diff options
Diffstat (limited to 'mm/mlock.c')
| -rw-r--r-- | mm/mlock.c | 103 |
1 files changed, 31 insertions, 72 deletions
diff --git a/mm/mlock.c b/mm/mlock.c index f0b9ce572fc..e6638f565d4 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -155,13 +155,12 @@ void munlock_vma_page(struct page *page) * * vma->vm_mm->mmap_sem must be held for at least read. */ -static long __mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end, - int *nonblocking) +long __mlock_vma_pages_range(struct vm_area_struct *vma, + unsigned long start, unsigned long end, int *nonblocking) { struct mm_struct *mm = vma->vm_mm; unsigned long addr = start; - int nr_pages = (end - start) / PAGE_SIZE; + unsigned long nr_pages = (end - start) / PAGE_SIZE; int gup_flags; VM_BUG_ON(start & ~PAGE_MASK); @@ -186,6 +185,10 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma, if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) gup_flags |= FOLL_FORCE; + /* + * We made sure addr is within a VMA, so the following will + * not result in a stack expansion that recurses back here. + */ return __get_user_pages(current, mm, addr, nr_pages, gup_flags, NULL, NULL, nonblocking); } @@ -202,56 +205,6 @@ static int __mlock_posix_error_return(long retval) return retval; } -/** - * mlock_vma_pages_range() - mlock pages in specified vma range. - * @vma - the vma containing the specfied address range - * @start - starting address in @vma to mlock - * @end - end address [+1] in @vma to mlock - * - * For mmap()/mremap()/expansion of mlocked vma. - * - * return 0 on success for "normal" vmas. - * - * return number of pages [> 0] to be removed from locked_vm on success - * of "special" vmas. - */ -long mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end) -{ - int nr_pages = (end - start) / PAGE_SIZE; - BUG_ON(!(vma->vm_flags & VM_LOCKED)); - - /* - * filter unlockable vmas - */ - if (vma->vm_flags & (VM_IO | VM_PFNMAP)) - goto no_mlock; - - if (!((vma->vm_flags & VM_DONTEXPAND) || - is_vm_hugetlb_page(vma) || - vma == get_gate_vma(current->mm))) { - - __mlock_vma_pages_range(vma, start, end, NULL); - - /* Hide errors from mmap() and other callers */ - return 0; - } - - /* - * User mapped kernel pages or huge pages: - * make these pages present to populate the ptes, but - * fall thru' to reset VM_LOCKED--no need to unlock, and - * return nr_pages so these don't get counted against task's - * locked limit. huge pages are already counted against - * locked vm limit. - */ - make_pages_present(start, end); - -no_mlock: - vma->vm_flags &= ~VM_LOCKED; /* and don't come back! */ - return nr_pages; /* error or pages NOT mlocked */ -} - /* * munlock_vma_pages_range() - munlock all pages in the vma range.' * @vma - vma containing range to be munlock()ed. @@ -303,7 +256,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma, * * Filters out "special" vmas -- VM_LOCKED never gets set for these, and * munlock is a no-op. However, for some special vmas, we go ahead and - * populate the ptes via make_pages_present(). + * populate the ptes. * * For vmas that pass the filters, merge/split as appropriate. */ @@ -391,9 +344,9 @@ static int do_mlock(unsigned long start, size_t len, int on) /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ - newflags = vma->vm_flags | VM_LOCKED; - if (!on) - newflags &= ~VM_LOCKED; + newflags = vma->vm_flags & ~VM_LOCKED; + if (on) + newflags |= VM_LOCKED | VM_POPULATE; tmp = vma->vm_end; if (tmp > end) @@ -416,13 +369,20 @@ static int do_mlock(unsigned long start, size_t len, int on) return error; } -static int do_mlock_pages(unsigned long start, size_t len, int ignore_errors) +/* + * __mm_populate - populate and/or mlock pages within a range of address space. + * + * This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap + * flags. VMAs must be already marked with the desired vm_flags, and + * mmap_sem must not be held. + */ +int __mm_populate(unsigned long start, unsigned long len, int ignore_errors) { struct mm_struct *mm = current->mm; unsigned long end, nstart, nend; struct vm_area_struct *vma = NULL; int locked = 0; - int ret = 0; + long ret = 0; VM_BUG_ON(start & ~PAGE_MASK); VM_BUG_ON(len != PAGE_ALIGN(len)); @@ -446,7 +406,8 @@ static int do_mlock_pages(unsigned long start, size_t len, int ignore_errors) * range with the first VMA. Also, skip undesirable VMA types. */ nend = min(end, vma->vm_end); - if (vma->vm_flags & (VM_IO | VM_PFNMAP)) + if ((vma->vm_flags & (VM_IO | VM_PFNMAP | VM_POPULATE)) != + VM_POPULATE) continue; if (nstart < vma->vm_start) nstart = vma->vm_start; @@ -498,7 +459,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) error = do_mlock(start, len, 1); up_write(¤t->mm->mmap_sem); if (!error) - error = do_mlock_pages(start, len, 0); + error = __mm_populate(start, len, 0); return error; } @@ -517,20 +478,20 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) static int do_mlockall(int flags) { struct vm_area_struct * vma, * prev = NULL; - unsigned int def_flags = 0; if (flags & MCL_FUTURE) - def_flags = VM_LOCKED; - current->mm->def_flags = def_flags; + current->mm->def_flags |= VM_LOCKED | VM_POPULATE; + else + current->mm->def_flags &= ~(VM_LOCKED | VM_POPULATE); if (flags == MCL_FUTURE) goto out; for (vma = current->mm->mmap; vma ; vma = prev->vm_next) { vm_flags_t newflags; - newflags = vma->vm_flags | VM_LOCKED; - if (!(flags & MCL_CURRENT)) - newflags &= ~VM_LOCKED; + newflags = vma->vm_flags & ~VM_LOCKED; + if (flags & MCL_CURRENT) + newflags |= VM_LOCKED | VM_POPULATE; /* Ignore errors */ mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); @@ -564,10 +525,8 @@ SYSCALL_DEFINE1(mlockall, int, flags) capable(CAP_IPC_LOCK)) ret = do_mlockall(flags); up_write(¤t->mm->mmap_sem); - if (!ret && (flags & MCL_CURRENT)) { - /* Ignore errors */ - do_mlock_pages(0, TASK_SIZE, 1); - } + if (!ret && (flags & MCL_CURRENT)) + mm_populate(0, TASK_SIZE); out: return ret; } |