mmap: allow MAP_HUGETLB for hugetlbfs files v2 (493af578) · Commits · 戴 / test

It is counterintuitive at best that mmap'ing a hugetlbfs file with MAP_HUGETLB fails, while mmap'ing it without will a) succeed and b) return huge pages. v2: use is_file_hugepages(), as suggested by Jianguo Signed-off-by:

Joern Engel <joern@logfs.org> Cc: Jianguo Wu <wujianguo@huawei.com> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/mmap.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -1358,13 +1358,14 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,

		if (!(flags & MAP_ANONYMOUS)) {
		audit_mmap_fd(fd, flags);
		if (unlikely(flags & MAP_HUGETLB))
		return -EINVAL;
		file = fget(fd);
		if (!file)
		goto out;
		if (is_file_hugepages(file))
		len = ALIGN(len, huge_page_size(hstate_file(file)));
		retval = -EINVAL;
		if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
		goto out_fput;
		} else if (flags & MAP_HUGETLB) {
		struct user_struct *user = NULL;
		struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) &
		@@ -1391,6 +1392,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
		flags &= ~(MAP_EXECUTABLE \| MAP_DENYWRITE);

		retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
		out_fput:
		if (file)
		fput(file);
		out:

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