ia64/linux-2.6.18-xen.hg

view block/blktrace.c @ 890:2e94884f0e8d

Dom0 PCI: fix a regression introduced by the SR-IOV change

The device class may be changed during the early fixup. So need to
re-read the device class from pci_dev after the fixup.

The patch "PCI: centralize device setup code" (c/s 825) wrongly
cleaned up the device class re-read. This patch reverts that change.

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
author Keir Fraser <keir.fraser@citrix.com>
date Wed Jun 03 11:21:52 2009 +0100 (2009-06-03)
parents 831230e53067
children
line source
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@suse.de>
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 <asm/uaccess.h>
27 static DEFINE_PER_CPU(unsigned long long, blk_trace_cpu_offset) = { 0, };
28 static unsigned int blktrace_seq __read_mostly = 1;
30 /*
31 * Send out a notify for this process, if we haven't done so since a trace
32 * started
33 */
34 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
35 {
36 struct blk_io_trace *t;
38 t = relay_reserve(bt->rchan, sizeof(*t) + sizeof(tsk->comm));
39 if (t) {
40 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
41 t->device = bt->dev;
42 t->action = BLK_TC_ACT(BLK_TC_NOTIFY);
43 t->pid = tsk->pid;
44 t->cpu = smp_processor_id();
45 t->pdu_len = sizeof(tsk->comm);
46 memcpy((void *) t + sizeof(*t), tsk->comm, t->pdu_len);
47 tsk->btrace_seq = blktrace_seq;
48 }
49 }
51 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
52 pid_t pid)
53 {
54 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
55 return 1;
56 if (sector < bt->start_lba || sector > bt->end_lba)
57 return 1;
58 if (bt->pid && pid != bt->pid)
59 return 1;
61 return 0;
62 }
64 /*
65 * Data direction bit lookup
66 */
67 static u32 ddir_act[2] __read_mostly = { BLK_TC_ACT(BLK_TC_READ), BLK_TC_ACT(BLK_TC_WRITE) };
69 /*
70 * Bio action bits of interest
71 */
72 static u32 bio_act[5] __read_mostly = { 0, BLK_TC_ACT(BLK_TC_BARRIER), BLK_TC_ACT(BLK_TC_SYNC), 0, BLK_TC_ACT(BLK_TC_AHEAD) };
74 /*
75 * More could be added as needed, taking care to increment the decrementer
76 * to get correct indexing
77 */
78 #define trace_barrier_bit(rw) \
79 (((rw) & (1 << BIO_RW_BARRIER)) >> (BIO_RW_BARRIER - 0))
80 #define trace_sync_bit(rw) \
81 (((rw) & (1 << BIO_RW_SYNC)) >> (BIO_RW_SYNC - 1))
82 #define trace_ahead_bit(rw) \
83 (((rw) & (1 << BIO_RW_AHEAD)) << (2 - BIO_RW_AHEAD))
85 /*
86 * The worker for the various blk_add_trace*() types. Fills out a
87 * blk_io_trace structure and places it in a per-cpu subbuffer.
