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-rw-r--r--kernel/trace/blktrace.c1549
1 files changed, 1549 insertions, 0 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
new file mode 100644
index 00000000000..947c5b3f90c
--- /dev/null
+++ b/kernel/trace/blktrace.c
@@ -0,0 +1,1549 @@
1/*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18#include <linux/kernel.h>
19#include <linux/blkdev.h>
20#include <linux/blktrace_api.h>
21#include <linux/percpu.h>
22#include <linux/init.h>
23#include <linux/mutex.h>
24#include <linux/debugfs.h>
25#include <linux/time.h>
26#include <trace/block.h>
27#include <linux/uaccess.h>
28#include "trace_output.h"
29
30static unsigned int blktrace_seq __read_mostly = 1;
31
32static struct trace_array *blk_tr;
33static bool blk_tracer_enabled __read_mostly;
34
35/* Select an alternative, minimalistic output than the original one */
36#define TRACE_BLK_OPT_CLASSIC 0x1
37
38static struct tracer_opt blk_tracer_opts[] = {
39 /* Default disable the minimalistic output */
40 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
41 { }
42};
43
44static struct tracer_flags blk_tracer_flags = {
45 .val = 0,
46 .opts = blk_tracer_opts,
47};
48
49/* Global reference count of probes */
50static atomic_t blk_probes_ref = ATOMIC_INIT(0);
51
52static void blk_register_tracepoints(void);
53static void blk_unregister_tracepoints(void);
54
55/*
56 * Send out a notify message.
57 */
58static void trace_note(struct blk_trace *bt, pid_t pid, int action,
59 const void *data, size_t len)
60{
61 struct blk_io_trace *t;
62 struct ring_buffer_event *event = NULL;
63 int pc = 0;
64 int cpu = smp_processor_id();
65 bool blk_tracer = blk_tracer_enabled;
66
67 if (blk_tracer) {
68 pc = preempt_count();
69 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
70 sizeof(*t) + len,
71 0, pc);
72 if (!event)
73 return;
74 t = ring_buffer_event_data(event);
75 goto record_it;
76 }
77
78 if (!bt->rchan)
79 return;
80
81 t = relay_reserve(bt->rchan, sizeof(*t) + len);
82 if (t) {
83 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
84 t->time = ktime_to_ns(ktime_get());
85record_it:
86 t->device = bt->dev;
87 t->action = action;
88 t->pid = pid;
89 t->cpu = cpu;
90 t->pdu_len = len;
91 memcpy((void *) t + sizeof(*t), data, len);
92
93 if (blk_tracer)
94 trace_buffer_unlock_commit(blk_tr, event, 0, pc);
95 }
96}
97
98/*
99 * Send out a notify for this process, if we haven't done so since a trace
100 * started
101 */
102static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
103{
104 tsk->btrace_seq = blktrace_seq;
105 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
106}
107
108static void trace_note_time(struct blk_trace *bt)
109{
110 struct timespec now;
111 unsigned long flags;
112 u32 words[2];
113
114 getnstimeofday(&now);
115 words[0] = now.tv_sec;
116 words[1] = now.tv_nsec;
117
118 local_irq_save(flags);
119 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
120 local_irq_restore(flags);
121}
122
123void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
124{
125 int n;
126 va_list args;
127 unsigned long flags;
128 char *buf;
129
130 if (unlikely(bt->trace_state != Blktrace_running &&
131 !blk_tracer_enabled))
132 return;
133
134 local_irq_save(flags);
135 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
136 va_start(args, fmt);
137 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
138 va_end(args);
139
140 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
141 local_irq_restore(flags);
142}
143EXPORT_SYMBOL_GPL(__trace_note_message);
144
145static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
146 pid_t pid)
147{
148 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
149 return 1;
150 if (sector < bt->start_lba || sector > bt->end_lba)
151 return 1;
152 if (bt->pid && pid != bt->pid)
153 return 1;
154
155 return 0;
156}
157
158/*
159 * Data direction bit lookup
160 */
161static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
162 BLK_TC_ACT(BLK_TC_WRITE) };
163
164/* The ilog2() calls fall out because they're constant */
165#define MASK_TC_BIT(rw, __name) ((rw & (1 << BIO_RW_ ## __name)) << \
166 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - BIO_RW_ ## __name))
167
168/*
169 * The worker for the various blk_add_trace*() types. Fills out a
170 * blk_io_trace structure and places it in a per-cpu subbuffer.
171 */
172static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
173 int rw, u32 what, int error, int pdu_len, void *pdu_data)
174{
175 struct task_struct *tsk = current;
176 struct ring_buffer_event *event = NULL;
177 struct blk_io_trace *t;
178 unsigned long flags = 0;
179 unsigned long *sequence;
180 pid_t pid;
181 int cpu, pc = 0;
182 bool blk_tracer = blk_tracer_enabled;
183
184 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
185 return;
186
187 what |= ddir_act[rw & WRITE];
188 what |= MASK_TC_BIT(rw, BARRIER);
189 what |= MASK_TC_BIT(rw, SYNCIO);
190 what |= MASK_TC_BIT(rw, AHEAD);
191 what |= MASK_TC_BIT(rw, META);
192 what |= MASK_TC_BIT(rw, DISCARD);
193
194 pid = tsk->pid;
195 if (unlikely(act_log_check(bt, what, sector, pid)))
196 return;
197 cpu = raw_smp_processor_id();
198
199 if (blk_tracer) {
200 tracing_record_cmdline(current);
201
202 pc = preempt_count();
203 event = trace_buffer_lock_reserve(blk_tr, TRACE_BLK,
204 sizeof(*t) + pdu_len,
205 0, pc);
206 if (!event)
207 return;
208 t = ring_buffer_event_data(event);
209 goto record_it;
210 }
211
212 /*
213 * A word about the locking here - we disable interrupts to reserve
214 * some space in the relay per-cpu buffer, to prevent an irq
215 * from coming in and stepping on our toes.
216 */
217 local_irq_save(flags);