreq;
82 }
83
netfs_get_request(struct netfs_io_request * rreq,enum netfs_rreq_ref_trace what)84 void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
85 {
86 int r;
87
88 __refcount_inc(&rreq->ref, &r);
89 trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
90 }
91
netfs_clear_subrequests(struct netfs_io_request * rreq,bool was_async)92 void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
93 {
94 struct netfs_io_subrequest *subreq;
95 struct netfs_io_stream *stream;
96 int s;
97
98 for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
99 stream = &rreq->io_streams[s];
100 while (!list_empty(&stream->subrequests)) {
101 subreq = list_first_entry(&stream->subrequests,
102 struct netfs_io_subrequest, rreq_link);
103 list_del(&subreq->rreq_link);
104 netfs_put_subrequest(subreq, was_async,
105 netfs_sreq_trace_put_clear);
106 }
107 }
108 }
109
netfs_free_request_rcu(struct rcu_head * rcu)110 static void netfs_free_request_rcu(struct rcu_head *rcu)
111 {
112 struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
113
114 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
115 netfs_stat_d(&netfs_n_rh_rreq);
116 }
117
netfs_free_request(struct work_struct * work)118 static void netfs_free_request(struct work_struct *work)
119 {
120 struct netfs_io_request *rreq =
121 container_of(work, struct netfs_io_request, work);
122 struct netfs_inode *ictx = netfs_inode(rreq->inode);
123 unsigned int i;
124
125 trace_netfs_rreq(rreq, netfs_rreq_trace_free);
126 netfs_proc_del_rreq(rreq);
127 netfs_clear_subrequests(rreq, false);
128 if (rreq->netfs_ops->free_request)
129 rreq->netfs_ops->free_request(rreq);
130 if (rreq->cache_resources.ops)
131 rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
132 if (rreq->direct_bv) {
133 for (i = 0; i < rreq->direct_bv_count; i++) {
134 if (rreq->direct_bv[i].bv_page) {
135 if (rreq->direct_bv_unpin)
136 unpin_user_page(rreq->direct_bv[i].bv_page);
137 }
138 }
139 kvfree(rreq->direct_bv);
140 }
141 rolling_buffer_clear(&rreq->buffer);
142
143 if (atomic_dec_and_test(&ictx->io_count))
144 wake_up_var(&ictx->io_count);
145 call_rcu(&rreq->rcu, netfs_free_request_rcu);
146 }
147
netfs_put_request(struct netfs_io_request * rreq,bool was_async,enum netfs_rreq_ref_trace what)148 void netfs_put_request(struct netfs_io_request *rreq, bool was_async,
149 enum netfs_rreq_ref_trace what)
150 {
151 unsigned int debug_id;
152 bool dead;
153 int r;
154
155 if (rreq) {
156 debug_id = rreq->debug_id;
157 dead = __refcount_dec_and_test(&rreq->ref, &r);
158 trace_netfs_rreq_ref(debug_id, r - 1, what);
159 if (dead) {
160 if (was_async) {
161 rreq->work.func = netfs_free_request;
162 if (!queue_work(system_unbound_wq, &rreq->work))
163 WARN_ON(1);
164 } else {
165 netfs_free_request(&rreq->work);
166 }
167 }
168 }
169 }
170
171 /*
172 * Allocate and partially initialise an I/O request structure.
173 */
netfs_alloc_subrequest(struct netfs_io_request * rreq)174 struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
175 {
176 struct netfs_io_subrequest *subreq;
177 mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
178 struct kmem_cache *cache = mempool->pool_data;
179
180 for (;;) {
181 subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
182 GFP_KERNEL);
183 if (subreq)
184 break;
185 msleep(10);
186 }
187
188 memset(subreq, 0, kmem_cache_size(cache));
189 INIT_WORK(&subreq->work, NULL);
190 INIT_LIST_HEAD(&subreq->rreq_link);
191 refcount_set(&subreq->ref, 2);
192 subreq->rreq = rreq;
193 subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
194 netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
195 netfs_stat(&netfs_n_rh_sreq);
196 return subreq;
197 }
198
netfs_get_subrequest(struct netfs_io_subrequest * subreq,enum netfs_sreq_ref_trace what)199 void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
200 enum netfs_sreq_ref_trace what)
201 {
202 int r;
203
204 __refcount_inc(&subreq->ref, &r);
205 trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
206 what);
207 }
208
netfs_free_subrequest(struct netfs_io_subrequest * subreq,bool was_async)209 static void netfs_free_subrequest(struct netfs_io_subrequest *subreq,
210 bool was_async)
211 {
212 struct netfs_io_request *rreq = subreq->rreq;
213
214 trace_netfs_sreq(subreq, netfs_sreq_trace_free);
215 if (rreq->netfs_ops->free_subrequest)
216 rreq->netfs_ops->free_subrequest(subreq);
217 mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
218 netfs_stat_d(&netfs_n_rh_sreq);
219 netfs_put_request(rreq, was_async, netfs_rreq_trace_put_subreq);
220 }
221
netfs_put_subrequest(struct netfs_io_subrequest * subreq,bool was_async,enum netfs_sreq_ref_trace what)222 void netfs_put_subrequest(struct netfs_io_subrequest *subreq, bool was_async,
223 enum netfs_sreq_ref_trace what)
224 {
225 unsigned int debug_index = subreq->debug_index;
226 unsigned int debug_id = subreq->rreq->debug_id;
227 bool dead;
228 int r;
229
230 dead = __refcount_dec_and_test(&subreq->ref, &r);
231 trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
232 if (dead)
233 netfs_free_subrequest(subreq, was_async);
234 }
235