From 42fc541404f249778e752ab39c8bc25fcb2dbe1e Mon Sep 17 00:00:00 2001 From: Michel Lespinasse Date: Mon, 8 Jun 2020 21:33:44 -0700 Subject: mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked() Add new APIs to assert that mmap_sem is held. Using this instead of rwsem_is_locked and lockdep_assert_held[_write] makes the assertions more tolerant of future changes to the lock type. Signed-off-by: Michel Lespinasse Signed-off-by: Andrew Morton Reviewed-by: Vlastimil Babka Reviewed-by: Daniel Jordan Cc: Davidlohr Bueso Cc: David Rientjes Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Laurent Dufour Cc: Liam Howlett Cc: Matthew Wilcox Cc: Peter Zijlstra Cc: Ying Han Link: http://lkml.kernel.org/r/20200520052908.204642-10-walken@google.com Signed-off-by: Linus Torvalds --- fs/userfaultfd.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 9c645eee1a59..12b492409040 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -234,7 +234,7 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx, pte_t *ptep, pte; bool ret = true; - VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); + mmap_assert_locked(mm); ptep = huge_pte_offset(mm, address, vma_mmu_pagesize(vma)); @@ -286,7 +286,7 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, pte_t *pte; bool ret = true; - VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem)); + mmap_assert_locked(mm); pgd = pgd_offset(mm, address); if (!pgd_present(*pgd)) @@ -405,7 +405,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) * Coredumping runs without mmap_sem so we can only check that * the mmap_sem is held, if PF_DUMPCORE was not set. */ - WARN_ON_ONCE(!rwsem_is_locked(&mm->mmap_sem)); + mmap_assert_locked(mm); ctx = vmf->vma->vm_userfaultfd_ctx.ctx; if (!ctx) -- cgit v1.2.3