diff options
| author | Mike Kravetz <mike.kravetz@oracle.com> | 2017-02-22 15:43:10 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-22 16:41:28 -0800 |
| commit | 369cd2121be440543280b91056de187f625d0dbb (patch) | |
| tree | 800cc640df4ee6e627f61e277d27b3d90936e0a5 | |
| parent | 9903bd7b73ef0dec429e951009b36643eb0fe239 (diff) | |
userfaultfd: hugetlbfs: userfaultfd_huge_must_wait for hugepmd ranges
Add routine userfaultfd_huge_must_wait which has the same functionality
as the existing userfaultfd_must_wait routine. Only difference is that
new routine must handle page table structure for hugepmd vmas.
Link: http://lkml.kernel.org/r/20161216144821.5183-24-aarcange@redhat.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/userfaultfd.c | 51 |
1 files changed, 49 insertions, 2 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 5139d05f80e6..11b5e65e8fba 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -202,6 +202,49 @@ static inline struct uffd_msg userfault_msg(unsigned long address, return msg; } +#ifdef CONFIG_HUGETLB_PAGE +/* + * Same functionality as userfaultfd_must_wait below with modifications for + * hugepmd ranges. + */ +static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx, + unsigned long address, + unsigned long flags, + unsigned long reason) +{ + struct mm_struct *mm = ctx->mm; + pte_t *pte; + bool ret = true; + + VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); + + pte = huge_pte_offset(mm, address); + if (!pte) + goto out; + + ret = false; + + /* + * Lockless access: we're in a wait_event so it's ok if it + * changes under us. + */ + if (huge_pte_none(*pte)) + ret = true; + if (!huge_pte_write(*pte) && (reason & VM_UFFD_WP)) + ret = true; +out: + return ret; +} +#else +static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx, + unsigned long address, + unsigned long flags, + unsigned long reason) +{ + return false; /* should never get here */ +} +#endif /* CONFIG_HUGETLB_PAGE */ + /* * Verify the pagetables are still not ok after having reigstered into * the fault_pending_wqh to avoid userland having to UFFDIO_WAKE any @@ -378,8 +421,12 @@ int handle_userfault(struct vm_fault *vmf, unsigned long reason) set_current_state(blocking_state); spin_unlock(&ctx->fault_pending_wqh.lock); - must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags, - reason); + if (!is_vm_hugetlb_page(vmf->vma)) + must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags, + reason); + else + must_wait = userfaultfd_huge_must_wait(ctx, vmf->address, + vmf->flags, reason); up_read(&mm->mmap_sem); if (likely(must_wait && !ACCESS_ONCE(ctx->released) && |