Re: [PATCH 1/1] eventfd new tag EFD_VPOLL: generate epoll events
From: kbuild test robot
Date: Sun May 26 2019 - 23:13:53 EST
Hi Renzo,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v5.2-rc2 next-20190524]
[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/Renzo-Davoli/eventfd-new-tag-EFD_VPOLL-generate-epoll-events/20190527-023620
reproduce:
# apt-get install sparse
# sparse version: v0.6.1-rc1-7-g2b96cd8-dirty
make ARCH=x86_64 allmodconfig
make C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__'
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
sparse warnings: (new ones prefixed by >>)
>> fs/eventfd.c:321:27: sparse: sparse: restricted __poll_t degrades to integer
>> fs/eventfd.c:321:16: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __poll_t [usertype] events @@ got poll_t [usertype] events @@
>> fs/eventfd.c:321:16: sparse: expected restricted __poll_t [usertype] events
>> fs/eventfd.c:321:16: sparse: got unsigned long long
fs/eventfd.c:357:25: sparse: sparse: restricted __poll_t degrades to integer
>> fs/eventfd.c:359:27: sparse: sparse: cast from restricted __poll_t
fs/eventfd.c:367:44: sparse: sparse: restricted __poll_t degrades to integer
>> fs/eventfd.c:375:17: sparse: sparse: cast to restricted __poll_t
>> fs/eventfd.c:512:28: sparse: sparse: invalid assignment: &=
>> fs/eventfd.c:512:28: sparse: left side has type unsigned long long
>> fs/eventfd.c:512:28: sparse: right side has type restricted __poll_t
vim +321 fs/eventfd.c
310
311 static __poll_t eventfd_vpoll_poll(struct file *file, poll_table *wait)
312 {
313 struct eventfd_ctx *ctx = file->private_data;
314 __poll_t events = 0;
315 u64 count;
316
317 poll_wait(file, &ctx->wqh, wait);
318
319 count = READ_ONCE(ctx->count);
320
> 321 events = (count & EPOLLALLMASK);
322
323 return events;
324 }
325
326 static ssize_t eventfd_vpoll_read(struct file *file, char __user *buf,
327 size_t count, loff_t *ppos)
328 {
329 struct eventfd_ctx *ctx = file->private_data;
330 ssize_t res;
331 __u64 ucnt = 0;
332
333 if (count < sizeof(ucnt))
334 return -EINVAL;
335 res = sizeof(ucnt);
336 ucnt = READ_ONCE(ctx->count);
337 if (put_user(ucnt, (__u64 __user *)buf))
338 return -EFAULT;
339
340 return res;
341 }
342
343 static ssize_t eventfd_vpoll_write(struct file *file, const char __user *buf,
344 size_t count, loff_t *ppos)
345 {
346 struct eventfd_ctx *ctx = file->private_data;
347 ssize_t res;
348 __u64 ucnt;
349 __u32 events;
350
351 if (count < sizeof(ucnt))
352 return -EINVAL;
353 if (copy_from_user(&ucnt, buf, sizeof(ucnt)))
354 return -EFAULT;
355 spin_lock_irq(&ctx->wqh.lock);
356
357 events = ucnt & EPOLLALLMASK;
358 res = sizeof(ucnt);
> 359 switch (ucnt & ~((__u64)EPOLLALLMASK)) {
360 case EFD_VPOLL_ADDEVENTS:
361 ctx->count |= events;
362 break;
363 case EFD_VPOLL_DELEVENTS:
364 ctx->count &= ~(events);
365 break;
366 case EFD_VPOLL_MODEVENTS:
367 ctx->count = (ctx->count & ~EPOLLALLMASK) | events;
368 break;
369 default:
370 res = -EINVAL;
371 }
372
373 /* wake up waiting threads */
374 if (res >= 0 && waitqueue_active(&ctx->wqh))
> 375 wake_up_locked_poll(&ctx->wqh, res);
376
377 spin_unlock_irq(&ctx->wqh.lock);
378
379 return res;
380
381 }
382
383 #ifdef CONFIG_PROC_FS
384 static void eventfd_show_fdinfo(struct seq_file *m, struct file *f)
385 {
386 struct eventfd_ctx *ctx = f->private_data;
387
388 spin_lock_irq(&ctx->wqh.lock);
389 seq_printf(m, "eventfd-count: %16llx\n",
390 (unsigned long long)ctx->count);
391 spin_unlock_irq(&ctx->wqh.lock);
392 seq_printf(m, "eventfd-id: %d\n", ctx->id);
393 }
394 #endif
395
396 static const struct file_operations eventfd_fops = {
397 #ifdef CONFIG_PROC_FS
398 .show_fdinfo = eventfd_show_fdinfo,
399 #endif
400 .release = eventfd_release,
401 .poll = eventfd_poll,
402 .read = eventfd_read,
403 .write = eventfd_write,
404 .llseek = noop_llseek,
405 };
406
407 static const struct file_operations eventfd_vpoll_fops = {
408 #ifdef CONFIG_PROC_FS
409 .show_fdinfo = eventfd_show_fdinfo,
410 #endif
411 .release = eventfd_release,
412 .poll = eventfd_vpoll_poll,
413 .read = eventfd_vpoll_read,
414 .write = eventfd_vpoll_write,
415 .llseek = noop_llseek,
416 };
417
418 /**
419 * eventfd_fget - Acquire a reference of an eventfd file descriptor.
