* Lock ordering in mm:
*
* inode->i_mutex (while writing or truncating, not reading or faulting)
- * inode->i_alloc_sem
- *
- * When a page fault occurs in writing from user to file, down_read
- * of mmap_sem nests within i_mutex; in sys_msync, i_mutex nests within
- * down_read of mmap_sem; i_mutex and down_write of mmap_sem are never
- * taken together; in truncation, i_mutex is taken outermost.
- *
- * mm->mmap_sem
- * page->flags PG_locked (lock_page)
- * mapping->i_mmap_lock
- * anon_vma->lock
- * mm->page_table_lock or pte_lock
- * zone->lru_lock (in mark_page_accessed, isolate_lru_page)
- * swap_lock (in swap_duplicate, swap_info_get)
- * mmlist_lock (in mmput, drain_mmlist and others)
- * mapping->private_lock (in __set_page_dirty_buffers)
- * inode_lock (in set_page_dirty's __mark_inode_dirty)
- * sb_lock (within inode_lock in fs/fs-writeback.c)
- * mapping->tree_lock (widely used, in set_page_dirty,
- * in arch-dependent flush_dcache_mmap_lock,
- * within inode_lock in __sync_single_inode)
+ * inode->i_alloc_sem (vmtruncate_range)
+ * mm->mmap_sem
+ * page->flags PG_locked (lock_page)
+ * mapping->i_mmap_lock
+ * anon_vma->lock
+ * mm->page_table_lock or pte_lock
+ * zone->lru_lock (in mark_page_accessed, isolate_lru_page)
+ * swap_lock (in swap_duplicate, swap_info_get)
+ * mmlist_lock (in mmput, drain_mmlist and others)
+ * mapping->private_lock (in __set_page_dirty_buffers)
+ * inode_lock (in set_page_dirty's __mark_inode_dirty)
+ * sb_lock (within inode_lock in fs/fs-writeback.c)
+ * mapping->tree_lock (widely used, in set_page_dirty,
+ * in arch-dependent flush_dcache_mmap_lock,
+ * within inode_lock in __sync_single_inode)
*/
#include <linux/mm.h>
#include <linux/rmap.h>
#include <linux/rcupdate.h>
#include <linux/module.h>
+#include <linux/kallsyms.h>
#include <asm/tlbflush.h>
struct kmem_cache *anon_vma_cachep;
-static inline void validate_anon_vma(struct vm_area_struct *find_vma)
-{
-#ifdef CONFIG_DEBUG_VM
- struct anon_vma *anon_vma = find_vma->anon_vma;
- struct vm_area_struct *vma;
- unsigned int mapcount = 0;
- int found = 0;
-
- list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {
- mapcount++;
- BUG_ON(mapcount > 100000);
- if (vma == find_vma)
- found = 1;
- }
- BUG_ON(!found);
-#endif
-}
-
/* This must be called under the mmap_sem. */
int anon_vma_prepare(struct vm_area_struct *vma)
{
{
struct anon_vma *anon_vma = vma->anon_vma;
- if (anon_vma) {
+ if (anon_vma)
list_add_tail(&vma->anon_vma_node, &anon_vma->head);
- validate_anon_vma(vma);
- }
}
void anon_vma_link(struct vm_area_struct *vma)
if (anon_vma) {
spin_lock(&anon_vma->lock);
list_add_tail(&vma->anon_vma_node, &anon_vma->head);
- validate_anon_vma(vma);
spin_unlock(&anon_vma->lock);
}
}
return;
spin_lock(&anon_vma->lock);
- validate_anon_vma(vma);
list_del(&vma->anon_vma_node);
/* We must garbage collect the anon_vma if it's empty */
static void anon_vma_ctor(void *data, struct kmem_cache *cachep,
unsigned long flags)
{
- if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
- SLAB_CTOR_CONSTRUCTOR) {
- struct anon_vma *anon_vma = data;
+ struct anon_vma *anon_vma = data;
- spin_lock_init(&anon_vma->lock);
- INIT_LIST_HEAD(&anon_vma->head);
- }
+ spin_lock_init(&anon_vma->lock);
