diff options
| -rw-r--r-- | mm/mremap.c | 120 |
1 files changed, 72 insertions, 48 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 67761361c469..5f346178f16f 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -313,6 +313,59 @@ Eagain: return ERR_PTR(-EAGAIN); } +static unsigned long mremap_to(unsigned long addr, + unsigned long old_len, unsigned long new_addr, + unsigned long new_len) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long ret = -EINVAL; + unsigned long charged = 0; + + if (new_addr & ~PAGE_MASK) + goto out; + + if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len) + goto out; + + /* Check if the location we're moving into overlaps the + * old location at all, and fail if it does. + */ + if ((new_addr <= addr) && (new_addr+new_len) > addr) + goto out; + + if ((addr <= new_addr) && (addr+old_len) > new_addr) + goto out; + + ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1); + if (ret) + goto out; + + ret = do_munmap(mm, new_addr, new_len); + if (ret) + goto out; + + if (old_len >= new_len) { + ret = do_munmap(mm, addr+new_len, old_len - new_len); + if (ret && old_len != new_len) + goto out; + old_len = new_len; + } + + vma = vma_to_resize(addr, old_len, new_len, &charged); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto out; + } + + ret = move_vma(vma, addr, old_len, new_len, new_addr); + if (ret & ~PAGE_MASK) + vm_unacct_memory(charged); + +out: + return ret; +} + /* * Expand (or shrink) an existing mapping, potentially moving it at the * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) @@ -346,32 +399,10 @@ unsigned long do_mremap(unsigned long addr, if (!new_len) goto out; - /* new_addr is only valid if MREMAP_FIXED is specified */ if (flags & MREMAP_FIXED) { - if (new_addr & ~PAGE_MASK) - goto out; - if (!(flags & MREMAP_MAYMOVE)) - goto out; - - if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len) - goto out; - - /* Check if the location we're moving into overlaps the - * old location at all, and fail if it does. - */ - if ((new_addr <= addr) && (new_addr+new_len) > addr) - goto out; - - if ((addr <= new_addr) && (addr+old_len) > new_addr) - goto out; - - ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1); - if (ret) - goto out; - - ret = do_munmap(mm, new_addr, new_len); - if (ret) - goto out; + if (flags & MREMAP_MAYMOVE) + ret = mremap_to(addr, old_len, new_addr, new_len); + goto out; } /* @@ -384,13 +415,11 @@ unsigned long do_mremap(unsigned long addr, if (ret && old_len != new_len) goto out; ret = addr; - if (!(flags & MREMAP_FIXED) || (new_addr == addr)) - goto out; - old_len = new_len; + goto out; } /* - * Ok, we need to grow.. or relocate. + * Ok, we need to grow.. */ vma = vma_to_resize(addr, old_len, new_len, &charged); if (IS_ERR(vma)) { @@ -399,11 +428,8 @@ unsigned long do_mremap(unsigned long addr, } /* old_len exactly to the end of the area.. - * And we're not relocating the area. */ - if (old_len == vma->vm_end - addr && - !((flags & MREMAP_FIXED) && (addr != new_addr)) && - (old_len != new_len || !(flags & MREMAP_MAYMOVE))) { + if (old_len == vma->vm_end - addr) { unsigned long max_addr = TASK_SIZE; if (vma->vm_next) max_addr = vma->vm_next->vm_start; @@ -432,22 +458,20 @@ unsigned long do_mremap(unsigned long addr, */ ret = -ENOMEM; if (flags & MREMAP_MAYMOVE) { - if (!(flags & MREMAP_FIXED)) { - unsigned long map_flags = 0; - if (vma->vm_flags & VM_MAYSHARE) - map_flags |= MAP_SHARED; - - new_addr = get_unmapped_area(vma->vm_file, 0, new_len, - vma->vm_pgoff, map_flags); - if (new_addr & ~PAGE_MASK) { - ret = new_addr; - goto out; - } - - ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1); - if (ret) - goto out; + unsigned long map_flags = 0; + if (vma->vm_flags & VM_MAYSHARE) + map_flags |= MAP_SHARED; + + new_addr = get_unmapped_area(vma->vm_file, 0, new_len, + vma->vm_pgoff, map_flags); + if (new_addr & ~PAGE_MASK) { + ret = new_addr; + goto out; } + + ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1); + if (ret) + goto out; ret = move_vma(vma, addr, old_len, new_len, new_addr); } out: |