[kbuild-all] Re: [PATCH] uio: Replace mutex info_lock with percpu_ref to improve performance

Hi Guixin, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on char-misc/char-misc-testing] [also build test WARNING on v5.17-rc3 next-20220208] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Guixin-Liu/uio-Replace-mutex-inf... base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git b86f32951d173b43d1db8de883473fc53dc3c772 config: parisc-randconfig-s032-20220208 (https://download.01.org/0day-ci/archive/20220208/202202082111.R18zUEHK-lk...) compiler: hppa-linux-gcc (GCC) 11.2.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/271c7d04f21a7c880e9dfb056eca51835... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Guixin-Liu/uio-Replace-mutex-info_lock-with-percpu_ref-to-improve-performance/20220208-152119 git checkout 271c7d04f21a7c880e9dfb056eca51835576833d # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=parisc SHELL=/bin/bash drivers/uio/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) drivers/uio/uio.c:564:24: sparse: expected restricted __poll_t drivers/uio/uio.c:564:24: sparse: got int drivers/uio/uio.c:567:21: sparse: sparse: incorrect type in assignment (different base types) @@ expected restricted __poll_t [usertype] ret @@ got int @@ drivers/uio/uio.c:567:21: sparse: expected restricted __poll_t [usertype] ret drivers/uio/uio.c:567:21: sparse: got int drivers/uio/uio.c:699:24: sparse: expected restricted vm_fault_t drivers/uio/uio.c:699:24: sparse: got int vim +564 drivers/uio/uio.c 556 557 static __poll_t uio_poll(struct file *filep, poll_table *wait) 558 { 559 struct uio_listener *listener = filep->private_data; 560 struct uio_device *idev = listener->dev; 561 __poll_t ret = 0; 562 563 if (!percpu_ref_tryget_live(&idev->info_ref)) 565 566 if (!idev->info || !idev->info->irq) 567 ret = -EIO; 568 percpu_ref_put(&idev->info_ref); 569 570 if (ret) 571 return ret; 572 573 poll_wait(filep, &idev->wait, wait); 574 if (listener->event_count != atomic_read(&idev->event)) 575 return EPOLLIN | EPOLLRDNORM; 576 return 0; 577 } 578 579 static ssize_t uio_read(struct file *filep, char __user *buf, 580 size_t count, loff_t *ppos) 581 { 582 struct uio_listener *listener = filep->private_data; 583 struct uio_device *idev = listener->dev; 584 DECLARE_WAITQUEUE(wait, current); 585 ssize_t retval = 0; 586 s32 event_count; 587 588 if (count != sizeof(s32)) 589 return -EINVAL; 590 591 add_wait_queue(&idev->wait, &wait); 592 593 do { 594 if (!percpu_ref_tryget_live(&idev->info_ref)) { 595 retval = -EINVAL; 596 break; 597 } 598 599 if (!idev->info || !idev->info->irq) { 600 retval = -EIO; 601 percpu_ref_put(&idev->info_ref); 602 break; 603 } 604 percpu_ref_put(&idev->info_ref); 605 606 set_current_state(TASK_INTERRUPTIBLE); 607 608 event_count = atomic_read(&idev->event); 609 if (event_count != listener->event_count) { 610 __set_current_state(TASK_RUNNING); 611 if (copy_to_user(buf, &event_count, count)) 612 retval = -EFAULT; 613 else { 614 listener->event_count = event_count; 615 retval = count; 616 } 617 break; 618 } 619 620 if (filep->f_flags & O_NONBLOCK) { 621 retval = -EAGAIN; 622 break; 623 } 624 625 if (signal_pending(current)) { 626 retval = -ERESTARTSYS; 627 break; 628 } 629 schedule(); 630 } while (1); 631 632 __set_current_state(TASK_RUNNING); 633 remove_wait_queue(&idev->wait, &wait); 634 635 return retval; 636 } 637 638 static ssize_t uio_write(struct file *filep, const char __user *buf, 639 size_t count, loff_t *ppos) 640 { 641 struct uio_listener *listener = filep->private_data; 642 struct uio_device *idev = listener->dev; 643 ssize_t retval; 644 s32 irq_on; 645 646 if (count != sizeof(s32)) 647 return -EINVAL; 648 649 if (copy_from_user(&irq_on, buf, count)) 650 return -EFAULT; 651 652 if (!percpu_ref_tryget_live(&idev->info_ref)) 653 return -EINVAL; 654 655 if (!idev->info) { 656 retval = -EINVAL; 657 goto out; 658 } 659 660 if (!idev->info->irq) { 661 retval = -EIO; 662 goto out; 663 } 664 665 if (!idev->info->irqcontrol) { 666 retval = -ENOSYS; 667 goto out; 668 } 669 670 retval = idev->info->irqcontrol(idev->info, irq_on); 671 672 out: 673 percpu_ref_put(&idev->info_ref); 674 return retval ? retval : sizeof(s32); 675 } 676 677 static int uio_find_mem_index(struct vm_area_struct *vma) 678 { 679 struct uio_device *idev = vma->vm_private_data; 680 681 if (vma->vm_pgoff < MAX_UIO_MAPS) { 682 if (idev->info->mem[vma->vm_pgoff].size == 0) 683 return -1; 684 return (int)vma->vm_pgoff; 685 } 686 return -1; 687 } 688 689 static vm_fault_t uio_vma_fault(struct vm_fault *vmf) 690 { 691 struct uio_device *idev = vmf->vma->vm_private_data; 692 struct page *page; 693 unsigned long offset; 694 void *addr; 695 vm_fault_t ret = 0; 696 int mi; 697 698 if (!percpu_ref_tryget_live(&idev->info_ref)) 700 701 if (!idev->info) { 702 ret = VM_FAULT_SIGBUS; 703 goto out; 704 } 705 706 mi = uio_find_mem_index(vmf->vma); 707 if (mi < 0) { 708 ret = VM_FAULT_SIGBUS; 709 goto out; 710 } 711 712 /* 713 * We need to subtract mi because userspace uses offset = N*PAGE_SIZE 714 * to use mem[N]. 715 */ 716 offset = (vmf->pgoff - mi) << PAGE_SHIFT; 717 718 addr = (void *)(unsigned long)idev->info->mem[mi].addr + offset; 719 if (idev->info->mem[mi].memtype == UIO_MEM_LOGICAL) 720 page = virt_to_page(addr); 721 else 722 page = vmalloc_to_page(addr); 723 get_page(page); 724 vmf->page = page; 725 726 out: 727 percpu_ref_put(&idev->info_ref); 728 return ret; 729 } 730 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org