88 */
89 void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
90 int rw, u32 what, int error, int pdu_len, void *pdu_data)
91 {
92 struct task_struct *tsk = current;
93 struct blk_io_trace *t;
94 unsigned long flags;
95 unsigned long *sequence;
96 pid_t pid;
97 int cpu;
99 if (unlikely(bt->trace_state != Blktrace_running))
100 return;
102 what |= ddir_act[rw & WRITE];
103 what |= bio_act[trace_barrier_bit(rw)];
104 what |= bio_act[trace_sync_bit(rw)];
105 what |= bio_act[trace_ahead_bit(rw)];
107 pid = tsk->pid;
108 if (unlikely(act_log_check(bt, what, sector, pid)))
109 return;
111 /*
112 * A word about the locking here - we disable interrupts to reserve
113 * some space in the relay per-cpu buffer, to prevent an irq
114 * from coming in and stepping on our toes. Once reserved, it's
115 * enough to get preemption disabled to prevent read of this data
116 * before we are through filling it. get_cpu()/put_cpu() does this
117 * for us
118 */
119 local_irq_save(flags);
121 if (unlikely(tsk->btrace_seq != blktrace_seq))
122 trace_note_tsk(bt, tsk);
124 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
125 if (t) {
126 cpu = smp_processor_id();
127 sequence = per_cpu_ptr(bt->sequence, cpu);
129 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
130 t->sequence = ++(*sequence);
131 t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
132 t->sector = sector;
133 t->bytes = bytes;
134 t->action = what;
135 t->pid = pid;
136 t->device = bt->dev;
137 t->cpu = cpu;
138 t->error = error;
139 t->pdu_len = pdu_len;
141 if (pdu_len)
142 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
143 }
145 local_irq_restore(flags);
146 }
148 EXPORT_SYMBOL_GPL(__blk_add_trace);
150 static struct dentry *blk_tree_root;
151 static struct mutex blk_tree_mutex;
152 static unsigned int root_users;
154 static inline void blk_remove_root(void)
155 {
156 if (blk_tree_root) {
157 debugfs_remove(blk_tree_root);
158 blk_tree_root = NULL;
159 }
160 }
162 static void blk_remove_tree(struct dentry *dir)
163 {
164 mutex_lock(&blk_tree_mutex);
165 debugfs_remove(dir);
166 if (--root_users == 0)
167 blk_remove_root();
168 mutex_unlock(&blk_tree_mutex);
169 }
171 static struct dentry *blk_create_tree(const char *blk_name)
172 {
173 struct dentry *dir = NULL;
175 mutex_lock(&blk_tree_mutex);
177 if (!blk_tree_root) {
178 blk_tree_root = debugfs_create_dir("block", NULL);
179 if (!blk_tree_root)
180 goto err;
181 }
183 dir = debugfs_create_dir(blk_name, blk_tree_root);
184 if (dir)
185 root_users++;
186 else
187 blk_remove_root();
189 err:
190 mutex_unlock(&blk_tree_mutex);
191 return dir;
192 }
194 static void blk_trace_cleanup(struct blk_trace *bt)
195 {
196 relay_close(bt->rchan);
197 debugfs_remove(bt->dropped_file);
198 blk_remove_tree(bt->dir);
199 free_percpu(bt->sequence);
200 kfree(bt);
201 }
203 static int blk_trace_remove(request_queue_t *q)
204 {
205 struct blk_trace *bt;
207 bt = xchg(&q->blk_trace, NULL);
208 if (!bt)
209 return -EINVAL;
211 if (bt->trace_state == Blktrace_setup ||
212 bt->trace_state == Blktrace_stopped)
213 blk_trace_cleanup(bt);
215 return 0;
216 }
218 static int blk_dropped_open(struct inode *inode, struct file *filp)
219 {
220 filp->private_data = inode->u.generic_ip;
222 return 0;
223 }
225 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
226 size_t count, loff_t *ppos)
227 {
228 struct blk_trace *bt = filp->private_data;
229 char buf[16];
231 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
233 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
234 }
236 static struct file_operations blk_dropped_fops = {
237 .owner = THIS_MODULE,
238 .open = blk_dropped_open,
239 .read = blk_dropped_read,
240 };
242 /*
243 * Keep track of how many times we encountered a full subbuffer, to aid
244 * the user space app in telling how many lost events there were.
