[PATCH] i4l make PCMCIA for all cards working with shared IRQ

[pandora-kernel.git] / mm / truncate.c

diff --git a/mm/truncate.c b/mm/truncate.c
index 9173ab5..cf1b015 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -82,12 +82,15 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
 }
 
 /**
- * truncate_inode_pages - truncate *all* the pages from an offset
+ * truncate_inode_pages - truncate range of pages specified by start and
+ * end byte offsets
  * @mapping: mapping to truncate
  * @lstart: offset from which to truncate
+ * @lend: offset to which to truncate
  *
- * Truncate the page cache at a set offset, removing the pages that are beyond
- * that offset (and zeroing out partial pages).
+ * Truncate the page cache, removing the pages that are between
+ * specified offsets (and zeroing out partial page
+ * (if lstart is not page aligned)).
  *
  * Truncate takes two passes - the first pass is nonblocking.  It will not
  * block on page locks and it will not block on writeback.  The second pass
@@ -101,12 +104,12 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
  * We pass down the cache-hot hint to the page freeing code.  Even if the
  * mapping is large, it is probably the case that the final pages are the most
  * recently touched, and freeing happens in ascending file offset order.
- *
- * Called under (and serialised by) inode->i_sem.
  */
-void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
+void truncate_inode_pages_range(struct address_space *mapping,
+                               loff_t lstart, loff_t lend)
 {
        const pgoff_t start = (lstart + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT;
+       pgoff_t end;
        const unsigned partial = lstart & (PAGE_CACHE_SIZE - 1);
        struct pagevec pvec;
        pgoff_t next;
@@ -115,13 +118,22 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
        if (mapping->nrpages == 0)
                return;
 
+       BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1));
+       end = (lend >> PAGE_CACHE_SHIFT);
+
        pagevec_init(&pvec, 0);
        next = start;
-       while (pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
+       while (next <= end &&
+              pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];
                        pgoff_t page_index = page->index;
 
+                       if (page_index > end) {
+                               next = page_index;
+                               break;
+                       }
+
                        if (page_index > next)
                                next = page_index;
                        next++;
@@ -157,9 +169,15 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
                        next = start;
                        continue;
                }
+               if (pvec.pages[0]->index > end) {
+                       pagevec_release(&pvec);
+                       break;
+               }
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];
 
+                       if (page->index > end)
+                               break;
                        lock_page(page);
                        wait_on_page_writeback(page);
                        if (page->index > next)
@@ -171,7 +189,19 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
                pagevec_release(&pvec);
        }
 }
+EXPORT_SYMBOL(truncate_inode_pages_range);
 
+/**
+ * truncate_inode_pages - truncate *all* the pages from an offset
+ * @mapping: mapping to truncate
+ * @lstart: offset from which to truncate
+ *
+ * Called under (and serialised by) inode->i_mutex.
+ */
+void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
+{
+       truncate_inode_pages_range(mapping, lstart, (loff_t)-1);
+}
 EXPORT_SYMBOL(truncate_inode_pages);
 
 /**
@@ -200,14 +230,24 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
                        pagevec_lookup(&pvec, mapping, next, PAGEVEC_SIZE)) {
                for (i = 0; i < pagevec_count(&pvec); i++) {
                        struct page *page = pvec.pages[i];
+                       pgoff_t index;
+                       int lock_failed;
 
-                       if (TestSetPageLocked(page)) {
-                               next++;
-                               continue;
-                       }
-                       if (page->index > next)
-                               next = page->index;
+                       lock_failed = TestSetPageLocked(page);
+
+                       /*
+                        * We really shouldn't be looking at the ->index of an
+                        * unlocked page.  But we're not allowed to lock these
+                        * pages.  So we rely upon nobody altering the ->index
+                        * of this (pinned-by-us) page.
+                        */
+                       index = page->index;
+                       if (index > next)
+                               next = index;
                        next++;
+                       if (lock_failed)
+                               continue;
+
                        if (PageDirty(page) || PageWriteback(page))
                                goto unlock;
                        if (page_mapped(page))
@@ -219,7 +259,6 @@ unlock:
                                break;
                }
                pagevec_release(&pvec);
-               cond_resched();
        }
        return ret;
 }