hwmon: (lm92) Convert to a new-style i2c driver
[linux-2.6.git] / mm / mremap.c
index a32fed4..08e3c7f 100644 (file)
@@ -13,6 +13,7 @@
 #include <linux/shm.h>
 #include <linux/mman.h>
 #include <linux/swap.h>
+#include <linux/capability.h>
 #include <linux/fs.h>
 #include <linux/highmem.h>
 #include <linux/security.h>
 #include <asm/cacheflush.h>
 #include <asm/tlbflush.h>
 
-static pte_t *get_one_pte_map_nested(struct mm_struct *mm, unsigned long addr)
-{
-       pgd_t *pgd;
-       pud_t *pud;
-       pmd_t *pmd;
-       pte_t *pte = NULL;
-
-       pgd = pgd_offset(mm, addr);
-       if (pgd_none_or_clear_bad(pgd))
-               goto end;
-
-       pud = pud_offset(pgd, addr);
-       if (pud_none_or_clear_bad(pud))
-               goto end;
-
-       pmd = pmd_offset(pud, addr);
-       if (pmd_none_or_clear_bad(pmd))
-               goto end;
-
-       pte = pte_offset_map_nested(pmd, addr);
-       if (pte_none(*pte)) {
-               pte_unmap_nested(pte);
-               pte = NULL;
-       }
-end:
-       return pte;
-}
-
-static pte_t *get_one_pte_map(struct mm_struct *mm, unsigned long addr)
+static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
 {
        pgd_t *pgd;
        pud_t *pud;
@@ -68,35 +41,39 @@ static pte_t *get_one_pte_map(struct mm_struct *mm, unsigned long addr)
        if (pmd_none_or_clear_bad(pmd))
                return NULL;
 
-       return pte_offset_map(pmd, addr);
+       return pmd;
 }
 
-static inline pte_t *alloc_one_pte_map(struct mm_struct *mm, unsigned long addr)
+static pmd_t *alloc_new_pmd(struct mm_struct *mm, unsigned long addr)
 {
        pgd_t *pgd;
        pud_t *pud;
        pmd_t *pmd;
-       pte_t *pte = NULL;
 
        pgd = pgd_offset(mm, addr);
-
        pud = pud_alloc(mm, pgd, addr);
        if (!pud)
                return NULL;
+
        pmd = pmd_alloc(mm, pud, addr);
-       if (pmd)
-               pte = pte_alloc_map(mm, pmd, addr);
-       return pte;
+       if (!pmd)
+               return NULL;
+
+       if (!pmd_present(*pmd) && __pte_alloc(mm, pmd, addr))
+               return NULL;
+
+       return pmd;
 }
 
-static int
-move_one_page(struct vm_area_struct *vma, unsigned long old_addr,
-               struct vm_area_struct *new_vma, unsigned long new_addr)
+static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
+               unsigned long old_addr, unsigned long old_end,
+               struct vm_area_struct *new_vma, pmd_t *new_pmd,
+               unsigned long new_addr)
 {
        struct address_space *mapping = NULL;
        struct mm_struct *mm = vma->vm_mm;
-       int error = 0;
-       pte_t *src, *dst;
+       pte_t *old_pte, *new_pte, pte;
+       spinlock_t *old_ptl, *new_ptl;
 
        if (vma->vm_file) {
                /*
@@ -111,74 +88,70 @@ move_one_page(struct vm_area_struct *vma, unsigned long old_addr,
                    new_vma->vm_truncate_count != vma->vm_truncate_count)
                        new_vma->vm_truncate_count = 0;
        }
-       spin_lock(&mm->page_table_lock);
 