245 */
246 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
247 void *prev_subbuf, size_t prev_padding)
248 {
249 struct blk_trace *bt;
251 if (!relay_buf_full(buf))
252 return 1;
254 bt = buf->chan->private_data;
255 atomic_inc(&bt->dropped);
256 return 0;
257 }
259 static int blk_remove_buf_file_callback(struct dentry *dentry)
260 {
261 debugfs_remove(dentry);
262 return 0;
263 }
265 static struct dentry *blk_create_buf_file_callback(const char *filename,
266 struct dentry *parent,
267 int mode,
268 struct rchan_buf *buf,
269 int *is_global)
270 {
271 return debugfs_create_file(filename, mode, parent, buf,
272 &relay_file_operations);
273 }
275 static struct rchan_callbacks blk_relay_callbacks = {
276 .subbuf_start = blk_subbuf_start_callback,
277 .create_buf_file = blk_create_buf_file_callback,
278 .remove_buf_file = blk_remove_buf_file_callback,
279 };
281 /*
282 * Setup everything required to start tracing
283 */
284 static int blk_trace_setup(request_queue_t *q, struct block_device *bdev,
285 char __user *arg)
286 {
287 struct blk_user_trace_setup buts;
288 struct blk_trace *old_bt, *bt = NULL;
289 struct dentry *dir = NULL;
290 char b[BDEVNAME_SIZE];
291 int ret, i;
293 if (copy_from_user(&buts, arg, sizeof(buts)))
294 return -EFAULT;
296 if (!buts.buf_size || !buts.buf_nr)
297 return -EINVAL;
299 strcpy(buts.name, bdevname(bdev, b));
301 /*
302 * some device names have larger paths - convert the slashes
303 * to underscores for this to work as expected
304 */
305 for (i = 0; i < strlen(buts.name); i++)
306 if (buts.name[i] == '/')
307 buts.name[i] = '_';
309 if (copy_to_user(arg, &buts, sizeof(buts)))
310 return -EFAULT;
312 ret = -ENOMEM;
313 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
314 if (!bt)
315 goto err;
317 bt->sequence = alloc_percpu(unsigned long);
318 if (!bt->sequence)
319 goto err;
321 ret = -ENOENT;
322 dir = blk_create_tree(buts.name);
323 if (!dir)
324 goto err;
326 bt->dir = dir;
327 bt->dev = bdev->bd_dev;
328 atomic_set(&bt->dropped, 0);
330 ret = -EIO;
331 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt, &blk_dropped_fops);
332 if (!bt->dropped_file)
333 goto err;
335 bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks);
336 if (!bt->rchan)
337 goto err;
338 bt->rchan->private_data = bt;
340 bt->act_mask = buts.act_mask;
341 if (!bt->act_mask)
342 bt->act_mask = (u16) -1;
344 bt->start_lba = buts.start_lba;
345 bt->end_lba = buts.end_lba;
346 if (!bt->end_lba)
347 bt->end_lba = -1ULL;
349 bt->pid = buts.pid;
350 bt->trace_state = Blktrace_setup;
352 ret = -EBUSY;
353 old_bt = xchg(&q->blk_trace, bt);
354 if (old_bt) {
355 (void) xchg(&q->blk_trace, old_bt);
356 goto err;
357 }
359 return 0;
360 err:
361 if (dir)
362 blk_remove_tree(dir);
363 if (bt) {
364 if (bt->dropped_file)
365 debugfs_remove(bt->dropped_file);
366 if (bt->sequence)
367 free_percpu(bt->sequence);
368 if (bt->rchan)
369 relay_close(bt->rchan);
370 kfree(bt);
371 }
372 return ret;
373 }
375 static int blk_trace_startstop(request_queue_t *q, int start)
376 {
377 struct blk_trace *bt;
378 int ret;
380 if ((bt = q->blk_trace) == NULL)
381 return -EINVAL;
383 /*
384 * For starting a trace, we can transition from a setup or stopped
385 * trace. For stopping a trace, the state must be running
