11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * mm/mremap.c 31da177e4SLinus Torvalds * 41da177e4SLinus Torvalds * (C) Copyright 1996 Linus Torvalds 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Address space accounting code <alan@redhat.com> 71da177e4SLinus Torvalds * (C) Copyright 2002 Red Hat Inc, All Rights Reserved 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 101da177e4SLinus Torvalds #include <linux/mm.h> 111da177e4SLinus Torvalds #include <linux/hugetlb.h> 121da177e4SLinus Torvalds #include <linux/slab.h> 131da177e4SLinus Torvalds #include <linux/shm.h> 141da177e4SLinus Torvalds #include <linux/mman.h> 151da177e4SLinus Torvalds #include <linux/swap.h> 161da177e4SLinus Torvalds #include <linux/fs.h> 171da177e4SLinus Torvalds #include <linux/highmem.h> 181da177e4SLinus Torvalds #include <linux/security.h> 191da177e4SLinus Torvalds #include <linux/syscalls.h> 201da177e4SLinus Torvalds 211da177e4SLinus Torvalds #include <asm/uaccess.h> 221da177e4SLinus Torvalds #include <asm/cacheflush.h> 231da177e4SLinus Torvalds #include <asm/tlbflush.h> 241da177e4SLinus Torvalds 251da177e4SLinus Torvalds static pte_t *get_one_pte_map_nested(struct mm_struct *mm, unsigned long addr) 261da177e4SLinus Torvalds { 271da177e4SLinus Torvalds pgd_t *pgd; 281da177e4SLinus Torvalds pud_t *pud; 291da177e4SLinus Torvalds pmd_t *pmd; 301da177e4SLinus Torvalds pte_t *pte = NULL; 311da177e4SLinus Torvalds 321da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 331da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 341da177e4SLinus Torvalds goto end; 351da177e4SLinus Torvalds 361da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 371da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 381da177e4SLinus Torvalds goto end; 391da177e4SLinus Torvalds 401da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 411da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 421da177e4SLinus Torvalds goto end; 431da177e4SLinus Torvalds 441da177e4SLinus Torvalds pte = pte_offset_map_nested(pmd, addr); 451da177e4SLinus Torvalds if (pte_none(*pte)) { 461da177e4SLinus Torvalds pte_unmap_nested(pte); 471da177e4SLinus Torvalds pte = NULL; 481da177e4SLinus Torvalds } 491da177e4SLinus Torvalds end: 501da177e4SLinus Torvalds return pte; 511da177e4SLinus Torvalds } 521da177e4SLinus Torvalds 531da177e4SLinus Torvalds static pte_t *get_one_pte_map(struct mm_struct *mm, unsigned long addr) 541da177e4SLinus Torvalds { 551da177e4SLinus Torvalds pgd_t *pgd; 561da177e4SLinus Torvalds pud_t *pud; 571da177e4SLinus Torvalds pmd_t *pmd; 581da177e4SLinus Torvalds 591da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 601da177e4SLinus Torvalds if (pgd_none_or_clear_bad(pgd)) 611da177e4SLinus Torvalds return NULL; 621da177e4SLinus Torvalds 631da177e4SLinus Torvalds pud = pud_offset(pgd, addr); 641da177e4SLinus Torvalds if (pud_none_or_clear_bad(pud)) 651da177e4SLinus Torvalds return NULL; 661da177e4SLinus Torvalds 671da177e4SLinus Torvalds pmd = pmd_offset(pud, addr); 681da177e4SLinus Torvalds if (pmd_none_or_clear_bad(pmd)) 691da177e4SLinus Torvalds return NULL; 701da177e4SLinus