From: Ralph Campbell <rcampbell@xxxxxxxxxx> Subject: lib/test_hmm.c: remove unused dmirror_zero_page The variable dmirror_zero_page is unused in the HMM self test driver which was probably intended to demonstrate how a driver could use migrate_vma_setup() to share a single read-only device private zero page similar to how the CPU does. However, this isn't needed for the self tests so remove it. Link: https://lkml.kernel.org/r/20200914213801.16520-1-rcampbell@xxxxxxxxxx Signed-off-by: Ralph Campbell <rcampbell@xxxxxxxxxx> Cc: Jerome Glisse <jglisse@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/test_hmm.c | 14 -------------- 1 file changed, 14 deletions(-) --- a/lib/test_hmm.c~hmm-test-remove-unused-dmirror_zero_page +++ a/lib/test_hmm.c @@ -36,7 +36,6 @@ static const struct dev_pagemap_ops dmirror_devmem_ops; static const struct mmu_interval_notifier_ops dmirror_min_ops; static dev_t dmirror_dev; -static struct page *dmirror_zero_page; struct dmirror_device; @@ -1127,17 +1126,6 @@ static int __init hmm_dmirror_init(void) goto err_chrdev; } - /* - * Allocate a zero page to simulate a reserved page of device private - * memory which is always zero. The zero_pfn page isn't used just to - * make the code here simpler (i.e., we need a struct page for it). - */ - dmirror_zero_page = alloc_page(GFP_HIGHUSER | __GFP_ZERO); - if (!dmirror_zero_page) { - ret = -ENOMEM; - goto err_chrdev; - } - pr_info("HMM test module loaded. This is only for testing HMM.\n"); return 0; @@ -1153,8 +1141,6 @@ static void __exit hmm_dmirror_exit(void { int id; - if (dmirror_zero_page) - __free_page(dmirror_zero_page); for (id = 0; id < DMIRROR_NDEVICES; id++) dmirror_device_remove(dmirror_devices + id); unregister_chrdev_region(dmirror_dev, DMIRROR_NDEVICES); _
