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 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_free_request(struct work_struct *work)
 120 {
 121         struct netfs_io_request *rreq =
 122                 container_of(work, struct netfs_io_request, cleanup_work);
 123         struct netfs_inode *ictx = netfs_inode(rreq->inode);
 124         unsigned int i;
 125
 126         trace_netfs_rreq(rreq, netfs_rreq_trace_free);
 127
 128         /* Cancel/flush the result collection worker.  That does not carry a
 129          * ref of its own, so we must wait for it somewhere.
 130          */
 131         cancel_work_sync(&rreq->work);
 132
 133         netfs_proc_del_rreq(rreq);
 134         netfs_clear_subrequests(rreq);
 135         if (rreq->netfs_ops->free_request)
 136                 rreq->netfs_ops->free_request(rreq);
 137         if (rreq->cache_resources.ops)
 138                 rreq->cache_resources.ops->end_operation(&rreq->cache_resources);
 139         if (rreq->direct_bv) {
 140                 for (i = 0; i < rreq->direct_bv_count; i++) {
 141                         if (rreq->direct_bv[i].bv_page) {
 142                                 if (rreq->direct_bv_unpin)
 143                                         unpin_user_page(rreq->direct_bv[i].bv_page);
 144                         }
 145                 }
 146                 kvfree(rreq->direct_bv);
 147         }
 148         rolling_buffer_clear(&rreq->buffer);
 149
 150         if (atomic_dec_and_test(&ictx->io_count))
 151                 wake_up_var(&ictx->io_count);
 152         call_rcu(&rreq->rcu, netfs_free_request_rcu);
 153 }
 154
 155 void netfs_put_request(struct netfs_io_request *rreq, enum netfs_rreq_ref_trace what)
 156 {
 157         unsigned int debug_id;
 158         bool dead;
 159         int r;
 160
 161         if (rreq) {
 162                 debug_id = rreq->debug_id;
 163                 dead = __refcount_dec_and_test(&rreq->ref, &r);
 164                 trace_netfs_rreq_ref(debug_id, r - 1, what);
 165                 if (dead)
 166                         WARN_ON(!queue_work(system_unbound_wq, &rreq->cleanup_work));
 167         }
 168 }
 169
 170 /*
 171  * Allocate and partially initialise an I/O request structure.
 172  */
 173 struct netfs_io_subrequest *netfs_alloc_subrequest(struct netfs_io_request *rreq)
 174 {
 175         struct netfs_io_subrequest *subreq;
 176         mempool_t *mempool = rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool;
 177         struct kmem_cache *cache = mempool->pool_data;
 178
 179         for (;;) {
 180                 subreq = mempool_alloc(rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool,
 181                                        GFP_KERNEL);
 182                 if (subreq)
 183                         break;
 184                 msleep(10);
 185         }
 186
 187         memset(subreq, 0, kmem_cache_size(cache));
 188         INIT_WORK(&subreq->work, NULL);
 189         INIT_LIST_HEAD(&subreq->rreq_link);
 190         refcount_set(&subreq->ref, 2);
 191         subreq->rreq = rreq;
 192         subreq->debug_index = atomic_inc_return(&rreq->subreq_counter);
 193         netfs_get_request(rreq, netfs_rreq_trace_get_subreq);
 194         netfs_stat(&netfs_n_rh_sreq);
 195         return subreq;
 196 }
 197
 198 void netfs_get_subrequest(struct netfs_io_subrequest *subreq,
 199                           enum netfs_sreq_ref_trace what)
 200 {
 201         int r;
 202
 203         __refcount_inc(&subreq->ref, &r);
 204         trace_netfs_sreq_ref(subreq->rreq->debug_id, subreq->debug_index, r + 1,
 205                              what);
 206 }
 207
 208 static void netfs_free_subrequest(struct netfs_io_subrequest *subreq)
 209 {
 210         struct netfs_io_request *rreq = subreq->rreq;
 211
 212         trace_netfs_sreq(subreq, netfs_sreq_trace_free);
 213         if (rreq->netfs_ops->free_subrequest)
 214                 rreq->netfs_ops->free_subrequest(subreq);
 215         mempool_free(subreq, rreq->netfs_ops->subrequest_pool ?: &netfs_subrequest_pool);
 216         netfs_stat_d(&netfs_n_rh_sreq);
 217         netfs_put_request(rreq, netfs_rreq_trace_put_subreq);
 218 }
 219
 220 void netfs_put_subrequest(struct netfs_io_subrequest *subreq,
 221                           enum netfs_sreq_ref_trace what)
 222 {
 223         unsigned int debug_index = subreq->debug_index;
 224         unsigned int debug_id = subreq->rreq->debug_id;
 225         bool dead;
 226         int r;
 227
 228         dead = __refcount_dec_and_test(&subreq->ref, &r);
 229         trace_netfs_sreq_ref(debug_id, debug_index, r - 1, what);
 230         if (dead)
 231                 netfs_free_subrequest(subreq);
 232 }