projects/linux·blob master · refs

271 lines · 7.6 KiB

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 ([email protected])
6 */
7
8#include <linux/slab.h>
9#include <linux/mempool.h>
10#include "internal.h"
11
12static void netfs_free_request(struct work_struct *work);
13
14/*
15 * Allocate an I/O request and initialise it.
16 */
17struct netfs_io_request *netfs_alloc_request(struct address_space *mapping,
18 struct file *file,
19 uoff_t start, size_t len,
20 enum netfs_io_origin origin)
21{
22 static atomic_t debug_ids;
23 struct inode *inode = file ? file_inode(file) : mapping->host;
24 struct netfs_inode *ctx = netfs_inode(inode);
25 struct netfs_io_request *rreq;
26 mempool_t *mempool = ctx->ops->request_pool ?: &netfs_request_pool;
27 struct kmem_cache *cache = mempool->pool_data;
28 gfp_t gfp = GFP_KERNEL;
29 int ret;
30
31 /* Writeback is part of memory reclaim and must not fail due to ENOMEM. */
32 if (origin == NETFS_WRITEBACK || origin == NETFS_WRITEBACK_SINGLE) {
33 gfp = GFP_NOFS; /* Allows use of mempools. */
34
35 rreq = mempool_alloc(mempool, gfp);
36 } else {
37 rreq = mempool_alloc_noreserve(mempool, gfp);
38 if (!rreq)
39 return ERR_PTR(-ENOMEM);
40 }
41
42 memset(rreq, 0, kmem_cache_size(cache));
43 INIT_WORK(&rreq->cleanup_work, netfs_free_request);
44 rreq->gfp = gfp;
45 rreq->start = start;
46 rreq->collected_to = start;
47 rreq->cache_coll_to = start;
48 rreq->cleaned_to = start;
49 rreq->len = len;
50 rreq->progress_at = 0;
51 rreq->origin = origin;
52 rreq->netfs_ops = ctx->ops;
53 rreq->mapping = mapping;
54 rreq->inode = inode;
55 rreq->i_size = i_size_read(inode);
56 rreq->debug_id = atomic_inc_return(&debug_ids);
57 rreq->wsize = INT_MAX;
58 rreq->io_streams[0].sreq_max_len = ULONG_MAX;
59 rreq->io_streams[0].sreq_max_segs = 0;
60 spin_lock_init(&rreq->lock);
61 init_waitqueue_head(&rreq->waitq);
62 refcount_set(&rreq->ref, 2);
63
64 for (int s = 0; s < NR_IO_STREAMS; s++) {
65 struct netfs_io_stream *stream = &rreq->io_streams[s];
66
67 INIT_LIST_HEAD(&stream->subrequests);
68 stream->collected_to = rreq->start;
69 }
70
71 if (origin == NETFS_READAHEAD ||
72 origin == NETFS_READPAGE ||
73 origin == NETFS_READ_GAPS ||
74 origin == NETFS_READ_SINGLE ||
75 origin == NETFS_READ_FOR_WRITE ||
76 origin == NETFS_UNBUFFERED_READ ||
77 origin == NETFS_DIO_READ) {
78 INIT_WORK(&rreq->work, netfs_read_collection_worker);
79 rreq->io_streams[0].avail = true;
80 } else {
81 INIT_WORK(&rreq->work, netfs_write_collection_worker);
82 }
83
84 __set_bit(NETFS_RREQ_IN_PROGRESS, &rreq->flags);
85 if (rreq->netfs_ops->init_request) {
86 ret = rreq->netfs_ops->init_request(rreq, file);
87 if (ret < 0) {
88 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
89 return ERR_PTR(ret);
90 }
91 }
92
93 atomic_inc(&ctx->io_count);
94 trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), netfs_rreq_trace_new);
95 netfs_proc_add_rreq(rreq);
96 netfs_stat(&netfs_n_rh_rreq);
97 return rreq;
98}
99
100void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
101{
102 int r;
103
104 __refcount_inc(&rreq->ref, &r);
105 trace_netfs_rreq_ref(rreq->debug_id, r + 1, what);
106}
107
108void netfs_clear_subrequests(struct netfs_io_request *rreq)
109{
110 struct netfs_io_subrequest *subreq;
111 struct netfs_io_stream *stream;
112 int s;
113
114 for (s = 0; s < ARRAY_SIZE(rreq->io_streams); s++) {
115 stream = &rreq->io_streams[s];
116 while (!list_empty(&stream->subrequests)) {
117 subreq = list_first_entry(&stream->subrequests,
118 struct netfs_io_subrequest, rreq_link);
119 list_del(&subreq->rreq_link);
120 netfs_put_subrequest(subreq, netfs_sreq_trace_put_clear);
121 }
122 }
123}
124
125static void netfs_free_request_rcu(struct rcu_head *rcu)
126{
127 struct netfs_io_request *rreq = container_of(rcu, struct netfs_io_request, rcu);
128
129 mempool_free(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool);
130 netfs_stat_d(&netfs_n_rh_rreq);
131}
132
133static void netfs_deinit_request(struct netfs_io_request *rreq)
134{
135 struct netfs_inode *ictx = netfs_inode(rreq->inode);
136 unsigned int i;
137
138 trace_netfs_rreq(rreq, netfs_rreq_trace_free);
139
140 /* Cancel/flush the result collection worker. That does not carry a
141 * ref of its own, so we must wait for it somewhere.
