fs/netfs/objects.c

   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  */
  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
  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
  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
 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
 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
 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  */
 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
 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
 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
 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 }