Re: [PATCH] RDMA/umem: minor bug fix and cleanup in error handling paths

kbuild test robot
2019-03-02T16:03:43Z

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Hi John,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on rdma/for-next]
[also build test ERROR on v5.0-rc8 next-20190301]
[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/john-hubbard-gmail-com/RDMA-umem-minor-bug-fix-and-cleanup-in-error-handling-paths/20190302-233314
base: https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git for-next
config: i386-randconfig-x002-201908 (attached as .config)
compiler: gcc-8 (Debian 8.2.0-20) 8.2.0
reproduce:
# save the attached .config to linux build tree
make ARCH=i386

All errors (new ones prefixed by >>):

drivers/infiniband/core/umem_odp.c: In function 'ib_umem_odp_map_dma_pages':
>> drivers/infiniband/core/umem_odp.c:684:4: error: implicit declaration of function 'release_pages'; did you mean 'release_task'? [-Werror=implicit-function-declaration]
release_pages(&local_page_list[j], npages - j);
^~~~~~~~~~~~~
release_task
cc1: some warnings being treated as errors

vim +684 drivers/infiniband/core/umem_odp.c

559
560 /**
561 * ib_umem_odp_map_dma_pages - Pin and DMA map userspace memory in an ODP MR.
562 *
563 * Pins the range of pages passed in the argument, and maps them to
564 * DMA addresses. The DMA addresses of the mapped pages is updated in
565 * umem_odp->dma_list.
566 *
567 * Returns the number of pages mapped in success, negative error code
568 * for failure.
569 * An -EAGAIN error code is returned when a concurrent mmu notifier prevents
570 * the function from completing its task.
571 * An -ENOENT error code indicates that userspace process is being terminated
572 * and mm was already destroyed.
573 * @umem_odp: the umem to map and pin
574 * @user_virt: the address from which we need to map.
575 * @bcnt: the minimal number of bytes to pin and map. The mapping might be
576 * bigger due to alignment, and may also be smaller in case of an error
577 * pinning or mapping a page. The actual pages mapped is returned in
578 * the return value.
579 * @access_mask: bit mask of the requested access permissions for the given
580 * range.
581 * @current_seq: the MMU notifiers sequance value for synchronization with
582 * invalidations. the sequance number is read from
583 * umem_odp->notifiers_seq before calling this function
584 */
585 int ib_umem_odp_map_dma_pages(struct ib_umem_odp *umem_odp, u64 user_virt,
586 u64 bcnt, u64 access_mask,
587 unsigned long current_seq)
588 {
589 struct ib_umem *umem = &umem_odp->umem;
590 struct task_struct *owning_process = NULL;
591 struct mm_struct *owning_mm = umem_odp->umem.owning_mm;
592 struct page **local_page_list = NULL;
593 u64 page_mask, off;
594 int j, k, ret = 0, start_idx, npages = 0, page_shift;
595 unsigned int flags = 0;
596 phys_addr_t p = 0;
597
598 if (access_mask == 0)
599 return -EINVAL;
600
601 if (user_virt < ib_umem_start(umem) ||
602 user_virt + bcnt > ib_umem_end(umem))
603 return -EFAULT;
604
605 local_page_list = (struct page **)__get_free_page(GFP_KERNEL);
606 if (!local_page_list)
607 return -ENOMEM;
608
609 page_shift = umem->page_shift;
610 page_mask = ~(BIT(page_shift) - 1);
611 off = user_virt & (~page_mask);
612 user_virt = user_virt & page_mask;
613 bcnt += off; /* Charge for the first page offset as well. */
614
615 /*
616 * owning_process is allowed to be NULL, this means somehow the mm is
617 * existing beyond the lifetime of the originating process.. Presumably
618 * mmget_not_zero will fail in this case.
619 */
620 owning_process = get_pid_task(umem_odp->per_mm->tgid, PIDTYPE_PID);
621 if (WARN_ON(!mmget_not_zero(umem_odp->umem.owning_mm))) {
622 ret = -EINVAL;
623 goto out_put_task;
624 }
625
626 if (access_mask & ODP_WRITE_ALLOWED_BIT)
627 flags |= FOLL_WRITE;
628
629 start_idx = (user_virt - ib_umem_start(umem)) >> page_shift;
630 k = start_idx;
631
632 while (bcnt > 0) {
633 const size_t gup_num_pages = min_t(size_t,
634 (bcnt + BIT(page_shift) - 1) >> page_shift,
635 PAGE_SIZE / sizeof(struct page *));
636
637 down_read(&owning_mm->mmap_sem);
638 /*
639 * Note: this might result in redundent page getting. We can
640 * avoid this by checking dma_list to be 0 before calling
641 * get_user_pages. However, this make the code much more
642 * complex (and doesn't gain us much performance in most use
643 * cases).
644 */
645 npages = get_user_pages_remote(owning_process, owning_mm,
646 user_virt, gup_num_pages,
647 flags, local_page_list, NULL, NULL);
648 up_read(&owning_mm->mmap_sem);
649
650 if (npages < 0) {
651 if (npages != -EAGAIN)
652 pr_warn("fail to get %zu user pages with error %d\n",
653 gup_num_pages, npages);
654 else
655 pr_debug("fail to get %zu user pages with error %d\n",
656 gup_num_pages, npages);
657 break;
658 }
659
660 bcnt -= min_t(size_t, npages << PAGE_SHIFT, bcnt);
661 mutex_lock(&umem_odp->umem_mutex);
662 for (j = 0; j < npages; j++, user_virt += PAGE_SIZE) {
663 ret = ib_umem_odp_map_dma_single_page(
664 umem_odp, k, local_page_list[j],
665 access_mask, current_seq);
666 if (ret < 0) {
667 if (ret != -EAGAIN)
668 pr_warn("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
669 else
670 pr_debug("ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
671 break;
672 }
673
674 p = page_to_phys(local_page_list[j]);
675 k++;
676 }
677 mutex_unlock(&umem_odp->umem_mutex);
678
679 if (ret < 0) {
680 /*
681 * Release pages, starting at the the first page
682 * that experienced an error.
683 */
> 684 release_pages(&local_page_list[j], npages - j);
685 break;
686 }
687 }
688
689 if (ret >= 0) {
690 if (npages < 0 && k == start_idx)
691 ret = npages;
692 else
693 ret = k - start_idx;
694 }
695
696 mmput(owning_mm);
697 out_put_task:
698 if (owning_process)
699 put_task_struct(owning_process);
700 free_page((unsigned long)local_page_list);
701 return ret;
702 }
703 EXPORT_SYMBOL(ib_umem_odp_map_dma_pages);
704

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