Torvalds 711da177e4SLinus Torvalds return pte_offset_map(pmd, addr); 721da177e4SLinus Torvalds } 731da177e4SLinus Torvalds 741da177e4SLinus Torvalds static inline pte_t *alloc_one_pte_map(struct mm_struct *mm, unsigned long addr) 751da177e4SLinus Torvalds { 761da177e4SLinus Torvalds pgd_t *pgd; 771da177e4SLinus Torvalds pud_t *pud; 781da177e4SLinus Torvalds pmd_t *pmd; 791da177e4SLinus Torvalds pte_t *pte = NULL; 801da177e4SLinus Torvalds 811da177e4SLinus Torvalds pgd = pgd_offset(mm, addr); 821da177e4SLinus Torvalds 831da177e4SLinus Torvalds pud = pud_alloc(mm, pgd, addr); 841da177e4SLinus Torvalds if (!pud) 851da177e4SLinus Torvalds return NULL; 861da177e4SLinus Torvalds pmd = pmd_alloc(mm, pud, addr); 871da177e4SLinus Torvalds if (pmd) 881da177e4SLinus Torvalds pte = pte_alloc_map(mm, pmd, addr); 891da177e4SLinus Torvalds return pte; 901da177e4SLinus Torvalds } 911da177e4SLinus Torvalds 921da177e4SLinus Torvalds static int 931da177e4SLinus Torvalds move_one_page(struct vm_area_struct *vma, unsigned long old_addr, 941da177e4SLinus Torvalds struct vm_area_struct *new_vma, unsigned long new_addr) 951da177e4SLinus Torvalds { 961da177e4SLinus Torvalds struct address_space *mapping = NULL; 971da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 981da177e4SLinus Torvalds int error = 0; 991da177e4SLinus Torvalds pte_t *src, *dst; 1001da177e4SLinus Torvalds 1011da177e4SLinus Torvalds if (vma->vm_file) { 1021da177e4SLinus Torvalds /* 1031da177e4SLinus Torvalds * Subtle point from Rajesh Venkatasubramanian: before 1041da177e4SLinus Torvalds * moving file-based ptes, we must lock vmtruncate out, 1051da177e4SLinus Torvalds * since it might clean the dst vma before the src vma, 1061da177e4SLinus Torvalds * and we propagate stale pages into the dst afterward. 1071da177e4SLinus Torvalds */ 1081da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 1091da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 1101da177e4SLinus Torvalds if (new_vma->vm_truncate_count && 1111da177e4SLinus Torvalds new_vma->vm_truncate_count != vma->vm_truncate_count) 1121da177e4SLinus Torvalds new_vma->vm_truncate_count = 0; 1131da177e4SLinus Torvalds } 1141da177e4SLinus Torvalds spin_lock(&mm->page_table_lock); 1151da177e4SLinus Torvalds 1161da177e4SLinus Torvalds src = get_one_pte_map_nested(mm, old_addr); 1171da177e4SLinus Torvalds if (src) { 1181da177e4SLinus Torvalds /* 1191da177e4SLinus Torvalds * Look to see whether alloc_one_pte_map needs to perform a 1201da177e4SLinus Torvalds * memory allocation. If it does then we need to drop the 1211da177e4SLinus Torvalds * atomic kmap 1221da177e4SLinus Torvalds */ 1231da177e4SLinus Torvalds dst = get_one_pte_map(mm, new_addr); 1241da177e4SLinus Torvalds if (unlikely(!dst)) { 1251da177e4SLinus Torvalds pte_unmap_nested(src); 1261da177e4SLinus Torvalds if (mapping) 1271da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 1281da177e4SLinus Torvalds dst = alloc_one_pte_map(mm, new_addr); 1291da177e4SLinus Torvalds if (mapping && !spin_trylock(&mapping->i_mmap_lock)) { 1301da177e4SLinus Torvalds spin_unlock(&mm->page_table_lock); 1311da177e4SLinus Torvalds spin_lock(&mapping->i_mmap_lock); 1321da177e4SLinus Torvalds spin_lock(&mm->page_table_lock); 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds src = get_one_pte_map_nested(mm, old_addr); 1351da177e4SLinus Torvalds } 1361da177e4SLinus Torvalds /* 1371da177e4SLinus Torvalds * Since alloc_one_pte_map can drop and re-acquire 1381da177e4SLinus Torvalds * page_table_lock, we should re-check the src entry... 