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 bool is_unbuffered = (origin == NETFS_UNBUFFERED_WRITE ||
28 origin == NETFS_DIO_READ ||
29 origin == NETFS_DIO_WRITE);
30 bool cached = !is_unbuffered && netfs_is_cache_enabled(ctx);
31 int ret;
32
33 for (;;) {
34 rreq = mempool_alloc(mempool, GFP_KERNEL);
35 if (rreq)
36 break;
37 msleep(10);
38 }
39
40 memset(rreq, 0, kmem_cache_size(cache));
41 rreq->start = start;
42 rreq->len = len;
43 rreq->upper_len = len;
44 rreq->origin = origin;
45 rreq->netfs_ops = ctx->ops;
46 rreq->mapping = mapping;
47 rreq->inode = inode;
48 rreq->i_size = i_size_read(inode);
49 rreq->debug_id = atomic_inc_return(&debug_ids);
50 rreq->wsize = INT_MAX;
51 spin_lock_init(&rreq->lock);
52 INIT_LIST_HEAD(&rreq->io_streams[0].subrequests);
53 INIT_LIST_HEAD(&rreq->io_streams[1].subrequests);
54 INIT_LIST_HEAD(&rreq->subrequests);
55 INIT_WORK(&rreq->work, NULL);
56 refcount_set(&rreq->ref, 1);
57
58 __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
59 if (cached) {
60 __set_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags);
61 if (test_bit(NETFS_ICTX_USE_PGPRIV2, &ctx->flags))
62 /* Filesystem uses deprecated PG_private_2 marking. */
63 __set_bit(NETFS_RREQ_USE_PGPRIV2, &rreq->flags);
64 }
65 if (file && file->f_flags & O_NONBLOCK)
66 __set_bit(NETFS_RREQ_NONBLOCK, &rreq->flags);
67 if (rreq->netfs_ops->init_request) {
68 ret = rreq->netfs_ops->init_request(rreq, file);
69 if (ret < 0) {
70 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
71 return ERR_PTR(ret);
72 }
73 }
74
75 atomic_inc(&ctx->io_count);
76 trace_netfs_rreq_ref(rreq->debug_id, 1, netfs_rreq_trace_new);
77 netfs_proc_add_rreq(rreq);
78 netfs_stat(&netfs_n_rh_rreq);
79 return rreq;
80 }
81
netfs_get_request(struct netfs_io_request * rreq,enum netfs_rreq_ref_trace what)82 void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
83 {
84 int r;
85
86 __refcount_inc(&rreq->ref, &r);
87 trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
88 }
89
netfs_clear_subrequests(struct netfs_io_request * rreq,bool was_async)90 void netfs_clear_subrequests(struct netfs_io_request *rreq, bool was_async)
91 {
92 struct netfs_io_subrequest *subreq;
93 struct netfs_io_stream *stream;
94 int s;
95
96 while (!list_empty(&rreq->subrequests)) {
97 subreq = list_first_entry(&rreq->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 for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
105 stream = &rreq->io_streams[s];
106 while (!list_empty(&stream->subrequests)) {
107 subreq = list_first_entry(&stream->subrequests,
108 struct netfs_io_subrequest, rreq_link);
109 list_del(&subreq->rreq_link);
110 netfs_put_subrequest(subreq, was_async,
111 netfs_sreq_trace_put_clear);
112 }
113 }
114 }
115
netfs_free_request_rcu(struct rcu_head * rcu)116 static void netfs_free_request_rcu(struct rcu_head *rcu)
117 {
118 struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
119
120 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
121 netfs_stat_d(&netfs_n_rh_rreq);
122 }
123
netfs_free_request(struct work_struct * work)124 static void netfs_free_request(struct work_struct *work)
125 {
126 struct netfs_io_request *rreq =
127 container_of(work, struct netfs_io_request, work);
128 struct netfs_inode *ictx = netfs_inode(rreq->inode);
129 unsigned int i;
130
131 trace_netfs_rreq(rreq, netfs_rreq_trace_free);
132 netfs_proc_del_rreq(rreq);
133 netfs_clear_subrequests(rreq, false);
134 if (rreq->netfs_ops->free_request)
135 rreq->netfs_ops->free_request(rreq);
136 if (rreq->cache_resources.ops)
137 rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
138 if (rreq->direct_bv) {
139 for (i = 0; i < rreq->direct_bv_count; i++) {
140 if (rreq->direct_bv[i].bv_page) {
141 if (rreq->direct_bv_unpin)
142 unpin_user_page(rreq->direct_bv[i].bv_page);
143 }
144 }
145 kvfree(rreq->direct_bv);
146 }
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
netfs_put_request(struct netfs_io_request * rreq,bool was_async,enum netfs_rreq_ref_trace what)153 void 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 BUG();
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 */
netfs_alloc_subrequest(struct netfs_io_request * rreq)179 struct 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
netfs_get_subrequest(struct netfs_io_subrequest * subreq,enum netfs_sreq_ref_trace what)204 void 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
netfs_free_subrequest(struct netfs_io_subrequest * subreq,bool was_async)214 static 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
netfs_put_subrequest(struct netfs_io_subrequest * subreq,bool was_async,enum netfs_sreq_ref_trace what)227 void 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 }
240