Re: [PATCH] pcm_native: Remove VLA usage

From: kbuild test robot
Date: Thu Mar 29 2018 - 20:08:14 EST

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Hi Kyle,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on v4.16-rc7]
[cannot apply to sound/for-next next-20180329]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Kyle-Spiers/pcm_native-Remove-VLA-usage/20180330-073734
config: i386-randconfig-x075-201812 (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

All warnings (new ones prefixed by >>):

sound/core/pcm_native.c: In function 'constrain_params_by_rules':
>> sound/core/pcm_native.c:401:3: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
if (changed < 0)
^~
sound/core/pcm_native.c:403:4: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
return changed;
^~~~~~

vim +/if +401 sound/core/pcm_native.c

^1da177e4 Linus Torvalds 2005-04-16 319
9cc07f55d Takashi Sakamoto 2017-06-09 320 static int constrain_params_by_rules(struct snd_pcm_substream *substream,
877211f5e Takashi Iwai 2005-11-17 321 struct snd_pcm_hw_params *params)
^1da177e4 Linus Torvalds 2005-04-16 322 {
9cc07f55d Takashi Sakamoto 2017-06-09 323 struct snd_pcm_hw_constraints *constrs =
9cc07f55d Takashi Sakamoto 2017-06-09 324 &substream->runtime->hw_constraints;
^1da177e4 Linus Torvalds 2005-04-16 325 unsigned int k;
16c438ade Kyle Spiers 2018-03-28 326 unsigned int *rstamps;
^1da177e4 Linus Torvalds 2005-04-16 327 unsigned int vstamps[SNDRV_PCM_HW_PARAM_LAST_INTERVAL + 1];
d81052f92 Takashi Sakamoto 2017-06-09 328 unsigned int stamp;
a1c06e39a Takashi Sakamoto 2017-06-09 329 struct snd_pcm_hw_rule *r;
a1c06e39a Takashi Sakamoto 2017-06-09 330 unsigned int d;
9cc07f55d Takashi Sakamoto 2017-06-09 331 struct snd_mask old_mask;
9cc07f55d Takashi Sakamoto 2017-06-09 332 struct snd_interval old_interval;
a1c06e39a Takashi Sakamoto 2017-06-09 333 bool again;
9cc07f55d Takashi Sakamoto 2017-06-09 334 int changed;
^1da177e4 Linus Torvalds 2005-04-16 335
d81052f92 Takashi Sakamoto 2017-06-09 336 /*
d81052f92 Takashi Sakamoto 2017-06-09 337 * Each application of rule has own sequence number.
d81052f92 Takashi Sakamoto 2017-06-09 338 *
d81052f92 Takashi Sakamoto 2017-06-09 339 * Each member of 'rstamps' array represents the sequence number of
d81052f92 Takashi Sakamoto 2017-06-09 340 * recent application of corresponding rule.
d81052f92 Takashi Sakamoto 2017-06-09 341 */
16c438ade Kyle Spiers 2018-03-28 342
16c438ade Kyle Spiers 2018-03-28 343 rstamps = kcalloc(constrs->rules_num, sizeof(*rstamps), GFP_KERNEL);
d81052f92 Takashi Sakamoto 2017-06-09 344
d81052f92 Takashi Sakamoto 2017-06-09 345 /*
d81052f92 Takashi Sakamoto 2017-06-09 346 * Each member of 'vstamps' array represents the sequence number of
d81052f92 Takashi Sakamoto 2017-06-09 347 * recent application of rule in which corresponding parameters were
d81052f92 Takashi Sakamoto 2017-06-09 348 * changed.
d81052f92 Takashi Sakamoto 2017-06-09 349 *
d81052f92 Takashi Sakamoto 2017-06-09 350 * In initial state, elements corresponding to parameters requested by
d81052f92 Takashi Sakamoto 2017-06-09 351 * a caller is 1. For unrequested parameters, corresponding members
