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SubjectRe: [PATCH] mmap: allow MAP_HUGETLB for hugetlbfs files v2
Hi Joern,

I cannot apply this patch to Linus tree, as the code has been modified since
commit af73e4d9506d ("hugetlbfs: fix mmap failure in unaligned size request").

Thanks,
Jianguo Wu

On 2013/6/20 0:25, Jörn Engel wrote:

> 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>
> ---
> mm/mmap.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 2a594246..cdc8e7a 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1322,11 +1322,12 @@ 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;
> + retval = -EINVAL;
> + if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
> + goto out_fput;
> } else if (flags & MAP_HUGETLB) {
> struct user_struct *user = NULL;
> /*
> @@ -1346,6 +1347,7 @@ 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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