-       src = get_one_pte_map_nested(mm, old_addr);
-       if (src) {
-               /*
-                * Look to see whether alloc_one_pte_map needs to perform a
-                * memory allocation.  If it does then we need to drop the
-                * atomic kmap
-                */
-               dst = get_one_pte_map(mm, new_addr);
-               if (unlikely(!dst)) {
-                       pte_unmap_nested(src);
-                       if (mapping)
-                               spin_unlock(&mapping->i_mmap_lock);
-                       dst = alloc_one_pte_map(mm, new_addr);
-                       if (mapping && !spin_trylock(&mapping->i_mmap_lock)) {
-                               spin_unlock(&mm->page_table_lock);
-                               spin_lock(&mapping->i_mmap_lock);
-                               spin_lock(&mm->page_table_lock);
-                       }
-                       src = get_one_pte_map_nested(mm, old_addr);
-               }
-               /*
-                * Since alloc_one_pte_map can drop and re-acquire
-                * page_table_lock, we should re-check the src entry...
-                */
-               if (src) {
-                       if (dst) {
-                               pte_t pte;
-                               pte = ptep_clear_flush(vma, old_addr, src);
-                               /* ZERO_PAGE can be dependant on virtual addr */
-                               if (pfn_valid(pte_pfn(pte)) &&
-                                       pte_page(pte) == ZERO_PAGE(old_addr))
-                                       pte = pte_wrprotect(mk_pte(ZERO_PAGE(new_addr), new_vma->vm_page_prot));
-                               set_pte_at(mm, new_addr, dst, pte);
-                       } else
-                               error = -ENOMEM;
-                       pte_unmap_nested(src);
-               }
-               if (dst)
-                       pte_unmap(dst);
+       /*
+        * We don't have to worry about the ordering of src and dst
+        * pte locks because exclusive mmap_sem prevents deadlock.
+        */
+       old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
+       new_pte = pte_offset_map_nested(new_pmd, new_addr);
+       new_ptl = pte_lockptr(mm, new_pmd);
+       if (new_ptl != old_ptl)
+               spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+       arch_enter_lazy_mmu_mode();
+
+       for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
+                                  new_pte++, new_addr += PAGE_SIZE) {
+               if (pte_none(*old_pte))
+                       continue;
+               pte = ptep_clear_flush(vma, old_addr, old_pte);
+               pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
+               set_pte_at(mm, new_addr, new_pte, pte);
        }
-       spin_unlock(&mm->page_table_lock);
+
+       arch_leave_lazy_mmu_mode();
+       if (new_ptl != old_ptl)
+               spin_unlock(new_ptl);
+       pte_unmap_nested(new_pte - 1);
+       pte_unmap_unlock(old_pte - 1, old_ptl);
        if (mapping)
                spin_unlock(&mapping->i_mmap_lock);
-       return error;
 }
 
-static unsigned long move_page_tables(struct vm_area_struct *vma,
+#define LATENCY_LIMIT  (64 * PAGE_SIZE)
+
+unsigned long move_page_tables(struct vm_area_struct *vma,
                unsigned long old_addr, struct vm_area_struct *new_vma,
                unsigned long new_addr, unsigned long len)
 {
-       unsigned long offset;
+       unsigned long extent, next, old_end;
+       pmd_t *old_pmd, *new_pmd;
 
-       flush_cache_range(vma, old_addr, old_addr + len);
+       old_end = old_addr + len;
+       flush_cache_range(vma, old_addr, old_end);
 
-       /*
-        * This is not the clever way to do this, but we're taking the
-        * easy way out on the assumption that most remappings will be
-        * only a few pages.. This also makes error recovery easier.
-        */
-       for (offset = 0; offset < len; offset += PAGE_SIZE) {
-               if (move_one_page(vma, old_addr + offset,
-                               new_vma, new_addr + offset) < 0)
-                       break;
+       for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
                cond_resched();
+               next = (old_addr + PMD_SIZE) & PMD_MASK;
+               if (next - 1 > old_end)
+                       next = old_end;
+               extent = next - old_addr;
+               old_pmd = get_old_pmd(vma->vm_mm, old_addr);
+               if (!old_pmd)
+                       continue;
+               new_pmd = alloc_new_pmd(vma->vm_mm, new_addr);
+               if (!new_pmd)
+                       break;
+               next = (new_addr + PMD_SIZE) & PMD_MASK;
+               if (extent > next - new_addr)
+                       extent = next - new_addr;
+               if (extent > LATENCY_LIMIT)
+                       extent = LATENCY_LIMIT;
+               move_ptes(vma, old_pmd, old_addr, old_addr + extent,
+                               new_vma, new_pmd, new_addr);
        }
-       return offset;
+
+       return len + old_addr - old_end;        /* how much done */
 }
 
 static unsigned long move_vma(struct vm_area_struct *vma,
@@ -191,6 +164,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
        unsigned long new_pgoff;
        unsigned long moved_len;
        unsigned long excess = 0;
+       unsigned long hiwater_vm;
        int split = 0;
 