d81052f92 Takashi Sakamoto 2017-06-09 352 * have 0 so that the parameters are never changed anymore.
d81052f92 Takashi Sakamoto 2017-06-09 353 */
^1da177e4 Linus Torvalds 2005-04-16 354 for (k = 0; k <= SNDRV_PCM_HW_PARAM_LAST_INTERVAL; k++)
^1da177e4 Linus Torvalds 2005-04-16 355 vstamps[k] = (params->rmask & (1 << k)) ? 1 : 0;
d81052f92 Takashi Sakamoto 2017-06-09 356
d81052f92 Takashi Sakamoto 2017-06-09 357 /* Due to the above design, actual sequence number starts at 2. */
d81052f92 Takashi Sakamoto 2017-06-09 358 stamp = 2;
0d4e39996 Takashi Sakamoto 2017-06-09 359 retry:
d81052f92 Takashi Sakamoto 2017-06-09 360 /* Apply all rules in order. */
a1c06e39a Takashi Sakamoto 2017-06-09 361 again = false;
^1da177e4 Linus Torvalds 2005-04-16 362 for (k = 0; k < constrs->rules_num; k++) {
a1c06e39a Takashi Sakamoto 2017-06-09 363 r = &constrs->rules[k];
d81052f92 Takashi Sakamoto 2017-06-09 364
d81052f92 Takashi Sakamoto 2017-06-09 365 /*
d81052f92 Takashi Sakamoto 2017-06-09 366 * Check condition bits of this rule. When the rule has
d81052f92 Takashi Sakamoto 2017-06-09 367 * some condition bits, parameter without the bits is
d81052f92 Takashi Sakamoto 2017-06-09 368 * never processed. SNDRV_PCM_HW_PARAMS_NO_PERIOD_WAKEUP
d81052f92 Takashi Sakamoto 2017-06-09 369 * is an example of the condition bits.
d81052f92 Takashi Sakamoto 2017-06-09 370 */
^1da177e4 Linus Torvalds 2005-04-16 371 if (r->cond && !(r->cond & params->flags))
^1da177e4 Linus Torvalds 2005-04-16 372 continue;
d81052f92 Takashi Sakamoto 2017-06-09 373
d81052f92 Takashi Sakamoto 2017-06-09 374 /*
d81052f92 Takashi Sakamoto 2017-06-09 375 * The 'deps' array includes maximum three dependencies
d81052f92 Takashi Sakamoto 2017-06-09 376 * to SNDRV_PCM_HW_PARAM_XXXs for this rule. The fourth
d81052f92 Takashi Sakamoto 2017-06-09 377 * member of this array is a sentinel and should be
d81052f92 Takashi Sakamoto 2017-06-09 378 * negative value.
d81052f92 Takashi Sakamoto 2017-06-09 379 *
d81052f92 Takashi Sakamoto 2017-06-09 380 * This rule should be processed in this time when dependent
d81052f92 Takashi Sakamoto 2017-06-09 381 * parameters were changed at former applications of the other
d81052f92 Takashi Sakamoto 2017-06-09 382 * rules.
d81052f92 Takashi Sakamoto 2017-06-09 383 */
^1da177e4 Linus Torvalds 2005-04-16 384 for (d = 0; r->deps[d] >= 0; d++) {
d656b4a65 Takashi Sakamoto 2017-06-09 385 if (vstamps[r->deps[d]] > rstamps[k])
^1da177e4 Linus Torvalds 2005-04-16 386 break;
^1da177e4 Linus Torvalds 2005-04-16 387 }
d656b4a65 Takashi Sakamoto 2017-06-09 388 if (r->deps[d] < 0)
^1da177e4 Linus Torvalds 2005-04-16 389 continue;
be4e31dab Takashi Sakamoto 2017-06-07 390
be4e31dab Takashi Sakamoto 2017-06-07 391 if (trace_hw_mask_param_enabled()) {
be4e31dab Takashi Sakamoto 2017-06-07 392 if (hw_is_mask(r->var))
be4e31dab Takashi Sakamoto 2017-06-07 393 old_mask = *hw_param_mask(params, r->var);
^1da177e4 Linus Torvalds 2005-04-16 394 }
be4e31dab Takashi Sakamoto 2017-06-07 395 if (trace_hw_interval_param_enabled()) {
be4e31dab Takashi Sakamoto 2017-06-07 396 if (hw_is_interval(r->var))
