mtd: gpmi: make blockmark swapping optional

[karo-tx-linux.git] / fs / block_dev.c

diff --git a/fs/block_dev.c b/fs/block_dev.c
index e68e150b1b163c15da172cfa60ed832d14841495..6d7274619bf916c2dcf0d7744ba8d888d948d711 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -364,6 +364,69 @@ int blkdev_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
 }
 EXPORT_SYMBOL(blkdev_fsync);
 
+/**
+ * bdev_read_page() - Start reading a page from a block device
+ * @bdev: The device to read the page from
+ * @sector: The offset on the device to read the page to (need not be aligned)
+ * @page: The page to read
+ *
+ * On entry, the page should be locked.  It will be unlocked when the page
+ * has been read.  If the block driver implements rw_page synchronously,
+ * that will be true on exit from this function, but it need not be.
+ *
+ * Errors returned by this function are usually "soft", eg out of memory, or
+ * queue full; callers should try a different route to read this page rather
+ * than propagate an error back up the stack.
+ *
+ * Return: negative errno if an error occurs, 0 if submission was successful.
+ */
+int bdev_read_page(struct block_device *bdev, sector_t sector,
+                       struct page *page)
+{
+       const struct block_device_operations *ops = bdev->bd_disk->fops;
+       if (!ops->rw_page)
+               return -EOPNOTSUPP;
+       return ops->rw_page(bdev, sector + get_start_sect(bdev), page, READ);
+}
+EXPORT_SYMBOL_GPL(bdev_read_page);
+
+/**
+ * bdev_write_page() - Start writing a page to a block device
+ * @bdev: The device to write the page to
+ * @sector: The offset on the device to write the page to (need not be aligned)
+ * @page: The page to write
+ * @wbc: The writeback_control for the write
+ *
+ * On entry, the page should be locked and not currently under writeback.
+ * On exit, if the write started successfully, the page will be unlocked and
+ * under writeback.  If the write failed already (eg the driver failed to
+ * queue the page to the device), the page will still be locked.  If the
+ * caller is a ->writepage implementation, it will need to unlock the page.
+ *
+ * Errors returned by this function are usually "soft", eg out of memory, or
+ * queue full; callers should try a different route to write this page rather
+ * than propagate an error back up the stack.
+ *
+ * Return: negative errno if an error occurs, 0 if submission was successful.
+ */
+int bdev_write_page(struct block_device *bdev, sector_t sector,
+                       struct page *page, struct writeback_control *wbc)
+{
+       int result;
+       int rw = (wbc->sync_mode == WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
+       const struct block_device_operations *ops = bdev->bd_disk->fops;
+       if (!ops->rw_page)
+               return -EOPNOTSUPP;
+       set_page_writeback(page);
+       result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);
+       if (result)
+               end_page_writeback(page);
+       else
+               unlock_page(page);
+       return result;
+}
+EXPORT_SYMBOL_GPL(bdev_write_page);
+
 /*
  * pseudo-fs
  */