1391da177e4SLinus Torvalds */ 1401da177e4SLinus Torvalds if (src) { 1411da177e4SLinus Torvalds if (dst) { 1421da177e4SLinus Torvalds pte_t pte; 1431da177e4SLinus Torvalds pte = ptep_clear_flush(vma, old_addr, src); 144*8b1f3124SNick Piggin 1459a61c349SNick Piggin /* ZERO_PAGE can be dependant on virtual addr */ 146*8b1f3124SNick Piggin pte = move_pte(pte, new_vma->vm_page_prot, 147*8b1f3124SNick Piggin old_addr, new_addr); 1481da177e4SLinus Torvalds set_pte_at(mm, new_addr, dst, pte); 1491da177e4SLinus Torvalds } else 1501da177e4SLinus Torvalds error = -ENOMEM; 1511da177e4SLinus Torvalds pte_unmap_nested(src); 1521da177e4SLinus Torvalds } 1531da177e4SLinus Torvalds if (dst) 1541da177e4SLinus Torvalds pte_unmap(dst); 1551da177e4SLinus Torvalds } 1561da177e4SLinus Torvalds spin_unlock(&mm->page_table_lock); 1571da177e4SLinus Torvalds if (mapping) 1581da177e4SLinus Torvalds spin_unlock(&mapping->i_mmap_lock); 1591da177e4SLinus Torvalds return error; 1601da177e4SLinus Torvalds } 1611da177e4SLinus Torvalds 1621da177e4SLinus Torvalds static unsigned long move_page_tables(struct vm_area_struct *vma, 1631da177e4SLinus Torvalds unsigned long old_addr, struct vm_area_struct *new_vma, 1641da177e4SLinus Torvalds unsigned long new_addr, unsigned long len) 1651da177e4SLinus Torvalds { 1661da177e4SLinus Torvalds unsigned long offset; 1671da177e4SLinus Torvalds 1681da177e4SLinus Torvalds flush_cache_range(vma, old_addr, old_addr + len); 1691da177e4SLinus Torvalds 1701da177e4SLinus Torvalds /* 1711da177e4SLinus Torvalds * This is not the clever way to do this, but we're taking the 1721da177e4SLinus Torvalds * easy way out on the assumption that most remappings will be 1731da177e4SLinus Torvalds * only a few pages.. This also makes error recovery easier. 1741da177e4SLinus Torvalds */ 1751da177e4SLinus Torvalds for (offset = 0; offset < len; offset += PAGE_SIZE) { 1761da177e4SLinus Torvalds if (move_one_page(vma, old_addr + offset, 1771da177e4SLinus Torvalds new_vma, new_addr + offset) < 0) 1781da177e4SLinus Torvalds break; 1791da177e4SLinus Torvalds cond_resched(); 1801da177e4SLinus Torvalds } 1811da177e4SLinus Torvalds return offset; 1821da177e4SLinus Torvalds } 1831da177e4SLinus Torvalds 1841da177e4SLinus Torvalds static unsigned long move_vma(struct vm_area_struct *vma, 1851da177e4SLinus Torvalds unsigned long old_addr, unsigned long old_len, 1861da177e4SLinus Torvalds unsigned long new_len, unsigned long new_addr) 1871da177e4SLinus Torvalds { 1881da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 1891da177e4SLinus Torvalds struct vm_area_struct *new_vma; 1901da177e4SLinus Torvalds unsigned long vm_flags = vma->vm_flags; 1911da177e4SLinus Torvalds unsigned long new_pgoff; 1921da177e4SLinus Torvalds unsigned long moved_len; 1931da177e4SLinus Torvalds unsigned long excess = 0; 1941da177e4SLinus Torvalds int split = 0; 1951da177e4SLinus Torvalds 1961da177e4SLinus Torvalds /* 1971da177e4SLinus Torvalds * We'd prefer to avoid failure later on in do_munmap: 1981da177e4SLinus Torvalds * which may split one vma into three before unmapping. 