386 */
387 ret = -EINVAL;
388 if (start) {
389 if (bt->trace_state == Blktrace_setup ||
390 bt->trace_state == Blktrace_stopped) {
391 blktrace_seq++;
392 smp_mb();
393 bt->trace_state = Blktrace_running;
394 ret = 0;
395 }
396 } else {
397 if (bt->trace_state == Blktrace_running) {
398 bt->trace_state = Blktrace_stopped;
399 relay_flush(bt->rchan);
400 ret = 0;
401 }
402 }
404 return ret;
405 }
407 /**
408 * blk_trace_ioctl: - handle the ioctls associated with tracing
409 * @bdev: the block device
410 * @cmd: the ioctl cmd
411 * @arg: the argument data, if any
412 *
413 **/
414 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
415 {
416 request_queue_t *q;
417 int ret, start = 0;
419 q = bdev_get_queue(bdev);
420 if (!q)
421 return -ENXIO;
423 mutex_lock(&bdev->bd_mutex);
425 switch (cmd) {
426 case BLKTRACESETUP:
427 ret = blk_trace_setup(q, bdev, arg);
428 break;
429 case BLKTRACESTART:
430 start = 1;
431 case BLKTRACESTOP:
432 ret = blk_trace_startstop(q, start);
433 break;
434 case BLKTRACETEARDOWN:
435 ret = blk_trace_remove(q);
436 break;
437 default:
438 ret = -ENOTTY;
439 break;
440 }
442 mutex_unlock(&bdev->bd_mutex);
443 return ret;
444 }
446 /**
447 * blk_trace_shutdown: - stop and cleanup trace structures
448 * @q: the request queue associated with the device
449 *
450 **/
451 void blk_trace_shutdown(request_queue_t *q)
452 {
453 blk_trace_startstop(q, 0);
454 blk_trace_remove(q);
455 }
457 /*
458 * Average offset over two calls to sched_clock() with a gettimeofday()
459 * in the middle
460 */
461 static void blk_check_time(unsigned long long *t)
462 {
463 unsigned long long a, b;
464 struct timeval tv;
466 a = sched_clock();
467 do_gettimeofday(&tv);
468 b = sched_clock();
470 *t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
471 *t -= (a + b) / 2;
472 }
474 static void blk_trace_check_cpu_time(void *data)
475 {
476 unsigned long long *t;
477 int cpu = get_cpu();
479 t = &per_cpu(blk_trace_cpu_offset, cpu);
481 /*
482 * Just call it twice, hopefully the second call will be cache hot
483 * and a little more precise
484 */
485 blk_check_time(t);
486 blk_check_time(t);
488 put_cpu();
489 }
491 /*
492 * Call blk_trace_check_cpu_time() on each CPU to calibrate our inter-CPU
493 * timings
494 */
495 static void blk_trace_calibrate_offsets(void)
496 {
497 unsigned long flags;
499 smp_call_function(blk_trace_check_cpu_time, NULL, 1, 1);
500 local_irq_save(flags);
501 blk_trace_check_cpu_time(NULL);
502 local_irq_restore(flags);
503 }
505 static void blk_trace_set_ht_offsets(void)
506 {
507 #if defined(CONFIG_SCHED_SMT)
508 int cpu, i;
510 /*
511 * now make sure HT siblings have the same time offset
512 */
513 preempt_disable();
514 for_each_online_cpu(cpu) {
515 unsigned long long *cpu_off, *sibling_off;
517 for_each_cpu_mask(i, cpu_sibling_map[cpu]) {
518 if (i == cpu)
519 continue;
521 cpu_off = &per_cpu(blk_trace_cpu_offset, cpu);
522 sibling_off = &per_cpu(blk_trace_cpu_offset, i);
523 *sibling_off = *cpu_off;
524 }
525 }
526 preempt_enable();
527 #endif
528 }
530 static __init int blk_trace_init(void)
531 {
532 mutex_init(&blk_tree_mutex);
533 blk_trace_calibrate_offsets();
534 blk_trace_set_ht_offsets();
536 return 0;
537 }
539 module_init(blk_trace_init);