+ INIT_LIST_HEAD(&anon_vma->head);
}
void __init anon_vma_init(void)
{
anon_vma_cachep = kmem_cache_create("anon_vma", sizeof(struct anon_vma),
- 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor, NULL);
+ 0, SLAB_DESTROY_BY_RCU|SLAB_PANIC, anon_vma_ctor);
}
/*
*/
static struct anon_vma *page_lock_anon_vma(struct page *page)
{
- struct anon_vma *anon_vma = NULL;
+ struct anon_vma *anon_vma;
unsigned long anon_mapping;
rcu_read_lock();
anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
spin_lock(&anon_vma->lock);
+ return anon_vma;
out:
rcu_read_unlock();
- return anon_vma;
+ return NULL;
+}
+
+static void page_unlock_anon_vma(struct anon_vma *anon_vma)
+{
+ spin_unlock(&anon_vma->lock);
+ rcu_read_unlock();
}
/*
if (!mapcount)
break;
}
- spin_unlock(&anon_vma->lock);
+
+ page_unlock_anon_vma(anon_vma);
return referenced;
}
{
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
- pte_t *pte, entry;
+ pte_t *pte;
spinlock_t *ptl;
int ret = 0;
if (!pte)
goto out;
- if (!pte_dirty(*pte) && !pte_write(*pte))
- goto unlock;
+ if (pte_dirty(*pte) || pte_write(*pte)) {
+ pte_t entry;
- entry = ptep_get_and_clear(mm, address, pte);
- entry = pte_mkclean(entry);
- entry = pte_wrprotect(entry);
- ptep_establish(vma, address, pte, entry);
- lazy_mmu_prot_update(entry);
- ret = 1;
+ flush_cache_page(vma, address, pte_pfn(*pte));
+ entry = ptep_clear_flush(vma, address, pte);
+ entry = pte_wrprotect(entry);
+ entry = pte_mkclean(entry);
+ set_pte_at(mm, address, pte, entry);
+ lazy_mmu_prot_update(entry);
+ ret = 1;
+ }
-unlock:
pte_unmap_unlock(pte, ptl);
out:
return ret;
struct address_space *mapping = page_mapping(page);
if (mapping)
ret = page_mkclean_file(mapping, page);
+ if (page_test_dirty(page)) {
+ page_clear_dirty(page);
+ ret = 1;
+ }
}
return ret;
}
+EXPORT_SYMBOL_GPL(page_mkclean);
/**
* page_set_anon_rmap - setup new anonymous rmap
}
/**
+ * page_set_anon_rmap - sanity check anonymous rmap addition
+ * @page: the page to add the mapping to
+ * @vma: the vm area in which the mapping is added
+ * @address: the user virtual address mapped
+ */
+static void __page_check_anon_rmap(struct page *page,
+ struct vm_area_struct *vma, unsigned long address)
+{
+#ifdef CONFIG_DEBUG_VM
+ /*
+ * The page's anon-rmap details (mapping and index) are guaranteed to
+ * be set up correctly at this point.
+ *
+ * We have exclusion against page_add_anon_rmap because the caller
+ * always holds the page locked, except if called from page_dup_rmap,
+ * in which case the page is already known to be setup.
+ *
+ * We have exclusion against page_add_new_anon_rmap because those pages
+ * are initially only visible via the pagetables, and the pte is locked
+ * over the call to page_add_new_anon_rmap.
+ */
+ struct anon_vma *anon_vma = vma->anon_vma;
+ anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
+ BUG_ON(page->mapping != (struct address_space *)anon_vma);
+ BUG_ON(page->index != linear_page_index(vma, address));
+#endif
+}
+
+/**
* page_add_anon_rmap - add pte mapping to an anonymous page
* @page: the page to add the mapping to
* @vma: the vm area in which the mapping is added
* @address: the user virtual address mapped
*
- * The caller needs to hold the pte lock.