1991da177e4SLinus Torvalds */ 2001da177e4SLinus Torvalds if (mm->map_count >= sysctl_max_map_count - 3) 2011da177e4SLinus Torvalds return -ENOMEM; 2021da177e4SLinus Torvalds 2031da177e4SLinus Torvalds new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT); 2041da177e4SLinus Torvalds new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff); 2051da177e4SLinus Torvalds if (!new_vma) 2061da177e4SLinus Torvalds return -ENOMEM; 2071da177e4SLinus Torvalds 2081da177e4SLinus Torvalds moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len); 2091da177e4SLinus Torvalds if (moved_len < old_len) { 2101da177e4SLinus Torvalds /* 2111da177e4SLinus Torvalds * On error, move entries back from new area to old, 2121da177e4SLinus Torvalds * which will succeed since page tables still there, 2131da177e4SLinus Torvalds * and then proceed to unmap new area instead of old. 2141da177e4SLinus Torvalds */ 2151da177e4SLinus Torvalds move_page_tables(new_vma, new_addr, vma, old_addr, moved_len); 2161da177e4SLinus Torvalds vma = new_vma; 2171da177e4SLinus Torvalds old_len = new_len; 2181da177e4SLinus Torvalds old_addr = new_addr; 2191da177e4SLinus Torvalds new_addr = -ENOMEM; 2201da177e4SLinus Torvalds } 2211da177e4SLinus Torvalds 2221da177e4SLinus Torvalds /* Conceal VM_ACCOUNT so old reservation is not undone */ 2231da177e4SLinus Torvalds if (vm_flags & VM_ACCOUNT) { 2241da177e4SLinus Torvalds vma->vm_flags &= ~VM_ACCOUNT; 2251da177e4SLinus Torvalds excess = vma->vm_end - vma->vm_start - old_len; 2261da177e4SLinus Torvalds if (old_addr > vma->vm_start && 2271da177e4SLinus Torvalds old_addr + old_len < vma->vm_end) 2281da177e4SLinus Torvalds split = 1; 2291da177e4SLinus Torvalds } 2301da177e4SLinus Torvalds 23171799062SKirill Korotaev /* 23271799062SKirill Korotaev * if we failed to move page tables we still do total_vm increment 23371799062SKirill Korotaev * since do_munmap() will decrement it by old_len == new_len 23471799062SKirill Korotaev */ 23571799062SKirill Korotaev mm->total_vm += new_len >> PAGE_SHIFT; 2361c5ad845SHugh Dickins __vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT); 23771799062SKirill Korotaev 2381da177e4SLinus Torvalds if (do_munmap(mm, old_addr, old_len) < 0) { 2391da177e4SLinus Torvalds /* OOM: unable to split vma, just get accounts right */ 2401da177e4SLinus Torvalds vm_unacct_memory(excess >> PAGE_SHIFT); 2411da177e4SLinus Torvalds excess = 0; 2421da177e4SLinus Torvalds } 2431da177e4SLinus Torvalds 2441da177e4SLinus Torvalds /* Restore VM_ACCOUNT if one or two pieces of vma left */ 2451da177e4SLinus Torvalds if (excess) { 2461da177e4SLinus Torvalds vma->vm_flags |= VM_ACCOUNT; 2471da177e4SLinus Torvalds if (split) 2481da177e4SLinus Torvalds vma->vm_next->vm_flags |= VM_ACCOUNT; 2491da177e4SLinus Torvalds } 2501da177e4SLinus Torvalds 2511da177e4SLinus Torvalds if (vm_flags & VM_LOCKED) { 2521da177e4SLinus Torvalds mm->locked_vm += new_len >> PAGE_SHIFT; 2531da177e4SLinus Torvalds if (new_len > old_len) 2541da177e4SLinus Torvalds make_pages_present(new_addr + old_len, 2551da177e4SLinus Torvalds new_addr + new_len); 2561da177e4SLinus Torvalds } 2571da177e4SLinus Torvalds 2581da177e4SLinus Torvalds return new_addr; 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 2611da177e4SLinus Torvalds /* 2621da177e4SLinus Torvalds * Expand (or shrink) an existing mapping, potentially moving it at the 2631da177e4SLinus Torvalds * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) 2641da177e4SLinus Torvalds * 2651da177e4SLinus Torvalds * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise 2661da177e4SLinus Torvalds * This option implies MREMAP_MAYMOVE. 2671da177e4SLinus Torvalds */ 2681da177e4SLinus Torvalds unsigned long do_mremap(unsigned long addr, 2691da177e4SLinus Torvalds unsigned long old_len, unsigned long new_len, 2701da177e4SLinus Torvalds unsigned long flags, unsigned long new_addr) 2711da177e4SLinus Torvalds { 2721da177e4SLinus Torvalds struct vm_area_struct *vma; 2731da177e4SLinus Torvalds unsigned long ret = -EINVAL; 2741da177e4SLinus Torvalds unsigned long charged = 0; 2751da177e4SLinus Torvalds 2761da177e4SLinus Torvalds if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE)) 2771da177e4SLinus Torvalds goto out; 2781da177e4SLinus Torvalds 2791da177e4SLinus Torvalds if (addr & ~PAGE_MASK) 2801da177e4SLinus Torvalds goto out; 2811da177e4SLinus Torvalds 2821da177e4SLinus Torvalds old_len = PAGE_ALIGN(old_len); 2831da177e4SLinus Torvalds new_len = PAGE_ALIGN(new_len); 2841da177e4SLinus Torvalds 2851da177e4SLinus Torvalds /* 2861da177e4SLinus Torvalds * We allow a zero old-len as a special case 2871da177e4SLinus Torvalds * for DOS-emu "duplicate shm area" thing. But 2881da177e4SLinus Torvalds * a zero new-len is nonsensical. 2891da177e4SLinus Torvalds */ 2901da177e4SLinus Torvalds if (!new_len) 2911da177e4SLinus Torvalds goto out; 2921da177e4SLinus Torvalds 2931da177e4SLinus Torvalds /* new_addr is only valid if MREMAP_FIXED is specified */ 2941da177e4SLinus Torvalds if (flags & MREMAP_FIXED) { 2951da177e4SLinus Torvalds if (new_addr & ~PAGE_MASK) 2961da177e4SLinus Torvalds goto out; 2971da177e4SLinus Torvalds if (!(flags & MREMAP_MAYMOVE)) 2981da177e4SLinus Torvalds goto out; 2991da177e4SLinus Torvalds 3001da177e4SLinus Torvalds if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len) 3011da177e4SLinus Torvalds goto out; 3021da177e4SLinus Torvalds 3031da177e4SLinus Torvalds /* Check if the location we're moving into overlaps the 3041da177e4SLinus Torvalds * old location at all, and fail if it does. 3051da177e4SLinus Torvalds */ 3061da177e4SLinus Torvalds if ((new_addr <= addr) && (new_addr+new_len) > addr) 3071da177e4SLinus Torvalds goto out; 3081da177e4SLinus Torvalds 3091da177e4SLinus Torvalds if ((addr <= new_addr) && (addr+old_len) > new_addr) 3101da177e4SLinus Torvalds goto out; 3111da177e4SLinus Torvalds 3121da177e4SLinus Torvalds ret = do_munmap(current->mm, new_addr, new_len); 3131da177e4SLinus Torvalds if (ret) 3141da177e4SLinus Torvalds goto out; 3151da177e4SLinus Torvalds } 3161da177e4SLinus Torvalds 3171da177e4SLinus Torvalds /* 3181da177e4SLinus Torvalds * Always allow a shrinking remap: that just unmaps 3191da177e4SLinus Torvalds * the unnecessary pages.. 