420 * @fd: [in] Eventfd file descriptor.
421 *
422 * Returns a pointer to the eventfd file structure in case of success, or the
423 * following error pointer:
424 *
425 * -EBADF : Invalid @fd file descriptor.
426 * -EINVAL : The @fd file descriptor is not an eventfd file.
427 */
428 struct file *eventfd_fget(int fd)
429 {
430 struct file *file;
431
432 file = fget(fd);
433 if (!file)
434 return ERR_PTR(-EBADF);
435 if (file->f_op != &eventfd_fops) {
436 fput(file);
437 return ERR_PTR(-EINVAL);
438 }
439
440 return file;
441 }
442 EXPORT_SYMBOL_GPL(eventfd_fget);
443
444 /**
445 * eventfd_ctx_fdget - Acquires a reference to the internal eventfd context.
446 * @fd: [in] Eventfd file descriptor.
447 *
448 * Returns a pointer to the internal eventfd context, otherwise the error
449 * pointers returned by the following functions:
450 *
451 * eventfd_fget
452 */
453 struct eventfd_ctx *eventfd_ctx_fdget(int fd)
454 {
455 struct eventfd_ctx *ctx;
456 struct fd f = fdget(fd);
457 if (!f.file)
458 return ERR_PTR(-EBADF);
459 ctx = eventfd_ctx_fileget(f.file);
460 fdput(f);
461 return ctx;
462 }
463 EXPORT_SYMBOL_GPL(eventfd_ctx_fdget);
464
465 /**
466 * eventfd_ctx_fileget - Acquires a reference to the internal eventfd context.
467 * @file: [in] Eventfd file pointer.
468 *
469 * Returns a pointer to the internal eventfd context, otherwise the error
470 * pointer:
471 *
472 * -EINVAL : The @fd file descriptor is not an eventfd file.
473 */
474 struct eventfd_ctx *eventfd_ctx_fileget(struct file *file)
475 {
476 struct eventfd_ctx *ctx;
477
478 if (file->f_op != &eventfd_fops)
479 return ERR_PTR(-EINVAL);
480
481 ctx = file->private_data;
482 kref_get(&ctx->kref);
483 return ctx;
484 }
485 EXPORT_SYMBOL_GPL(eventfd_ctx_fileget);
486
487 static int do_eventfd(unsigned int count, int flags)
488 {
489 struct eventfd_ctx *ctx;
490 const struct file_operations *fops = &eventfd_fops;
491 int fd;
492
493 /* Check the EFD_* constants for consistency. */
494 BUILD_BUG_ON(EFD_CLOEXEC != O_CLOEXEC);
495 BUILD_BUG_ON(EFD_NONBLOCK != O_NONBLOCK);
496
497 if (flags & ~EFD_FLAGS_SET)
498 return -EINVAL;
499
500 ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
501 if (!ctx)
502 return -ENOMEM;
503
504 kref_init(&ctx->kref);
505 init_waitqueue_head(&ctx->wqh);
506 ctx->count = count;
507 ctx->flags = flags;
508 ctx->id = ida_simple_get(&eventfd_ida, 0, 0, GFP_KERNEL);
509
510 if (flags & EFD_VPOLL) {
511 fops = &eventfd_vpoll_fops;
> 512 ctx->count &= EPOLLALLMASK;
513 }
514 fd = anon_inode_getfd("[eventfd]", fops, ctx,
515 O_RDWR | (flags & EFD_SHARED_FCNTL_FLAGS));
516 if (fd < 0)
517 eventfd_free_ctx(ctx);
518
519 return fd;
520 }
521
---
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