        /*
@@ -229,17 +203,24 @@ static unsigned long move_vma(struct vm_area_struct *vma,
        }
 
        /*
-        * if we failed to move page tables we still do total_vm increment
-        * since do_munmap() will decrement it by old_len == new_len
+        * If we failed to move page tables we still do total_vm increment
+        * since do_munmap() will decrement it by old_len == new_len.
+        *
+        * Since total_vm is about to be raised artificially high for a
+        * moment, we need to restore high watermark afterwards: if stats
+        * are taken meanwhile, total_vm and hiwater_vm appear too high.
+        * If this were a serious issue, we'd add a flag to do_munmap().
         */
+       hiwater_vm = mm->hiwater_vm;
        mm->total_vm += new_len >> PAGE_SHIFT;
-       __vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
+       vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
 
        if (do_munmap(mm, old_addr, old_len) < 0) {
                /* OOM: unable to split vma, just get accounts right */
                vm_unacct_memory(excess >> PAGE_SHIFT);
                excess = 0;
        }
+       mm->hiwater_vm = hiwater_vm;
 
        /* Restore VM_ACCOUNT if one or two pieces of vma left */
        if (excess) {
@@ -269,6 +250,7 @@ unsigned long do_mremap(unsigned long addr,
        unsigned long old_len, unsigned long new_len,
        unsigned long flags, unsigned long new_addr)
 {
+       struct mm_struct *mm = current->mm;
        struct vm_area_struct *vma;
        unsigned long ret = -EINVAL;
        unsigned long charged = 0;
@@ -309,7 +291,11 @@ unsigned long do_mremap(unsigned long addr,
                if ((addr <= new_addr) && (addr+old_len) > new_addr)
                        goto out;
 
-               ret = do_munmap(current->mm, new_addr, new_len);
+               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;
        }
@@ -320,7 +306,7 @@ unsigned long do_mremap(unsigned long addr,
         * do_munmap does all the needed commit accounting
         */
        if (old_len >= new_len) {
-               ret = do_munmap(current->mm, addr+new_len, old_len - new_len);
+               ret = do_munmap(mm, addr+new_len, old_len - new_len);
                if (ret && old_len != new_len)
                        goto out;
                ret = addr;
@@ -333,7 +319,7 @@ unsigned long do_mremap(unsigned long addr,
         * Ok, we need to grow..  or relocate.
         */
        ret = -EFAULT;
-       vma = find_vma(current->mm, addr);
+       vma = find_vma(mm, addr);
        if (!vma || vma->vm_start > addr)
                goto out;
        if (is_vm_hugetlb_page(vma)) {
@@ -343,20 +329,20 @@ unsigned long do_mremap(unsigned long addr,
        /* We can't remap across vm area boundaries */
        if (old_len > vma->vm_end - addr)
                goto out;
-       if (vma->vm_flags & VM_DONTEXPAND) {
+       if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
                if (new_len > old_len)
                        goto out;
        }
        if (vma->vm_flags & VM_LOCKED) {
                unsigned long locked, lock_limit;
-               locked = current->mm->locked_vm << PAGE_SHIFT;
+               locked = mm->locked_vm << PAGE_SHIFT;
                lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
                locked += new_len - old_len;
                ret = -EAGAIN;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        goto out;
        }
-       if (!may_expand_vm(current->mm, (new_len - old_len) >> PAGE_SHIFT)) {
+       if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT)) {
                ret = -ENOMEM;
                goto out;
        }
@@ -383,11 +369,10 @@ unsigned long do_mremap(unsigned long addr,
                        vma_adjust(vma, vma->vm_start,
                                addr + new_len, vma->vm_pgoff, NULL);
 
-                       current->mm->total_vm += pages;
-                       __vm_stat_account(vma->vm_mm, vma->vm_flags,
-                                                       vma->vm_file, pages);
+                       mm->total_vm += pages;
+                       vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
                        if (vma->vm_flags & VM_LOCKED) {
-                               current->mm->locked_vm += pages;
+                               mm->locked_vm += pages;
                                make_pages_present(addr + old_len,
                                                   addr + new_len);
                        }
@@ -409,8 +394,13 @@ unsigned long do_mremap(unsigned long addr,
 
                        new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
                                                vma->vm_pgoff, map_flags);
-                       ret = new_addr;
-                       if (new_addr & ~PAGE_MASK)
+                       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);