1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* Miscellaneous bits for the netfs support library.
  3 *
  4 * Copyright (C) 2022 Red Hat, Inc. All Rights Reserved.
  5 * Written by David Howells (dhowells@redhat.com)
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/export.h>
 10#include <linux/mempool.h>
 11#include <linux/proc_fs.h>
 12#include <linux/seq_file.h>
 13#include "internal.h"
 14#define CREATE_TRACE_POINTS
 15#include <trace/events/netfs.h>
 16
 17MODULE_DESCRIPTION("Network fs support");
 18MODULE_AUTHOR("Red Hat, Inc.");
 19MODULE_LICENSE("GPL");
 20
 21EXPORT_TRACEPOINT_SYMBOL(netfs_sreq);
 22
 23unsigned netfs_debug;
 24module_param_named(debug, netfs_debug, uint, S_IWUSR | S_IRUGO);
 25MODULE_PARM_DESC(netfs_debug, "Netfs support debugging mask");
 26
 27static struct kmem_cache *netfs_request_slab;
 28static struct kmem_cache *netfs_subrequest_slab;
 29mempool_t netfs_request_pool;
 30mempool_t netfs_subrequest_pool;
 31
 32#ifdef CONFIG_PROC_FS
 33LIST_HEAD(netfs_io_requests);
 34DEFINE_SPINLOCK(netfs_proc_lock);
 35
 36static const char *netfs_origins[nr__netfs_io_origin] = {
 37	[NETFS_READAHEAD]		= "RA",
 38	[NETFS_READPAGE]		= "RP",
 39	[NETFS_READ_GAPS]		= "RG",
 40	[NETFS_READ_FOR_WRITE]		= "RW",
 41	[NETFS_DIO_READ]		= "DR",
 42	[NETFS_WRITEBACK]		= "WB",
 43	[NETFS_WRITETHROUGH]		= "WT",
 44	[NETFS_UNBUFFERED_WRITE]	= "UW",
 45	[NETFS_DIO_WRITE]		= "DW",
 46	[NETFS_PGPRIV2_COPY_TO_CACHE]	= "2C",
 47};
 48
 49/*
 50 * Generate a list of I/O requests in /proc/fs/netfs/requests
 51 */
 52static int netfs_requests_seq_show(struct seq_file *m, void *v)
 53{
 54	struct netfs_io_request *rreq;
 55
 56	if (v == &netfs_io_requests) {
 57		seq_puts(m,
 58			 "REQUEST  OR REF FL ERR  OPS COVERAGE\n"
 59			 "======== == === == ==== === =========\n"
 60			 );
 61		return 0;
 62	}
 63
 64	rreq = list_entry(v, struct netfs_io_request, proc_link);
 65	seq_printf(m,
 66		   "%08x %s %3d %2lx %4ld %3d @%04llx %llx/%llx",
 67		   rreq->debug_id,
 68		   netfs_origins[rreq->origin],
 69		   refcount_read(&rreq->ref),
 70		   rreq->flags,
 71		   rreq->error,
 72		   atomic_read(&rreq->nr_outstanding),
 73		   rreq->start, rreq->submitted, rreq->len);
 74	seq_putc(m, '\n');
 75	return 0;
 76}
 77
 78static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
 79	__acquires(rcu)
 80{
 81	rcu_read_lock();
 82	return seq_list_start_head(&netfs_io_requests, *_pos);
 83}
 84
 85static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
 86{
 87	return seq_list_next(v, &netfs_io_requests, _pos);
 88}
 89
 90static void netfs_requests_seq_stop(struct seq_file *m, void *v)
 91	__releases(rcu)
 92{
 93	rcu_read_unlock();
 94}
 95
 96static const struct seq_operations netfs_requests_seq_ops = {
 97	.start  = netfs_requests_seq_start,
 98	.next   = netfs_requests_seq_next,
 99	.stop   = netfs_requests_seq_stop,
100	.show   = netfs_requests_seq_show,
101};
102#endif /* CONFIG_PROC_FS */
103
104static int __init netfs_init(void)
105{
106	int ret = -ENOMEM;
107
108	netfs_request_slab = kmem_cache_create("netfs_request",
109					       sizeof(struct netfs_io_request), 0,
110					       SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
111					       NULL);
112	if (!netfs_request_slab)
113		goto error_req;
114
115	if (mempool_init_slab_pool(&netfs_request_pool, 100, netfs_request_slab) < 0)
116		goto error_reqpool;
117
118	netfs_subrequest_slab = kmem_cache_create("netfs_subrequest",
119						  sizeof(struct netfs_io_subrequest), 0,
120						  SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
121						  NULL);
122	if (!netfs_subrequest_slab)
123		goto error_subreq;
124
125	if (mempool_init_slab_pool(&netfs_subrequest_pool, 100, netfs_subrequest_slab) < 0)
126		goto error_subreqpool;
127
128	if (!proc_mkdir("fs/netfs", NULL))
129		goto error_proc;
130	if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
131			     &netfs_requests_seq_ops))
132		goto error_procfile;
133#ifdef CONFIG_FSCACHE_STATS
134	if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
135				netfs_stats_show))
136		goto error_procfile;
137#endif
138
139	ret = fscache_init();
140	if (ret < 0)
141		goto error_fscache;
142	return 0;
143
144error_fscache:
145error_procfile:
146	remove_proc_subtree("fs/netfs", NULL);
147error_proc:
148	mempool_exit(&netfs_subrequest_pool);
149error_subreqpool:
150	kmem_cache_destroy(netfs_subrequest_slab);
151error_subreq:
152	mempool_exit(&netfs_request_pool);
153error_reqpool:
154	kmem_cache_destroy(netfs_request_slab);
155error_req:
156	return ret;
157}
158fs_initcall(netfs_init);
159
160static void __exit netfs_exit(void)
161{
162	fscache_exit();
163	remove_proc_subtree("fs/netfs", NULL);
164	mempool_exit(&netfs_subrequest_pool);
165	kmem_cache_destroy(netfs_subrequest_slab);
166	mempool_exit(&netfs_request_pool);
167	kmem_cache_destroy(netfs_request_slab);
168}
169module_exit(netfs_exit);