Merge tag 'omapdss-for-3.7' of git://gitorious.org/linux-omap-dss2/linux into fbdev-next

Omapdss driver changes for the 3.7 merge window.

Notable changes:

* Basic writeback support for DISPC level. Writeback is not yet usable, though,
  as we need higher level code to actually expose the writeback feature to
  userspace.
* Rewriting the omapdss output drivers. We're trying to remove the hard links
  between the omapdss and the panels, and this rewrite work moves us closer to
  that goal.
* Cleanup and restructuring patches that have been made while working on device
  tree support for omapdss. Device tree support is still some way ahead, but
  these patches are good cleanups in themselves.
* Basic OMAP5 DSS support for DPI and DSI outputs.
* Workaround for the problem that GFX overlay's fifo is too small for high
  resolution scenarios, causing underflows.
* Cleanups that remove dependencies to omap platform code.

1 files changed, 30 insertions, 36 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index 9f6d2e41281d..58e2e7b77372 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -914,7 +914,7 @@ link_dev_buffers(struct page *page, struct buffer_head *head)
 /*
  * Initialise the state of a blockdev page's buffers.
  */ 
-static void
+static sector_t
 init_page_buffers(struct page *page, struct block_device *bdev,
                         sector_t block, int size)
 {
@@ -936,33 +936,41 @@ init_page_buffers(struct page *page, struct block_device *bdev,
                 block++;
                 bh = bh->b_this_page;
         } while (bh != head);
+
+        /*
+         * Caller needs to validate requested block against end of device.
+         */
+        return end_block;
 }
 
 /*
  * Create the page-cache page that contains the requested block.
  *
- * This is user purely for blockdev mappings.
+ * This is used purely for blockdev mappings.
  */
-static struct page *
+static int
 grow_dev_page(struct block_device *bdev, sector_t block,
-                pgoff_t index, int size)
+                pgoff_t index, int size, int sizebits)
 {
         struct inode *inode = bdev->bd_inode;
         struct page *page;
         struct buffer_head *bh;
+        sector_t end_block;
+        int ret = 0;            /* Will call free_more_memory() */
 
         page = find_or_create_page(inode->i_mapping, index,
                 (mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS)|__GFP_MOVABLE);
         if (!page)
-                return NULL;
+                return ret;
 
         BUG_ON(!PageLocked(page));
 
         if (page_has_buffers(page)) {
                 bh = page_buffers(page);
                 if (bh->b_size == size) {
-                        init_page_buffers(page, bdev, block, size);
-                        return page;
+                        end_block = init_page_buffers(page, bdev,
+                                                index << sizebits, size);
+                        goto done;
                 }
                 if (!try_to_free_buffers(page))
                         goto failed;
@@ -982,14 +990,14 @@ grow_dev_page(struct block_device *bdev, sector_t block,
          */
         spin_lock(&inode->i_mapping->private_lock);
         link_dev_buffers(page, bh);
-        init_page_buffers(page, bdev, block, size);
+        end_block = init_page_buffers(page, bdev, index << sizebits, size);
         spin_unlock(&inode->i_mapping->private_lock);
-        return page;
-
+done:
+        ret = (block < end_block) ? 1 : -ENXIO;
 failed:
         unlock_page(page);
         page_cache_release(page);
-        return NULL;
+        return ret;
 }
 
 /*
@@ -999,7 +1007,6 @@ failed:
 static int
 grow_buffers(struct block_device *bdev, sector_t block, int size)
 {
-        struct page *page;
         pgoff_t index;
         int sizebits;
 
@@ -1023,22 +1030,14 @@ grow_buffers(struct block_device *bdev, sector_t block, int size)
                         bdevname(bdev, b));
                 return -EIO;
         }
-        block = index << sizebits;
+
         /* Create a page with the proper size buffers.. */
-        page = grow_dev_page(bdev, block, index, size);
-        if (!page)
-                return 0;
-        unlock_page(page);
-        page_cache_release(page);
-        return 1;
+        return grow_dev_page(bdev, block, index, size, sizebits);
 }
 
 static struct buffer_head *
 __getblk_slow(struct block_device *bdev, sector_t block, int size)
 {
-        int ret;
-        struct buffer_head *bh;
-
         /* Size must be multiple of hard sectorsize */
         if (unlikely(size & (bdev_logical_block_size(bdev)-1) ||
                         (size < 512 || size > PAGE_SIZE))) {
@@ -1051,21 +1050,20 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size)
                 return NULL;
         }
 
-retry:
-        bh = __find_get_block(bdev, block, size);
-        if (bh)
-                return bh;
+        for (;;) {
+                struct buffer_head *bh;
+                int ret;
 
-        ret = grow_buffers(bdev, block, size);
-        if (ret == 0) {
-                free_more_memory();
-                goto retry;
-        } else if (ret > 0) {
                 bh = __find_get_block(bdev, block, size);
                 if (bh)
                         return bh;
+
+                ret = grow_buffers(bdev, block, size);
+                if (ret < 0)
+                        return NULL;
+                if (ret == 0)
+                        free_more_memory();
         }
-        return NULL;
 }
 
 /*
@@ -1321,10 +1319,6 @@ EXPORT_SYMBOL(__find_get_block);
  * which corresponds to the passed block_device, block and size. The
  * returned buffer has its reference count incremented.
  *
- * __getblk() cannot fail - it just keeps trying.  If you pass it an
- * illegal block number, __getblk() will happily return a buffer_head
- * which represents the non-existent block.  Very weird.
- *
  * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers()
  * attempt is failing.  FIXME, perhaps?
  */