diff options
| author | Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2015-09-09 00:59:42 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-09-09 01:35:28 +0300 |
| commit | 46c043ede4711e8d598b9d63c5616c1fedb0605e (patch) | |
| tree | 8a559930980f59ef24c25b73b91899106f8f0418 /fs | |
| parent | 3fdd1b479dbc03347e98f904f54133a9cef5521f (diff) | |
| download | linux-46c043ede4711e8d598b9d63c5616c1fedb0605e.tar.xz | |
mm: take i_mmap_lock in unmap_mapping_range() for DAX
DAX is not so special: we need i_mmap_lock to protect mapping->i_mmap.
__dax_pmd_fault() uses unmap_mapping_range() shoot out zero page from
all mappings. We need to drop i_mmap_lock there to avoid lock deadlock.
Re-aquiring the lock should be fine since we check i_size after the
point.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/dax.c | 35 |
1 files changed, 19 insertions, 16 deletions
@@ -554,6 +554,25 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) goto fallback; + if (buffer_unwritten(&bh) || buffer_new(&bh)) { + int i; + for (i = 0; i < PTRS_PER_PMD; i++) + clear_page(kaddr + i * PAGE_SIZE); + count_vm_event(PGMAJFAULT); + mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); + result |= VM_FAULT_MAJOR; + } + + /* + * If we allocated new storage, make sure no process has any + * zero pages covering this hole + */ + if (buffer_new(&bh)) { + i_mmap_unlock_write(mapping); + unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0); + i_mmap_lock_write(mapping); + } + /* * If a truncate happened while we were allocating blocks, we may * leave blocks allocated to the file that are beyond EOF. We can't @@ -568,13 +587,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if ((pgoff | PG_PMD_COLOUR) >= size) goto fallback; - /* - * If we allocated new storage, make sure no process has any - * zero pages covering this hole - */ - if (buffer_new(&bh)) - unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0); - if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) { spinlock_t *ptl; pmd_t entry; @@ -605,15 +617,6 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR)) goto fallback; - if (buffer_unwritten(&bh) || buffer_new(&bh)) { - int i; - for (i = 0; i < PTRS_PER_PMD; i++) - clear_page(kaddr + i * PAGE_SIZE); - count_vm_event(PGMAJFAULT); - mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); - result |= VM_FAULT_MAJOR; - } - result |= vmf_insert_pfn_pmd(vma, address, pmd, pfn, write); } |