be4e31dab Takashi Sakamoto 2017-06-07 397 old_interval = *hw_param_interval(params, r->var);
^1da177e4 Linus Torvalds 2005-04-16 398 }
c6706de0c Takashi Sakamoto 2017-06-07 399
^1da177e4 Linus Torvalds 2005-04-16 400 changed = r->func(params, r);
f74ae15fe Takashi Sakamoto 2017-06-11 @401 if (changed < 0)
16c438ade Kyle Spiers 2018-03-28 402 kfree(rstamps);
f74ae15fe Takashi Sakamoto 2017-06-11 403 return changed;
c6706de0c Takashi Sakamoto 2017-06-07 404
d81052f92 Takashi Sakamoto 2017-06-09 405 /*
82e7d5012 Takashi Sakamoto 2017-06-11 406 * When the parameter is changed, notify it to the caller
d81052f92 Takashi Sakamoto 2017-06-09 407 * by corresponding returned bit, then preparing for next
d81052f92 Takashi Sakamoto 2017-06-09 408 * iteration.
d81052f92 Takashi Sakamoto 2017-06-09 409 */
^1da177e4 Linus Torvalds 2005-04-16 410 if (changed && r->var >= 0) {
82e7d5012 Takashi Sakamoto 2017-06-11 411 if (hw_is_mask(r->var)) {
82e7d5012 Takashi Sakamoto 2017-06-11 412 trace_hw_mask_param(substream, r->var,
82e7d5012 Takashi Sakamoto 2017-06-11 413 k + 1, &old_mask,
82e7d5012 Takashi Sakamoto 2017-06-11 414 hw_param_mask(params, r->var));
^1da177e4 Linus Torvalds 2005-04-16 415 }
82e7d5012 Takashi Sakamoto 2017-06-11 416 if (hw_is_interval(r->var)) {
82e7d5012 Takashi Sakamoto 2017-06-11 417 trace_hw_interval_param(substream, r->var,
82e7d5012 Takashi Sakamoto 2017-06-11 418 k + 1, &old_interval,
82e7d5012 Takashi Sakamoto 2017-06-11 419 hw_param_interval(params, r->var));
^1da177e4 Linus Torvalds 2005-04-16 420 }
82e7d5012 Takashi Sakamoto 2017-06-11 421
^1da177e4 Linus Torvalds 2005-04-16 422 params->cmask |= (1 << r->var);
^1da177e4 Linus Torvalds 2005-04-16 423 vstamps[r->var] = stamp;
a1c06e39a Takashi Sakamoto 2017-06-09 424 again = true;
^1da177e4 Linus Torvalds 2005-04-16 425 }
f74ae15fe Takashi Sakamoto 2017-06-11 426
82e7d5012 Takashi Sakamoto 2017-06-11 427 rstamps[k] = stamp++;
^1da177e4 Linus Torvalds 2005-04-16 428 }
0d4e39996 Takashi Sakamoto 2017-06-09 429
d81052f92 Takashi Sakamoto 2017-06-09 430 /* Iterate to evaluate all rules till no parameters are changed. */
0d4e39996 Takashi Sakamoto 2017-06-09 431 if (again)
0d4e39996 Takashi Sakamoto 2017-06-09 432 goto retry;
9cc07f55d Takashi Sakamoto 2017-06-09 433
16c438ade Kyle Spiers 2018-03-28 434 kfree(rstamps);
9cc07f55d Takashi Sakamoto 2017-06-09 435 return 0;
^1da177e4 Linus Torvalds 2005-04-16 436 }
9cc07f55d Takashi Sakamoto 2017-06-09 437

:::::: The code at line 401 was first introduced by commit
:::::: f74ae15fe3da7905b78e986ad906a333587cf160 ALSA: pcm: return error immediately for parameters handling

:::::: TO: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
:::::: CC: Takashi Iwai <tiwai@xxxxxxx>

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Next message: Derek Robson: "Re: Regression in 4.16-rc7 - ipsec vpn broken"
Previous message: Bart Van Assche: "Re: [PATCH] scsi: Introduce sdev_printk_ratelimited to throttle frequent printk"
In reply to: Kees Cook: "Re: [PATCH] pcm_native: Remove VLA usage"
Next in thread: kbuild test robot: "Re: [PATCH] pcm_native: Remove VLA usage"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]