Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/pci-2.6

[powerpc.git] / mm / readahead.c

diff --git a/mm/readahead.c b/mm/readahead.c
index d0b5003..8d6eeaa 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -158,7 +158,7 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 {
        unsigned page_idx;
        struct pagevec lru_pvec;
-       int ret = 0;
+       int ret;
 
        if (mapping->a_ops->readpages) {
                ret = mapping->a_ops->readpages(filp, mapping, pages, nr_pages);
@@ -171,14 +171,17 @@ static int read_pages(struct address_space *mapping, struct file *filp,
                list_del(&page->lru);
                if (!add_to_page_cache(page, mapping,
                                        page->index, GFP_KERNEL)) {
-                       mapping->a_ops->readpage(filp, page);
-                       if (!pagevec_add(&lru_pvec, page))
-                               __pagevec_lru_add(&lru_pvec);
-               } else {
-                       page_cache_release(page);
+                       ret = mapping->a_ops->readpage(filp, page);
+                       if (ret != AOP_TRUNCATED_PAGE) {
+                               if (!pagevec_add(&lru_pvec, page))
+                                       __pagevec_lru_add(&lru_pvec);
+                               continue;
+                       } /* else fall through to release */
                }
+               page_cache_release(page);
        }
        pagevec_lru_add(&lru_pvec);
+       ret = 0;
 out:
        return ret;
 }
@@ -254,7 +257,7 @@ out:
  */
 static int
 __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
-                       unsigned long offset, unsigned long nr_to_read)
+                       pgoff_t offset, unsigned long nr_to_read)
 {
        struct inode *inode = mapping->host;
        struct page *page;
@@ -274,7 +277,7 @@ __do_page_cache_readahead(struct address_space *mapping, struct file *filp,
         */
        read_lock_irq(&mapping->tree_lock);
        for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
-               unsigned long page_offset = offset + page_idx;
+               pgoff_t page_offset = offset + page_idx;
                
                if (page_offset > end_index)
                        break;
@@ -311,7 +314,7 @@ out:
  * memory at once.
  */
 int force_page_cache_readahead(struct address_space *mapping, struct file *filp,
-               unsigned long offset, unsigned long nr_to_read)
+               pgoff_t offset, unsigned long nr_to_read)
 {
        int ret = 0;
 
@@ -368,7 +371,7 @@ static inline int check_ra_success(struct file_ra_state *ra,
  * request queues.
  */
 int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
-                       unsigned long offset, unsigned long nr_to_read)
+                       pgoff_t offset, unsigned long nr_to_read)
 {
        if (bdi_read_congested(mapping->backing_dev_info))
                return -1;
@@ -385,7 +388,7 @@ int do_page_cache_readahead(struct address_space *mapping, struct file *filp,
  */
 static int
 blockable_page_cache_readahead(struct address_space *mapping, struct file *filp,
-                       unsigned long offset, unsigned long nr_to_read,
+                       pgoff_t offset, unsigned long nr_to_read,
                        struct file_ra_state *ra, int block)
 {
        int actual;
@@ -430,14 +433,27 @@ static int make_ahead_window(struct address_space *mapping, struct file *filp,
        return ret;
 }
 
-/*
- * page_cache_readahead is the main function.  If performs the adaptive
+/**
+ * page_cache_readahead - generic adaptive readahead
+ * @mapping: address_space which holds the pagecache and I/O vectors
+ * @ra: file_ra_state which holds the readahead state
+ * @filp: passed on to ->readpage() and ->readpages()
+ * @offset: start offset into @mapping, in PAGE_CACHE_SIZE units
+ * @req_size: hint: total size of the read which the caller is performing in
+ *            PAGE_CACHE_SIZE units
+ *
+ * page_cache_readahead() is the main function.  If performs the adaptive
  * readahead window size management and submits the readahead I/O.
+ *
+ * Note that @filp is purely used for passing on to the ->readpage[s]()
+ * handler: it may refer to a different file from @mapping (so we may not use
+ * @filp->f_mapping or @filp->f_dentry->d_inode here).
+ * Also, @ra may not be equal to &@filp->f_ra.
+ *
  */
 unsigned long
 page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra,
-                    struct file *filp, unsigned long offset,
-                    unsigned long req_size)
+                    struct file *filp, pgoff_t offset, unsigned long req_size)
 {
        unsigned long max, newsize;
        int sequential;