main.c

  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_SINGLE]		= "R1",
 41	[NETFS_READ_FOR_WRITE]		= "RW",
 42	[NETFS_UNBUFFERED_READ]		= "UR",
 43	[NETFS_DIO_READ]		= "DR",
 44	[NETFS_WRITEBACK]		= "WB",
 45	[NETFS_WRITEBACK_SINGLE]	= "W1",
 46	[NETFS_WRITETHROUGH]		= "WT",
 47	[NETFS_UNBUFFERED_WRITE]	= "UW",
 48	[NETFS_DIO_WRITE]		= "DW",
 49	[NETFS_PGPRIV2_COPY_TO_CACHE]	= "2C",
 50};
 51
 52/*
 53 * Generate a list of I/O requests in /proc/fs/netfs/requests
 54 */
 55static int netfs_requests_seq_show(struct seq_file *m, void *v)
 56{
 57	struct netfs_io_request *rreq;
 58
 59	if (v == &netfs_io_requests) {
 60		seq_puts(m,
 61			 "REQUEST  OR REF FLAG ERR  OPS COVERAGE\n"
 62			 "======== == === ==== ==== === =========\n"
 63			 );
 64		return 0;
 65	}
 66
 67	rreq = list_entry(v, struct netfs_io_request, proc_link);
 68	seq_printf(m,
 69		   "%08x %s %3d %4lx %4ld %3d @%04llx %llx/%llx",
 70		   rreq->debug_id,
 71		   netfs_origins[rreq->origin],
 72		   refcount_read(&rreq->ref),
 73		   rreq->flags,
 74		   rreq->error,
 75		   0,
 76		   rreq->start, rreq->submitted, rreq->len);
 77	seq_putc(m, '\n');
 78	return 0;
 79}
 80
 81static void *netfs_requests_seq_start(struct seq_file *m, loff_t *_pos)
 82	__acquires(rcu)
 83{
 84	rcu_read_lock();
 85	return seq_list_start_head(&netfs_io_requests, *_pos);
 86}
 87
 88static void *netfs_requests_seq_next(struct seq_file *m, void *v, loff_t *_pos)
 89{
 90	return seq_list_next(v, &netfs_io_requests, _pos);
 91}
 92
 93static void netfs_requests_seq_stop(struct seq_file *m, void *v)
 94	__releases(rcu)
 95{
 96	rcu_read_unlock();
 97}
 98
 99static const struct seq_operations netfs_requests_seq_ops = {
100	.start  = netfs_requests_seq_start,
101	.next   = netfs_requests_seq_next,
102	.stop   = netfs_requests_seq_stop,
103	.show   = netfs_requests_seq_show,
104};
105#endif /* CONFIG_PROC_FS */
106
107static int __init netfs_init(void)
108{
109	int ret = -ENOMEM;
110
111	netfs_request_slab = kmem_cache_create("netfs_request",
112					       sizeof(struct netfs_io_request), 0,
113					       SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
114					       NULL);
115	if (!netfs_request_slab)
116		goto error_req;
117
118	if (mempool_init_slab_pool(&netfs_request_pool, 100, netfs_request_slab) < 0)
119		goto error_reqpool;
120
121	netfs_subrequest_slab = kmem_cache_create("netfs_subrequest",
122						  sizeof(struct netfs_io_subrequest) + 16, 0,
123						  SLAB_HWCACHE_ALIGN | SLAB_ACCOUNT,
124						  NULL);
125	if (!netfs_subrequest_slab)
126		goto error_subreq;
127
128	if (mempool_init_slab_pool(&netfs_subrequest_pool, 100, netfs_subrequest_slab) < 0)
129		goto error_subreqpool;
130
131#ifdef CONFIG_PROC_FS
132	if (!proc_mkdir("fs/netfs", NULL))
133		goto error_proc;
134	if (!proc_create_seq("fs/netfs/requests", S_IFREG | 0444, NULL,
135			     &netfs_requests_seq_ops))
136		goto error_procfile;
137#endif
138#ifdef CONFIG_FSCACHE_STATS
139	if (!proc_create_single("fs/netfs/stats", S_IFREG | 0444, NULL,
140				netfs_stats_show))
141		goto error_procfile;
142#endif
143
144	ret = fscache_init();
145	if (ret < 0)
146		goto error_fscache;
147	return 0;
148
149error_fscache:
150#ifdef CONFIG_PROC_FS
151error_procfile:
152	remove_proc_subtree("fs/netfs", NULL);
153error_proc:
154#endif
155	mempool_exit(&netfs_subrequest_pool);
156error_subreqpool:
157	kmem_cache_destroy(netfs_subrequest_slab);
158error_subreq:
159	mempool_exit(&netfs_request_pool);
160error_reqpool:
161	kmem_cache_destroy(netfs_request_slab);
162error_req:
163	return ret;
164}
165fs_initcall(netfs_init);
166
167static void __exit netfs_exit(void)
168{
169	fscache_exit();
170	remove_proc_subtree("fs/netfs", NULL);
171	mempool_exit(&netfs_subrequest_pool);
172	kmem_cache_destroy(netfs_subrequest_slab);
173	mempool_exit(&netfs_request_pool);
174	kmem_cache_destroy(netfs_request_slab);
175}
176module_exit(netfs_exit);