142 */
143 cancel_work_sync(&rreq->work);
144
145 netfs_proc_del_rreq(rreq);
146 netfs_clear_subrequests(rreq);
147 if (rreq->netfs_ops->free_request)
148 rreq->netfs_ops->free_request(rreq);
149 if (rreq->cache_resources.ops)
150 rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
151 if (rreq->direct_bv) {
152 for (i = 0; i < rreq->direct_bv_count; i++) {
153 if (rreq->direct_bv[i].bv_page) {
154 if (rreq->direct_bv_unpin)
155 unpin_user_page(rreq->direct_bv[i].bv_page);
156 }
157 }
158 kvfree(rreq->direct_bv);
159 }
160 rolling_buffer_clear(&rreq->buffer);
161
162 if (atomic_dec_and_test(&ictx->io_count))
163 wake_up_var(&ictx->io_count);
164}
165
166static void netfs_free_request(struct work_struct *work)
167{
168 struct netfs_io_request *rreq =
169 container_of(work, struct netfs_io_request, cleanup_work);
170
171 netfs_deinit_request(rreq);
172 call_rcu(&rreq->rcu, netfs_free_request_rcu);
173}
174
175void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
176{
177 unsigned int debug_id;
178 bool dead;
179 int r;
180
181 if (rreq) {
182 debug_id = rreq->debug_id;
183 dead = __refcount_dec_and_test(&rreq->ref, &r);
184 trace_netfs_rreq_ref(debug_id, r - 1, what);
185 if (dead)
186 WARN_ON(!queue_work(system_dfl_wq, &rreq->cleanup_work));
187 }
188}
189
190/*
191 * Free a request (synchronously) that was just allocated but has
192 * failed before it could be submitted.
193 */
194void netfs_put_failed_request(struct netfs_io_request *rreq)
195{
196 int r = refcount_read(&rreq->ref);
197
198 /* new requests have two references (see
199 * netfs_alloc_request(), and this function is only allowed on
200 * new request objects
201 */
202 WARN_ON_ONCE(r != 2);
203
204 trace_netfs_rreq_ref(rreq->debug_id, r, netfs_rreq_trace_put_failed);
205 netfs_free_request(&rreq->cleanup_work);
206}
207
208/*
209 * Allocate and partially initialise an I/O request structure.
210 */
211struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq,
212 enum netfs_io_source source)
213{
214 struct netfs_io_subrequest *subreq;
215 mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
216 struct kmem_cache *cache = mempool->pool_data;
217
218 if (rreq->gfp == GFP_KERNEL)
219 subreq = mempool_alloc_noreserve(mempool, rreq->gfp);
220 else
221 subreq = mempool_alloc(mempool, rreq->gfp);
222 if (!subreq)
223 return NULL;
224
225 memset(subreq, 0, kmem_cache_size(cache));
226 INIT_WORK(&subreq->work, NULL);
227 INIT_LIST_HEAD(&subreq->rreq_link);
228 refcount_set(&subreq->ref, 2);
229 subreq->source = source;
230 subreq->rreq = rreq;
231 subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
232 netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
233 netfs_stat(&netfs_n_rh_sreq);
234 return subreq;
235}
236
237void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
238 enum netfs_sreq_ref_trace what)
239{
240 int r;
241
242 __refcount_inc(&subreq->ref, &r);
243 trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
244 what);
245}
246
247static void netfs_free_subrequest(struct netfs_io_subrequest *subreq)
248{
249 struct netfs_io_request *rreq = subreq->rreq;
250
251 trace_netfs_sreq(subreq, netfs_sreq_trace_free);
252 if (rreq->netfs_ops->free_subrequest)
253 rreq->netfs_ops->free_subrequest(subreq);
254 mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
255 netfs_stat_d(&netfs_n_rh_sreq);
256 netfs_put_request(rreq, netfs_rreq_trace_put_subreq);
257}
258
259void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
260 enum netfs_sreq_ref_trace what)
261{
262 unsigned int debug_index = subreq->debug_index;
263 unsigned int debug_id = subreq->rreq->debug_id;
264 bool dead;
265 int r;
266
267 dead = __refcount_dec_and_test(&subreq->ref, &r);
268 trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
269 if (dead)
270 netfs_free_subrequest(subreq);
271}