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Commit ce53e8e6 authored by Mike Rapoport's avatar Mike Rapoport Committed by Linus Torvalds
Browse files

userfaultfd: report UFFDIO_ZEROPAGE as available for shmem VMAs 

Now when shmem VMAs can be filled with zero page via userfaultfd we can
report that UFFDIO_ZEROPAGE is available for those VMAs

Link: http://lkml.kernel.org/r/1497939652-16528-7-git-send-email-rppt@linux.vnet.ibm.com


Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8fb44e54

fs/userfaultfd.c

+5 −5
Original line number Diff line number Diff line
@@ -1194,7 +1194,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
	struct uffdio_register __user *user_uffdio_register;

	unsigned long vm_flags, new_flags;

	bool found;

	bool non_anon_pages;

	bool basic_ioctls;

	unsigned long start, end, vma_end;



	user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1260,7 +1260,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
	 * Search for not compatible vmas.

	 */

	found = false;

	non_anon_pages = false;

	basic_ioctls = false;

	for (cur = vma; cur && cur->vm_start < end; cur = cur->vm_next) {

		cond_resched();
@@ -1299,8 +1299,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
		/*

		 * Note vmas containing huge pages

		 */

		if (is_vm_hugetlb_page(cur) || vma_is_shmem(cur))

			non_anon_pages = true;

		if (is_vm_hugetlb_page(cur))

			basic_ioctls = true;



		found = true;

	}
@@ -1371,7 +1371,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
		 * userland which ioctls methods are guaranteed to

		 * succeed on this range.

		 */

		if (put_user(non_anon_pages ? UFFD_API_RANGE_IOCTLS_BASIC :

		if (put_user(basic_ioctls ? UFFD_API_RANGE_IOCTLS_BASIC :

			     UFFD_API_RANGE_IOCTLS,

			     &user_uffdio_register->ioctls))

			ret = -EFAULT;