+ * The caller needs to hold the pte lock and the page must be locked.
*/
void page_add_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
{
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
if (atomic_inc_and_test(&page->_mapcount))
__page_set_anon_rmap(page, vma, address);
- /* else checking page index and mapping is racy */
+ else
+ __page_check_anon_rmap(page, vma, address);
}
/*
*
* Same as page_add_anon_rmap but must only be called on *new* pages.
* This means the inc-and-test can be bypassed.
+ * Page does not have to be locked.
*/
void page_add_new_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
{
+ BUG_ON(address < vma->vm_start || address >= vma->vm_end);
atomic_set(&page->_mapcount, 0); /* elevate count by 1 (starts at -1) */
__page_set_anon_rmap(page, vma, address);
}
__inc_zone_page_state(page, NR_FILE_MAPPED);
}
+#ifdef CONFIG_DEBUG_VM
+/**
+ * page_dup_rmap - duplicate pte mapping to a page
+ * @page: the page to add the mapping to
+ *
+ * For copy_page_range only: minimal extract from page_add_file_rmap /
+ * page_add_anon_rmap, avoiding unnecessary tests (already checked) so it's
+ * quicker.
+ *
+ * The caller needs to hold the pte lock.
+ */
+void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
+{
+ BUG_ON(page_mapcount(page) == 0);
+ if (PageAnon(page))
+ __page_check_anon_rmap(page, vma, address);
+ atomic_inc(&page->_mapcount);
+}
+#endif
+
/**
* page_remove_rmap - take down pte mapping from a page
* @page: page to remove mapping from
*
* The caller needs to hold the pte lock.
*/
-void page_remove_rmap(struct page *page)
+void page_remove_rmap(struct page *page, struct vm_area_struct *vma)
{
if (atomic_add_negative(-1, &page->_mapcount)) {
-#ifdef CONFIG_DEBUG_VM
if (unlikely(page_mapcount(page) < 0)) {
printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
+ printk (KERN_EMERG " page pfn = %lx\n", page_to_pfn(page));
printk (KERN_EMERG " page->flags = %lx\n", page->flags);
printk (KERN_EMERG " page->count = %x\n", page_count(page));
printk (KERN_EMERG " page->mapping = %p\n", page->mapping);
+ print_symbol (KERN_EMERG " vma->vm_ops = %s\n", (unsigned long)vma->vm_ops);
+ if (vma->vm_ops) {
+ print_symbol (KERN_EMERG " vma->vm_ops->nopage = %s\n", (unsigned long)vma->vm_ops->nopage);
+ print_symbol (KERN_EMERG " vma->vm_ops->fault = %s\n", (unsigned long)vma->vm_ops->fault);
+ }
+ if (vma->vm_file && vma->vm_file->f_op)
+ print_symbol (KERN_EMERG " vma->vm_file->f_op->mmap = %s\n", (unsigned long)vma->vm_file->f_op->mmap);
+ BUG();
}
-#endif
- BUG_ON(page_mapcount(page) < 0);
+
/*
* It would be tidy to reset the PageAnon mapping here,
* but that might overwrite a racing page_add_anon_rmap
* Leaving it set also helps swapoff to reinstate ptes
* faster for those pages still in swapcache.
*/
- if (page_test_and_clear_dirty(page))
+ if (page_test_dirty(page)) {
+ page_clear_dirty(page);
set_page_dirty(page);
+ }
__dec_zone_page_state(page,
PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED);
}
dec_mm_counter(mm, file_rss);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
page_cache_release(page);
out_unmap:
if (pte_dirty(pteval))
set_page_dirty(page);
- page_remove_rmap(page);
+ page_remove_rmap(page, vma);
page_cache_release(page);
dec_mm_counter(mm, file_rss);
(*mapcount)--;
if (ret == SWAP_FAIL || !page_mapped(page))
break;
}
- spin_unlock(&anon_vma->lock);
+
+ page_unlock_anon_vma(anon_vma);
return ret;
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff