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authorLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 23:53:37 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 23:53:37 +0300
commitac73e3dc8acd0a3be292755db30388c3580f5674 (patch)
tree5abef6cb82b205b5dbbb69dca950b8a5aae716de /mm/highmem.c
parent148842c98a24e508aecb929718818fbf4c2a6ff3 (diff)
parentdfefd226b0bf7c435a58d75a0ce2f9273b9825f6 (diff)
downloadlinux-ac73e3dc8acd0a3be292755db30388c3580f5674.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: - a few random little subsystems - almost all of the MM patches which are staged ahead of linux-next material. I'll trickle to post-linux-next work in as the dependents get merged up. Subsystems affected by this patch series: kthread, kbuild, ide, ntfs, ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation, kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction, oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc, uaccess, zram, and cleanups). * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits) mm: cleanup kstrto*() usage mm: fix fall-through warnings for Clang mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at mm: shmem: convert shmem_enabled_show to use sysfs_emit_at mm:backing-dev: use sysfs_emit in macro defining functions mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening mm: use sysfs_emit for struct kobject * uses mm: fix kernel-doc markups zram: break the strict dependency from lzo zram: add stat to gather incompressible pages since zram set up zram: support page writeback mm/process_vm_access: remove redundant initialization of iov_r mm/zsmalloc.c: rework the list_add code in insert_zspage() mm/zswap: move to use crypto_acomp API for hardware acceleration mm/zswap: fix passing zero to 'PTR_ERR' warning mm/zswap: make struct kernel_param_ops definitions const userfaultfd/selftests: hint the test runner on required privilege userfaultfd/selftests: fix retval check for userfaultfd_open() userfaultfd/selftests: always dump something in modes userfaultfd: selftests: make __{s,u}64 format specifiers portable ...
Diffstat (limited to 'mm/highmem.c')
-rw-r--r--mm/highmem.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 83f9660f168f..c3a9ea7875ef 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -359,6 +359,58 @@ void kunmap_high(struct page *page)
wake_up(pkmap_map_wait);
}
EXPORT_SYMBOL(kunmap_high);
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2)
+{
+ unsigned int i;
+
+ BUG_ON(end1 > page_size(page) || end2 > page_size(page));
+
+ for (i = 0; i < compound_nr(page); i++) {
+ void *kaddr = NULL;
+
+ if (start1 < PAGE_SIZE || start2 < PAGE_SIZE)
+ kaddr = kmap_atomic(page + i);
+
+ if (start1 >= PAGE_SIZE) {
+ start1 -= PAGE_SIZE;
+ end1 -= PAGE_SIZE;
+ } else {
+ unsigned this_end = min_t(unsigned, end1, PAGE_SIZE);
+
+ if (end1 > start1)
+ memset(kaddr + start1, 0, this_end - start1);
+ end1 -= this_end;
+ start1 = 0;
+ }
+
+ if (start2 >= PAGE_SIZE) {
+ start2 -= PAGE_SIZE;
+ end2 -= PAGE_SIZE;
+ } else {
+ unsigned this_end = min_t(unsigned, end2, PAGE_SIZE);
+
+ if (end2 > start2)
+ memset(kaddr + start2, 0, this_end - start2);
+ end2 -= this_end;
+ start2 = 0;
+ }
+
+ if (kaddr) {
+ kunmap_atomic(kaddr);
+ flush_dcache_page(page + i);
+ }
+
+ if (!end1 && !end2)
+ break;
+ }
+
+ BUG_ON((start1 | start2 | end1 | end2) != 0);
+}
+EXPORT_SYMBOL(zero_user_segments);
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* CONFIG_HIGHMEM */
#ifdef CONFIG_KMAP_LOCAL