diff options
Diffstat (limited to 'mm/mlock.c')
| -rw-r--r-- | mm/mlock.c | 100 |
1 files changed, 68 insertions, 32 deletions
diff --git a/mm/mlock.c b/mm/mlock.c index 25936680064f..339d9e0949b6 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -422,7 +422,7 @@ static unsigned long __munlock_pagevec_fill(struct pagevec *pvec, void munlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { - vma->vm_flags &= ~VM_LOCKED; + vma->vm_flags &= VM_LOCKED_CLEAR_MASK; while (start < end) { struct page *page = NULL; @@ -506,7 +506,8 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm)) - goto out; /* don't set VM_LOCKED, don't count */ + /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ + goto out; pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT); *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma, @@ -554,13 +555,14 @@ out: return ret; } -static int do_mlock(unsigned long start, size_t len, int on) +static int apply_vma_lock_flags(unsigned long start, size_t len, + vm_flags_t flags) { unsigned long nstart, end, tmp; struct vm_area_struct * vma, * prev; int error; - VM_BUG_ON(start & ~PAGE_MASK); + VM_BUG_ON(offset_in_page(start)); VM_BUG_ON(len != PAGE_ALIGN(len)); end = start + len; if (end < start) @@ -576,14 +578,11 @@ static int do_mlock(unsigned long start, size_t len, int on) prev = vma; for (nstart = start ; ; ) { - vm_flags_t newflags; + vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; - /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ - - newflags = vma->vm_flags & ~VM_LOCKED; - if (on) - newflags |= VM_LOCKED; + newflags |= flags; + /* Here we know that vma->vm_start <= nstart < vma->vm_end. */ tmp = vma->vm_end; if (tmp > end) tmp = end; @@ -605,7 +604,7 @@ static int do_mlock(unsigned long start, size_t len, int on) return error; } -SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) +static int do_mlock(unsigned long start, size_t len, vm_flags_t flags) { unsigned long locked; unsigned long lock_limit; @@ -616,7 +615,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) lru_add_drain_all(); /* flush pagevec */ - len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); + len = PAGE_ALIGN(len + (offset_in_page(start))); start &= PAGE_MASK; lock_limit = rlimit(RLIMIT_MEMLOCK); @@ -629,7 +628,7 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) /* check against resource limits */ if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) - error = do_mlock(start, len, 1); + error = apply_vma_lock_flags(start, len, flags); up_write(¤t->mm->mmap_sem); if (error) @@ -641,37 +640,75 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) return 0; } +SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) +{ + return do_mlock(start, len, VM_LOCKED); +} + +SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags) +{ + vm_flags_t vm_flags = VM_LOCKED; + + if (flags & ~MLOCK_ONFAULT) + return -EINVAL; + + if (flags & MLOCK_ONFAULT) + vm_flags |= VM_LOCKONFAULT; + + return do_mlock(start, len, vm_flags); +} + SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) { int ret; - len = PAGE_ALIGN(len + (start & ~PAGE_MASK)); + len = PAGE_ALIGN(len + (offset_in_page(start))); start &= PAGE_MASK; down_write(¤t->mm->mmap_sem); - ret = do_mlock(start, len, 0); + ret = apply_vma_lock_flags(start, len, 0); up_write(¤t->mm->mmap_sem); return ret; } -static int do_mlockall(int flags) +/* + * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall) + * and translate into the appropriate modifications to mm->def_flags and/or the + * flags for all current VMAs. + * + * There are a couple of subtleties with this. If mlockall() is called multiple + * times with different flags, the values do not necessarily stack. If mlockall + * is called once including the MCL_FUTURE flag and then a second time without + * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags. + */ +static int apply_mlockall_flags(int flags) { struct vm_area_struct * vma, * prev = NULL; + vm_flags_t to_add = 0; - if (flags & MCL_FUTURE) + current->mm->def_flags &= VM_LOCKED_CLEAR_MASK; + if (flags & MCL_FUTURE) { current->mm->def_flags |= VM_LOCKED; - else - current->mm->def_flags &= ~VM_LOCKED; - if (flags == MCL_FUTURE) - goto out; + + if (flags & MCL_ONFAULT) + current->mm->def_flags |= VM_LOCKONFAULT; + + if (!(flags & MCL_CURRENT)) + goto out; + } + + if (flags & MCL_CURRENT) { + to_add |= VM_LOCKED; + if (flags & MCL_ONFAULT) + to_add |= VM_LOCKONFAULT; + } 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_CLEAR_MASK; + newflags |= to_add; /* Ignore errors */ mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags); @@ -684,14 +721,13 @@ out: SYSCALL_DEFINE1(mlockall, int, flags) { unsigned long lock_limit; - int ret = -EINVAL; + int ret; - if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE))) - goto out; + if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT))) + return -EINVAL; - ret = -EPERM; if (!can_do_mlock()) - goto out; + return -EPERM; if (flags & MCL_CURRENT) lru_add_drain_all(); /* flush pagevec */ @@ -704,11 +740,11 @@ SYSCALL_DEFINE1(mlockall, int, flags) if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) || capable(CAP_IPC_LOCK)) - ret = do_mlockall(flags); + ret = apply_mlockall_flags(flags); up_write(¤t->mm->mmap_sem); if (!ret && (flags & MCL_CURRENT)) mm_populate(0, TASK_SIZE); -out: + return ret; } @@ -717,7 +753,7 @@ SYSCALL_DEFINE0(munlockall) int ret; down_write(¤t->mm->mmap_sem); - ret = do_mlockall(0); + ret = apply_mlockall_flags(0); up_write(¤t->mm->mmap_sem); return ret; } |