mm: implement ->map_pages for page cache
[linux.git] / mm / filemap.c
index d6df3bacb0fbe38bbacb6a81b3399391e4455ba3..3f9b5fbb623fae2adef7d74adae65775b1a99666 100644 (file)
@@ -33,6 +33,7 @@
 #include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
 #include <linux/memcontrol.h>
 #include <linux/cleancache.h>
+#include <linux/rmap.h>
 #include "internal.h"
 
 #define CREATE_TRACE_POINTS
@@ -2064,6 +2065,78 @@ page_not_uptodate:
 }
 EXPORT_SYMBOL(filemap_fault);
 
+void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+       struct radix_tree_iter iter;
+       void **slot;
+       struct file *file = vma->vm_file;
+       struct address_space *mapping = file->f_mapping;
+       loff_t size;
+       struct page *page;
+       unsigned long address = (unsigned long) vmf->virtual_address;
+       unsigned long addr;
+       pte_t *pte;
+
+       rcu_read_lock();
+       radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, vmf->pgoff) {
+               if (iter.index > vmf->max_pgoff)
+                       break;
+repeat:
+               page = radix_tree_deref_slot(slot);
+               if (unlikely(!page))
+                       goto next;
+               if (radix_tree_exception(page)) {
+                       if (radix_tree_deref_retry(page))
+                               break;
+                       else
+                               goto next;
+               }
+
+               if (!page_cache_get_speculative(page))
+                       goto repeat;
+
+               /* Has the page moved? */
+               if (unlikely(page != *slot)) {
+                       page_cache_release(page);
+                       goto repeat;
+               }
+
+               if (!PageUptodate(page) ||
+                               PageReadahead(page) ||
+                               PageHWPoison(page))
+                       goto skip;
+               if (!trylock_page(page))
+                       goto skip;
+
+               if (page->mapping != mapping || !PageUptodate(page))
+                       goto unlock;
+
+               size = i_size_read(mapping->host) + PAGE_CACHE_SIZE - 1;
+               if (page->index >= size >> PAGE_CACHE_SHIFT)
+                       goto unlock;
+
+               pte = vmf->pte + page->index - vmf->pgoff;
+               if (!pte_none(*pte))
+                       goto unlock;
+
+               if (file->f_ra.mmap_miss > 0)
+                       file->f_ra.mmap_miss--;
+               addr = address + (page->index - vmf->pgoff) * PAGE_SIZE;
+               do_set_pte(vma, addr, page, pte, false, false);
+               unlock_page(page);
+               goto next;
+unlock:
+               unlock_page(page);
+skip:
+               page_cache_release(page);
+next:
+               if (iter.index == vmf->max_pgoff)
+                       break;
+       }
+       rcu_read_unlock();
+}
+EXPORT_SYMBOL(filemap_map_pages);
+
 int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
        struct page *page = vmf->page;
@@ -2093,6 +2166,7 @@ EXPORT_SYMBOL(filemap_page_mkwrite);
 
 const struct vm_operations_struct generic_file_vm_ops = {
        .fault          = filemap_fault,
+       .map_pages      = filemap_map_pages,
        .page_mkwrite   = filemap_page_mkwrite,
        .remap_pages    = generic_file_remap_pages,
 };
@@ -2133,6 +2207,18 @@ int generic_file_readonly_mmap(struct file * file, struct vm_area_struct * vma)
 EXPORT_SYMBOL(generic_file_mmap);
 EXPORT_SYMBOL(generic_file_readonly_mmap);
 
+static struct page *wait_on_page_read(struct page *page)
+{
+       if (!IS_ERR(page)) {
+               wait_on_page_locked(page);
+               if (!PageUptodate(page)) {
+                       page_cache_release(page);
+                       page = ERR_PTR(-EIO);
+               }
+       }
+       return page;
+}
+
 static struct page *__read_cache_page(struct address_space *mapping,
                                pgoff_t index,
                                int (*filler)(void *, struct page *),
@@ -2159,6 +2245,8 @@ repeat:
                if (err < 0) {
                        page_cache_release(page);
                        page = ERR_PTR(err);
+               } else {
+                       page = wait_on_page_read(page);
                }
        }
        return page;
@@ -2195,6 +2283,10 @@ retry:
        if (err < 0) {
                page_cache_release(page);
                return ERR_PTR(err);
+       } else {
+               page = wait_on_page_read(page);
+               if (IS_ERR(page))
+                       return page;
        }
 out:
        mark_page_accessed(page);
@@ -2202,40 +2294,25 @@ out:
 }
 
 /**
- * read_cache_page_async - read into page cache, fill it if needed
+ * read_cache_page - read into page cache, fill it if needed
  * @mapping:   the page's address_space
  * @index:     the page index
  * @filler:    function to perform the read
  * @data:      first arg to filler(data, page) function, often left as NULL
  *
- * Same as read_cache_page, but don't wait for page to become unlocked
- * after submitting it to the filler.
- *
  * Read into the page cache. If a page already exists, and PageUptodate() is
- * not set, try to fill the page but don't wait for it to become unlocked.
+ * not set, try to fill the page and wait for it to become unlocked.
  *
  * If the page does not get brought uptodate, return -EIO.
  */
-struct page *read_cache_page_async(struct address_space *mapping,
+struct page *read_cache_page(struct address_space *mapping,
                                pgoff_t index,
                                int (*filler)(void *, struct page *),
                                void *data)
 {
        return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping));
 }
-EXPORT_SYMBOL(read_cache_page_async);
-
-static struct page *wait_on_page_read(struct page *page)
-{
-       if (!IS_ERR(page)) {
-               wait_on_page_locked(page);
-               if (!PageUptodate(page)) {
-                       page_cache_release(page);
-                       page = ERR_PTR(-EIO);
-               }
-       }
-       return page;
-}
+EXPORT_SYMBOL(read_cache_page);
 
 /**
  * read_cache_page_gfp - read into page cache, using specified page allocation flags.
@@ -2254,31 +2331,10 @@ struct page *read_cache_page_gfp(struct address_space *mapping,
 {
        filler_t *filler = (filler_t *)mapping->a_ops->readpage;
 
-       return wait_on_page_read(do_read_cache_page(mapping, index, filler, NULL, gfp));
+       return do_read_cache_page(mapping, index, filler, NULL, gfp);
 }
 EXPORT_SYMBOL(read_cache_page_gfp);
 
-/**
- * read_cache_page - read into page cache, fill it if needed
- * @mapping:   the page's address_space
- * @index:     the page index
- * @filler:    function to perform the read
- * @data:      first arg to filler(data, page) function, often left as NULL
- *
- * Read into the page cache. If a page already exists, and PageUptodate() is
- * not set, try to fill the page then wait for it to become unlocked.
- *
- * If the page does not get brought uptodate, return -EIO.
- */
-struct page *read_cache_page(struct address_space *mapping,
-                               pgoff_t index,
-                               int (*filler)(void *, struct page *),
-                               void *data)
-{
-       return wait_on_page_read(read_cache_page_async(mapping, index, filler, data));
-}
-EXPORT_SYMBOL(read_cache_page);
-
 static size_t __iovec_copy_from_user_inatomic(char *vaddr,
                        const struct iovec *iov, size_t base, size_t bytes)
 {