V4L/DVB (4346): V4L2 conversion: radio_aimslab
[safe/jmp/linux-2.6] / mm / mmap.c
index fa11d91..d799d89 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -13,6 +13,7 @@
 #include <linux/pagemap.h>
 #include <linux/swap.h>
 #include <linux/syscalls.h>
+#include <linux/capability.h>
 #include <linux/init.h>
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <asm/cacheflush.h>
 #include <asm/tlb.h>
 
+#ifndef arch_mmap_check
+#define arch_mmap_check(addr, len, flags)      (0)
+#endif
+
 static void unmap_region(struct mm_struct *mm,
                struct vm_area_struct *vma, struct vm_area_struct *prev,
                unsigned long start, unsigned long end);
@@ -59,6 +64,13 @@ pgprot_t protection_map[16] = {
        __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
 };
 
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+       return protection_map[vm_flags &
+                               (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+
 int sysctl_overcommit_memory = OVERCOMMIT_GUESS;  /* heuristic overcommit */
 int sysctl_overcommit_ratio = 50;      /* default is 50% */
 int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
@@ -95,7 +107,7 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
        if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
                unsigned long n;
 
-               free = get_page_cache_size();
+               free = global_page_state(NR_FILE_PAGES);
                free += nr_swap_pages;
 
                /*
@@ -120,14 +132,26 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
                 * only call if we're about to fail.
                 */
                n = nr_free_pages();
+
+               /*
+                * Leave reserved pages. The pages are not for anonymous pages.
+                */
+               if (n <= totalreserve_pages)
+                       goto error;
+               else
+                       n -= totalreserve_pages;
+
+               /*
+                * Leave the last 3% for root
+                */
                if (!cap_sys_admin)
                        n -= n / 32;
                free += n;
 
                if (free > pages)
                        return 0;
-               vm_unacct_memory(pages);
-               return -ENOMEM;
+
+               goto error;
        }
 
        allowed = (totalram_pages - hugetlb_total_pages())
@@ -149,16 +173,12 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
         */
        if (atomic_read(&vm_committed_space) < (long)allowed)
                return 0;
-
+error:
        vm_unacct_memory(pages);
 
        return -ENOMEM;
 }
 
-EXPORT_SYMBOL(sysctl_overcommit_memory);
-EXPORT_SYMBOL(sysctl_overcommit_ratio);
-EXPORT_SYMBOL(sysctl_max_map_count);
-EXPORT_SYMBOL(vm_committed_space);
 EXPORT_SYMBOL(__vm_enough_memory);
 
 /*
@@ -181,26 +201,36 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma,
 }
 
 /*
- * Remove one vm structure and free it.
+ * Unlink a file-based vm structure from its prio_tree, to hide
+ * vma from rmap and vmtruncate before freeing its page tables.
  */
-static void remove_vm_struct(struct vm_area_struct *vma)
+void unlink_file_vma(struct vm_area_struct *vma)
 {
        struct file *file = vma->vm_file;
 
-       might_sleep();
        if (file) {
                struct address_space *mapping = file->f_mapping;
                spin_lock(&mapping->i_mmap_lock);
                __remove_shared_vm_struct(vma, file, mapping);
                spin_unlock(&mapping->i_mmap_lock);
        }
+}
+
+/*
+ * Close a vm structure and free it, returning the next.
+ */
+static struct vm_area_struct *remove_vma(struct vm_area_struct *vma)
+{
+       struct vm_area_struct *next = vma->vm_next;
+
+       might_sleep();
        if (vma->vm_ops && vma->vm_ops->close)
                vma->vm_ops->close(vma);
-       if (file)
-               fput(file);
-       anon_vma_unlink(vma);
+       if (vma->vm_file)
+               fput(vma->vm_file);
        mpol_free(vma_policy(vma));
        kmem_cache_free(vm_area_cachep, vma);
+       return next;
 }
 
 asmlinkage unsigned long sys_brk(unsigned long brk)
@@ -213,6 +243,17 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
 
        if (brk < mm->end_code)
                goto out;
+
+       /*
+        * Check against rlimit here. If this check is done later after the test
+        * of oldbrk with newbrk then it can escape the test and let the data
+        * segment grow beyond its set limit the in case where the limit is
+        * not page aligned -Ram Gupta
+        */
+       rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
+       if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
+               goto out;
+
        newbrk = PAGE_ALIGN(brk);
        oldbrk = PAGE_ALIGN(mm->brk);
        if (oldbrk == newbrk)
@@ -225,11 +266,6 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
                goto out;
        }
 
-       /* Check against rlimit.. */
-       rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
-       if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
-               goto out;
-
        /* Check against existing mmap mappings. */
        if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
                goto out;
@@ -287,8 +323,7 @@ void validate_mm(struct mm_struct *mm)
        i = browse_rb(&mm->mm_rb);
        if (i != mm->map_count)
                printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
-       if (bug)
-               BUG();
+       BUG_ON(bug);
 }
 #else
 #define validate_mm(mm) do { } while (0)
@@ -425,8 +460,7 @@ __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
        struct rb_node ** rb_link, * rb_parent;
 
        __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
-       if (__vma && __vma->vm_start < vma->vm_end)
-               BUG();
+       BUG_ON(__vma && __vma->vm_start < vma->vm_end);
        __vma_link(mm, vma, prev, rb_link, rb_parent);
        mm->map_count++;
 }
@@ -605,7 +639,7 @@ again:                      remove_next = 1 + (end > next->vm_end);
  * If the vma has a ->close operation then the driver probably needs to release
  * per-vma resources, so we don't attempt to merge those.
  */
-#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED)
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)
 
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
                        struct file *file, unsigned long vm_flags)
@@ -806,8 +840,7 @@ try_prev:
         * (e.g. stash info in next's anon_vma_node when assigning
         * an anon_vma, or when trying vma_merge).  Another time.
         */
-       if (find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma)
-               BUG();
+       BUG_ON(find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma);
        if (!near)
                goto none;
 
@@ -832,20 +865,12 @@ none:
 }
 
 #ifdef CONFIG_PROC_FS
-void __vm_stat_account(struct mm_struct *mm, unsigned long flags,
+void vm_stat_account(struct mm_struct *mm, unsigned long flags,
                                                struct file *file, long pages)
 {
        const unsigned long stack_flags
                = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN);
 
-#ifdef CONFIG_HUGETLB
-       if (flags & VM_HUGETLB) {
-               if (!(flags & VM_DONTCOPY))
-                       mm->shared_vm += pages;
-               return;
-       }
-#endif /* CONFIG_HUGETLB */
-
        if (file) {
                mm->shared_vm += pages;
                if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC)
@@ -899,6 +924,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
        if (!len)
                return -EINVAL;
 
+       error = arch_mmap_check(addr, len, flags);
+       if (error)
+               return error;
+
        /* Careful about overflows.. */
        len = PAGE_ALIGN(len);
        if (!len || len > TASK_SIZE)
@@ -1041,18 +1070,18 @@ munmap_back:
         * specific mapper. the address has already been validated, but
         * not unmapped, but the maps are removed from the list.
         */
-       vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+       vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
        if (!vma) {
                error = -ENOMEM;
                goto unacct_error;
        }
-       memset(vma, 0, sizeof(*vma));
 
        vma->vm_mm = mm;
        vma->vm_start = addr;
        vma->vm_end = addr + len;
        vma->vm_flags = vm_flags;
-       vma->vm_page_prot = protection_map[vm_flags & 0x0f];
+       vma->vm_page_prot = protection_map[vm_flags &
+                               (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
        vma->vm_pgoff = pgoff;
 
        if (file) {
@@ -1076,6 +1105,12 @@ munmap_back:
                        goto free_vma;
        }
 
+       /* Don't make the VMA automatically writable if it's shared, but the
+        * backer wishes to know when pages are first written to */
+       if (vma->vm_ops && vma->vm_ops->page_mkwrite)
+               vma->vm_page_prot =
+                       protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)];
+
        /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
         * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
         * that memory reservation must be checked; but that reservation
@@ -1110,7 +1145,7 @@ munmap_back:
        }
 out:   
        mm->total_vm += len >> PAGE_SHIFT;
-       __vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
+       vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);
        if (vm_flags & VM_LOCKED) {
                mm->locked_vm += len >> PAGE_SHIFT;
                make_pages_present(addr, addr + len);
@@ -1475,15 +1510,19 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un
        mm->total_vm += grow;
        if (vma->vm_flags & VM_LOCKED)
                mm->locked_vm += grow;
-       __vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
+       vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow);
        return 0;
 }
 
-#ifdef CONFIG_STACK_GROWSUP
+#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
 /*
- * vma is the first one with address > vma->vm_end.  Have to extend vma.
+ * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
+ * vma is the last one with address > vma->vm_end.  Have to extend vma.
  */
-int expand_stack(struct vm_area_struct * vma, unsigned long address)
+#ifndef CONFIG_IA64
+static inline
+#endif
+int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 {
        int error;
 
@@ -1521,6 +1560,13 @@ int expand_stack(struct vm_area_struct * vma, unsigned long address)
        anon_vma_unlock(vma);
        return error;
 }
+#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
+
+#ifdef CONFIG_STACK_GROWSUP
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+       return expand_upwards(vma, address);
+}
 
 struct vm_area_struct *
 find_extend_vma(struct mm_struct *mm, unsigned long addr)
@@ -1603,36 +1649,24 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr)
 }
 #endif
 
-/* Normal function to fix up a mapping
- * This function is the default for when an area has no specific
- * function.  This may be used as part of a more specific routine.
- *
- * By the time this function is called, the area struct has been
- * removed from the process mapping list.
- */
-static void unmap_vma(struct mm_struct *mm, struct vm_area_struct *area)
-{
-       size_t len = area->vm_end - area->vm_start;
-
-       area->vm_mm->total_vm -= len >> PAGE_SHIFT;
-       if (area->vm_flags & VM_LOCKED)
-               area->vm_mm->locked_vm -= len >> PAGE_SHIFT;
-       vm_stat_unaccount(area);
-       remove_vm_struct(area);
-}
-
 /*
- * Update the VMA and inode share lists.
- *
- * Ok - we have the memory areas we should free on the 'free' list,
+ * Ok - we have the memory areas we should free on the vma list,
  * so release them, and do the vma updates.
+ *
+ * Called with the mm semaphore held.
  */
-static void unmap_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
+static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma)
 {
+       /* Update high watermark before we lower total_vm */
+       update_hiwater_vm(mm);
        do {
-               struct vm_area_struct *next = vma->vm_next;
-               unmap_vma(mm, vma);
-               vma = next;
+               long nrpages = vma_pages(vma);
+
+               mm->total_vm -= nrpages;
+               if (vma->vm_flags & VM_LOCKED)
+                       mm->locked_vm -= nrpages;
+               vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages);
+               vma = remove_vma(vma);
        } while (vma);
        validate_mm(mm);
 }
@@ -1651,14 +1685,13 @@ static void unmap_region(struct mm_struct *mm,
        unsigned long nr_accounted = 0;
 
        lru_add_drain();
-       spin_lock(&mm->page_table_lock);
        tlb = tlb_gather_mmu(mm, 0);
-       unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL);
+       update_hiwater_rss(mm);
+       unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL);
        vm_unacct_memory(nr_accounted);
        free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS,
                                 next? next->vm_start: 0);
        tlb_finish_mmu(tlb, start, end);
-       spin_unlock(&mm->page_table_lock);
 }
 
 /*
@@ -1799,7 +1832,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
        unmap_region(mm, vma, prev, start, end);
 
        /* Fix up all other VM information */
-       unmap_vma_list(mm, vma);
+       remove_vma_list(mm, vma);
 
        return 0;
 }
@@ -1821,7 +1854,7 @@ asmlinkage long sys_munmap(unsigned long addr, size_t len)
 
 static inline void verify_mm_writelocked(struct mm_struct *mm)
 {
-#ifdef CONFIG_DEBUG_KERNEL
+#ifdef CONFIG_DEBUG_VM
        if (unlikely(down_read_trylock(&mm->mmap_sem))) {
                WARN_ON(1);
                up_read(&mm->mmap_sem);
@@ -1841,6 +1874,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
        unsigned long flags;
        struct rb_node ** rb_link, * rb_parent;
        pgoff_t pgoff = addr >> PAGE_SHIFT;
+       int error;
 
        len = PAGE_ALIGN(len);
        if (!len)
@@ -1849,6 +1883,12 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
        if ((addr + len) > TASK_SIZE || (addr + len) < addr)
                return -EINVAL;
 
+       flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
+
+       error = arch_mmap_check(addr, len, flags);
+       if (error)
+               return error;
+
        /*
         * mlock MCL_FUTURE?
         */
@@ -1889,8 +1929,6 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
        if (security_vm_enough_memory(len >> PAGE_SHIFT))
                return -ENOMEM;
 
-       flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
-
        /* Can we just expand an old private anonymous mapping? */
        if (vma_merge(mm, prev, addr, addr + len, flags,
                                        NULL, NULL, pgoff, NULL))
@@ -1899,19 +1937,19 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
        /*
         * create a vma struct for an anonymous mapping
         */
-       vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+       vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
        if (!vma) {
                vm_unacct_memory(len >> PAGE_SHIFT);
                return -ENOMEM;
        }
-       memset(vma, 0, sizeof(*vma));
 
        vma->vm_mm = mm;
        vma->vm_start = addr;
        vma->vm_end = addr + len;
        vma->vm_pgoff = pgoff;
        vma->vm_flags = flags;
-       vma->vm_page_prot = protection_map[flags & 0x0f];
+       vma->vm_page_prot = protection_map[flags &
+                               (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
        vma_link(mm, vma, prev, rb_link, rb_parent);
 out:
        mm->total_vm += len >> PAGE_SHIFT;
@@ -1933,34 +1971,21 @@ void exit_mmap(struct mm_struct *mm)
        unsigned long end;
 
        lru_add_drain();
-
-       spin_lock(&mm->page_table_lock);
-
        flush_cache_mm(mm);
        tlb = tlb_gather_mmu(mm, 1);
+       /* Don't update_hiwater_rss(mm) here, do_exit already did */
        /* Use -1 here to ensure all VMAs in the mm are unmapped */
-       end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL);
+       end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
        vm_unacct_memory(nr_accounted);
        free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0);
        tlb_finish_mmu(tlb, 0, end);
 
-       mm->mmap = mm->mmap_cache = NULL;
-       mm->mm_rb = RB_ROOT;
-       set_mm_counter(mm, rss, 0);
-       mm->total_vm = 0;
-       mm->locked_vm = 0;
-
-       spin_unlock(&mm->page_table_lock);
-
        /*
-        * Walk the list again, actually closing and freeing it
-        * without holding any MM locks.
+        * Walk the list again, actually closing and freeing it,
+        * with preemption enabled, without holding any MM locks.
         */
-       while (vma) {
-               struct vm_area_struct *next = vma->vm_next;
-               remove_vm_struct(vma);
-               vma = next;
-       }
+       while (vma)
+               vma = remove_vma(vma);
 
        BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT);
 }