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 static void netfs_free_request(struct work_struct *work); 14 15 /* 16 * Allocate an I/O request and initialise it. 17 */ 18 struct 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(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(10); 36 } 37 38 memset(rreq, 0, kmem_cache_size(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(&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(&rreq->io_streams[0].subrequests); 53 INIT_LIST_HEAD(&rreq->io_streams[1].subrequests); 54 init_waitqueue_head(&rreq->waitq); 55 refcount_set(&rreq->ref, 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(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool); 75 return ERR_PTR(ret); 76 } 77 } 78 79 atomic_inc(&ctx->io_count); 80 trace_netfs_rreq_ref(rreq->debug_id, refcount_read(&rreq->ref), netfs_rreq_trace_new); 81 netfs_proc_add_rreq(rreq); 82 netfs_stat(&netfs_n_rh_rreq); 83 return rreq; 84 } 85 86 void netfs_get_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what) 87 { 88 int r; 89 90 __refcount_inc(&rreq->ref, &r); 91 trace_netfs_rreq_ref(rreq->debug_id, r + 1, what); 92 } 93 94 void 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(&stream->subrequests)) { 103 subreq = list_first_entry(&stream->subrequests, 104 struct netfs_io_subrequest, rreq_link); 105 list_del(&subreq->rreq_link); 106 netfs_put_subrequest(subreq, netfs_sreq_trace_put_clear); 107 } 108 } 109 } 110 111 static 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(rreq, rreq->netfs_ops->request_pool ?: &netfs_request_pool); 116 netfs_stat_d(&netfs_n_rh_rreq); 117 } 118 119 static void netfs_deinit_request(struct netfs_io_request *rreq) 120 { 121 struct netfs_inode *ictx = netfs_inode(rreq->inode); 122 unsigned int i; 123 124 trace_netfs_rreq(rreq, 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(&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(rreq->direct_bv[i].bv_page); 142 } 143 } 144 kvfree(rreq->direct_bv); 145 } 146 rolling_buffer_clear(&rreq->buffer); 147 148 if (atomic_dec_and_test(&ictx->io_count)) 149 wake_up_var(&ictx->io_count); 150 } 151 152 static 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(&rreq->rcu, netfs_free_request_rcu); 159 } 160 161 void 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(&rreq->ref, &r); 170 trace_netfs_rreq_ref(debug_id, 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 */ 180 void netfs_put_failed_request(struct netfs_io_request *rreq) 181 { 182 int r = refcount_read(&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, r, netfs_rreq_trace_put_failed); 191 netfs_free_request(&rreq->cleanup_work); 192 } 193 194 /* 195 * Allocate and partially initialise an I/O request structure. 196 */ 197 struct 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(10); 209 } 210 211 memset(subreq, 0, kmem_cache_size(cache)); 212 INIT_WORK(&subreq->work, NULL); 213 INIT_LIST_HEAD(&subreq->rreq_link); 214 refcount_set(&subreq->ref, 2); 215 subreq->rreq = rreq; 216 subreq->debug_index = atomic_inc_return(&rreq->subreq_counter); 217 netfs_get_request(rreq, netfs_rreq_trace_get_subreq); 218 netfs_stat(&netfs_n_rh_sreq); 219 return subreq; 220 } 221 222 void netfs_get_subrequest(struct netfs_io_subrequest *subreq, 223 enum netfs_sreq_ref_trace what) 224 { 225 int r; 226 227 __refcount_inc(&subreq->ref, &r); 228 trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1, 229 what); 230 } 231 232 static void netfs_free_subrequest(struct netfs_io_subrequest *subreq) 233 { 234 struct netfs_io_request *rreq = subreq->rreq; 235 236 trace_netfs_sreq(subreq, netfs_sreq_trace_free); 237 if (rreq->netfs_ops->free_subrequest) 238 rreq->netfs_ops->free_subrequest(subreq); 239 mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool); 240 netfs_stat_d(&netfs_n_rh_sreq); 241 netfs_put_request(rreq, netfs_rreq_trace_put_subreq); 242 } 243 244 void 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(&subreq->ref, &r); 253 trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what); 254 if (dead) 255 netfs_free_subrequest(subreq); 256 } 257