diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 21:32:19 +0100 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-03-21 21:32:19 +0100 |
commit | 3a990a52f9f25f45469e272017a31e7a3fda60ed (patch) | |
tree | 366f639d9ce1e907b65caa72bc098df6c4b5a240 /mm | |
parent | Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/... (diff) | |
parent | VM: make zap_page_range() callers that act on a single VMA use separate helper (diff) | |
download | linux-3a990a52f9f25f45469e272017a31e7a3fda60ed.tar.xz linux-3a990a52f9f25f45469e272017a31e7a3fda60ed.zip |
Merge branch 'vm' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull munmap/truncate race fixes from Al Viro:
"Fixes for racy use of unmap_vmas() on truncate-related codepaths"
* 'vm' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
VM: make zap_page_range() callers that act on a single VMA use separate helper
VM: make unmap_vmas() return void
VM: don't bother with feeding upper limit to tlb_finish_mmu() in exit_mmap()
VM: make zap_page_range() return void
VM: can't go through the inner loop in unmap_vmas() more than once...
VM: unmap_page_range() can return void
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memory.c | 133 | ||||
-rw-r--r-- | mm/mmap.c | 5 |
2 files changed, 82 insertions, 56 deletions
diff --git a/mm/memory.c b/mm/memory.c index 347e5fad1cfa..8438c157e4d9 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1282,10 +1282,10 @@ static inline unsigned long zap_pud_range(struct mmu_gather *tlb, return addr; } -static unsigned long unmap_page_range(struct mmu_gather *tlb, - struct vm_area_struct *vma, - unsigned long addr, unsigned long end, - struct zap_details *details) +static void unmap_page_range(struct mmu_gather *tlb, + struct vm_area_struct *vma, + unsigned long addr, unsigned long end, + struct zap_details *details) { pgd_t *pgd; unsigned long next; @@ -1305,8 +1305,47 @@ static unsigned long unmap_page_range(struct mmu_gather *tlb, } while (pgd++, addr = next, addr != end); tlb_end_vma(tlb, vma); mem_cgroup_uncharge_end(); +} - return addr; + +static void unmap_single_vma(struct mmu_gather *tlb, + struct vm_area_struct *vma, unsigned long start_addr, + unsigned long end_addr, unsigned long *nr_accounted, + struct zap_details *details) +{ + unsigned long start = max(vma->vm_start, start_addr); + unsigned long end; + + if (start >= vma->vm_end) + return; + end = min(vma->vm_end, end_addr); + if (end <= vma->vm_start) + return; + + if (vma->vm_flags & VM_ACCOUNT) + *nr_accounted += (end - start) >> PAGE_SHIFT; + + if (unlikely(is_pfn_mapping(vma))) + untrack_pfn_vma(vma, 0, 0); + + if (start != end) { + if (unlikely(is_vm_hugetlb_page(vma))) { + /* + * It is undesirable to test vma->vm_file as it + * should be non-null for valid hugetlb area. + * However, vm_file will be NULL in the error + * cleanup path of do_mmap_pgoff. When + * hugetlbfs ->mmap method fails, + * do_mmap_pgoff() nullifies vma->vm_file + * before calling this function to clean up. + * Since no pte has actually been setup, it is + * safe to do nothing in this case. + */ + if (vma->vm_file) + unmap_hugepage_range(vma, start, end, NULL); + } else + unmap_page_range(tlb, vma, start, end, details); + } } /** @@ -1318,8 +1357,6 @@ static unsigned long unmap_page_range(struct mmu_gather *tlb, * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here * @details: details of nonlinear truncation or shared cache invalidation * - * Returns the end address of the unmapping (restart addr if interrupted). - * * Unmap all pages in the vma list. * * Only addresses between `start' and `end' will be unmapped. @@ -1331,55 +1368,18 @@ static unsigned long unmap_page_range(struct mmu_gather *tlb, * ensure that any thus-far unmapped pages are flushed before unmap_vmas() * drops the lock and schedules. */ -unsigned long unmap_vmas(struct mmu_gather *tlb, +void unmap_vmas(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start_addr, unsigned long end_addr, unsigned long *nr_accounted, struct zap_details *details) { - unsigned long start = start_addr; struct mm_struct *mm = vma->vm_mm; mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); - for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { - unsigned long end; - - start = max(vma->vm_start, start_addr); - if (start >= vma->vm_end) - continue; - end = min(vma->vm_end, end_addr); - if (end <= vma->vm_start) - continue; - - if (vma->vm_flags & VM_ACCOUNT) - *nr_accounted += (end - start) >> PAGE_SHIFT; - - if (unlikely(is_pfn_mapping(vma))) - untrack_pfn_vma(vma, 0, 0); - - while (start != end) { - if (unlikely(is_vm_hugetlb_page(vma))) { - /* - * It is undesirable to test vma->vm_file as it - * should be non-null for valid hugetlb area. - * However, vm_file will be NULL in the error - * cleanup path of do_mmap_pgoff. When - * hugetlbfs ->mmap method fails, - * do_mmap_pgoff() nullifies vma->vm_file - * before calling this function to clean up. - * Since no pte has actually been setup, it is - * safe to do nothing in this case. - */ - if (vma->vm_file) - unmap_hugepage_range(vma, start, end, NULL); - - start = end; - } else - start = unmap_page_range(tlb, vma, start, end, details); - } - } - + for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) + unmap_single_vma(tlb, vma, start_addr, end_addr, nr_accounted, + details); mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); - return start; /* which is now the end (or restart) address */ } /** @@ -1388,8 +1388,34 @@ unsigned long unmap_vmas(struct mmu_gather *tlb, * @address: starting address of pages to zap * @size: number of bytes to zap * @details: details of nonlinear truncation or shared cache invalidation + * + * Caller must protect the VMA list + */ +void zap_page_range(struct vm_area_struct *vma, unsigned long address, + unsigned long size, struct zap_details *details) +{ + struct mm_struct *mm = vma->vm_mm; + struct mmu_gather tlb; + unsigned long end = address + size; + unsigned long nr_accounted = 0; + + lru_add_drain(); + tlb_gather_mmu(&tlb, mm, 0); + update_hiwater_rss(mm); + unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); + tlb_finish_mmu(&tlb, address, end); +} + +/** + * zap_page_range_single - remove user pages in a given range + * @vma: vm_area_struct holding the applicable pages + * @address: starting address of pages to zap + * @size: number of bytes to zap + * @details: details of nonlinear truncation or shared cache invalidation + * + * The range must fit into one VMA. */ -unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, +static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, unsigned long size, struct zap_details *details) { struct mm_struct *mm = vma->vm_mm; @@ -1400,9 +1426,10 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, lru_add_drain(); tlb_gather_mmu(&tlb, mm, 0); update_hiwater_rss(mm); - end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); + mmu_notifier_invalidate_range_start(mm, address, end); + unmap_single_vma(&tlb, vma, address, end, &nr_accounted, details); + mmu_notifier_invalidate_range_end(mm, address, end); tlb_finish_mmu(&tlb, address, end); - return end; } /** @@ -1423,7 +1450,7 @@ int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, if (address < vma->vm_start || address + size > vma->vm_end || !(vma->vm_flags & VM_PFNMAP)) return -1; - zap_page_range(vma, address, size, NULL); + zap_page_range_single(vma, address, size, NULL); return 0; } EXPORT_SYMBOL_GPL(zap_vma_ptes); @@ -2770,7 +2797,7 @@ static void unmap_mapping_range_vma(struct vm_area_struct *vma, unsigned long start_addr, unsigned long end_addr, struct zap_details *details) { - zap_page_range(vma, start_addr, end_addr - start_addr, details); + zap_page_range_single(vma, start_addr, end_addr - start_addr, details); } static inline void unmap_mapping_range_tree(struct prio_tree_root *root, diff --git a/mm/mmap.c b/mm/mmap.c index 39a68ddf38bd..6f3766b57803 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2237,7 +2237,6 @@ void exit_mmap(struct mm_struct *mm) struct mmu_gather tlb; struct vm_area_struct *vma; unsigned long nr_accounted = 0; - unsigned long end; /* mm's last user has gone, and its about to be pulled down */ mmu_notifier_release(mm); @@ -2262,11 +2261,11 @@ void exit_mmap(struct mm_struct *mm) tlb_gather_mmu(&tlb, mm, 1); /* update_hiwater_rss(mm) here? but nobody should be looking */ /* Use -1 here to ensure all VMAs in the mm are unmapped */ - end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); + unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); - tlb_finish_mmu(&tlb, 0, end); + tlb_finish_mmu(&tlb, 0, -1); /* * Walk the list again, actually closing and freeing it, |