3201da177e4SLinus Torvalds * do_munmap does all the needed commit accounting 3211da177e4SLinus Torvalds */ 3221da177e4SLinus Torvalds if (old_len >= new_len) { 3231da177e4SLinus Torvalds ret = do_munmap(current->mm, addr+new_len, old_len - new_len); 3241da177e4SLinus Torvalds if (ret && old_len != new_len) 3251da177e4SLinus Torvalds goto out; 3261da177e4SLinus Torvalds ret = addr; 3271da177e4SLinus Torvalds if (!(flags & MREMAP_FIXED) || (new_addr == addr)) 3281da177e4SLinus Torvalds goto out; 3291da177e4SLinus Torvalds old_len = new_len; 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds /* 3331da177e4SLinus Torvalds * Ok, we need to grow.. or relocate. 3341da177e4SLinus Torvalds */ 3351da177e4SLinus Torvalds ret = -EFAULT; 3361da177e4SLinus Torvalds vma = find_vma(current->mm, addr); 3371da177e4SLinus Torvalds if (!vma || vma->vm_start > addr) 3381da177e4SLinus Torvalds goto out; 3391da177e4SLinus Torvalds if (is_vm_hugetlb_page(vma)) { 3401da177e4SLinus Torvalds ret = -EINVAL; 3411da177e4SLinus Torvalds goto out; 3421da177e4SLinus Torvalds } 3431da177e4SLinus Torvalds /* We can't remap across vm area boundaries */ 3441da177e4SLinus Torvalds if (old_len > vma->vm_end - addr) 3451da177e4SLinus Torvalds goto out; 3461da177e4SLinus Torvalds if (vma->vm_flags & VM_DONTEXPAND) { 3471da177e4SLinus Torvalds if (new_len > old_len) 3481da177e4SLinus Torvalds goto out; 3491da177e4SLinus Torvalds } 3501da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) { 3511da177e4SLinus Torvalds unsigned long locked, lock_limit; 3521da177e4SLinus Torvalds locked = current->mm->locked_vm << PAGE_SHIFT; 3531da177e4SLinus Torvalds lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur; 3541da177e4SLinus Torvalds locked += new_len - old_len; 3551da177e4SLinus Torvalds ret = -EAGAIN; 3561da177e4SLinus Torvalds if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 3571da177e4SLinus Torvalds goto out; 3581da177e4SLinus Torvalds } 359119f657cSakpm@osdl.org if (!may_expand_vm(current->mm, (new_len - old_len) >> PAGE_SHIFT)) { 3601da177e4SLinus Torvalds ret = -ENOMEM; 3611da177e4SLinus Torvalds goto out; 362119f657cSakpm@osdl.org } 3631da177e4SLinus Torvalds 3641da177e4SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) { 3651da177e4SLinus Torvalds charged = (new_len - old_len) >> PAGE_SHIFT; 3661da177e4SLinus Torvalds if (security_vm_enough_memory(charged)) 3671da177e4SLinus Torvalds goto out_nc; 3681da177e4SLinus Torvalds } 3691da177e4SLinus Torvalds 3701da177e4SLinus Torvalds /* old_len exactly to the end of the area.. 3711da177e4SLinus Torvalds * And we're not relocating the area. 3721da177e4SLinus Torvalds */ 3731da177e4SLinus Torvalds if (old_len == vma->vm_end - addr && 3741da177e4SLinus Torvalds !((flags & MREMAP_FIXED) && (addr != new_addr)) && 3751da177e4SLinus Torvalds (old_len != new_len || !(flags & MREMAP_MAYMOVE))) { 3761da177e4SLinus Torvalds unsigned long max_addr = TASK_SIZE; 3771da177e4SLinus Torvalds if (vma->vm_next) 3781da177e4SLinus Torvalds max_addr = vma->vm_next->vm_start; 3791da177e4SLinus Torvalds /* can we just expand the current mapping? */ 3801da177e4SLinus Torvalds if (max_addr - addr >= new_len) { 3811da177e4SLinus Torvalds int pages = (new_len - old_len) >> PAGE_SHIFT; 3821da177e4SLinus Torvalds 3831da177e4SLinus Torvalds vma_adjust(vma, vma->vm_start, 3841da177e4SLinus Torvalds addr + new_len, vma->vm_pgoff, NULL); 3851da177e4SLinus Torvalds 3861da177e4SLinus Torvalds current->mm->total_vm += pages; 3871da177e4SLinus Torvalds __vm_stat_account(vma->vm_mm, vma->vm_flags, 3881da177e4SLinus Torvalds vma->vm_file, pages); 3891da177e4SLinus Torvalds if (vma->vm_flags & VM_LOCKED) { 3901da177e4SLinus Torvalds current->mm->locked_vm += pages; 3911da177e4SLinus Torvalds make_pages_present(addr + old_len, 3921da177e4SLinus Torvalds addr + new_len); 3931da177e4SLinus Torvalds } 3941da177e4SLinus Torvalds ret = addr; 3951da177e4SLinus Torvalds goto out; 3961da177e4SLinus Torvalds } 3971da177e4SLinus Torvalds } 3981da177e4SLinus Torvalds 3991da177e4SLinus Torvalds /* 4001da177e4SLinus Torvalds * We weren't able to just expand or shrink the area, 4011da177e4SLinus Torvalds * we need to create a new one and move it.. 4021da177e4SLinus Torvalds */ 4031da177e4SLinus Torvalds ret = -ENOMEM; 4041da177e4SLinus Torvalds if (flags & MREMAP_MAYMOVE) { 4051da177e4SLinus Torvalds if (!(flags & MREMAP_FIXED)) { 4061da177e4SLinus Torvalds unsigned long map_flags = 0; 4071da177e4SLinus Torvalds if (vma->vm_flags & VM_MAYSHARE) 4081da177e4SLinus Torvalds map_flags |= MAP_SHARED; 4091da177e4SLinus Torvalds 4101da177e4SLinus Torvalds new_addr = get_unmapped_area(vma->vm_file, 0, new_len, 4111da177e4SLinus Torvalds vma->vm_pgoff, map_flags); 4121da177e4SLinus Torvalds ret = new_addr; 4131da177e4SLinus Torvalds if (new_addr & ~PAGE_MASK) 4141da177e4SLinus Torvalds goto out; 4151da177e4SLinus Torvalds } 4161da177e4SLinus Torvalds ret = move_vma(vma, addr, old_len, new_len, new_addr); 4171da177e4SLinus Torvalds } 4181da177e4SLinus Torvalds out: 4191da177e4SLinus Torvalds if (ret & ~PAGE_MASK) 4201da177e4SLinus Torvalds vm_unacct_memory(charged); 4211da177e4SLinus Torvalds out_nc: 4221da177e4SLinus Torvalds return ret; 4231da177e4SLinus Torvalds } 4241da177e4SLinus Torvalds 4251da177e4SLinus Torvalds asmlinkage unsigned long sys_mremap(unsigned long addr, 4261da177e4SLinus Torvalds unsigned long old_len, unsigned long new_len, 4271da177e4SLinus Torvalds unsigned long flags, unsigned long new_addr) 4281da177e4SLinus Torvalds { 4291da177e4SLinus Torvalds unsigned long ret; 4301da177e4SLinus Torvalds 4311da177e4SLinus Torvalds down_write(¤t->mm->mmap_sem); 4321da177e4SLinus Torvalds ret = do_mremap(addr, old_len, new_len, flags, new_addr); 4331da177e4SLinus Torvalds up_write(¤t->mm->mmap_sem); 4341da177e4SLinus Torvalds return ret; 4351da177e4SLinus Torvalds } 436