[bug report] fs/block_dev.c: add bdev_read_page() and bdev_write_page()

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Matthew Wilcox,

The patch 47a191fd38eb: "fs/block_dev.c: add bdev_read_page() and
bdev_write_page()" from Jun 4, 2014, leads to the following static
checker warning:

	include/linux/genhd.h:382 part_inc_in_flight()
	warn: buffer overflow 'part->in_flight' 2 <= 72

include/linux/genhd.h
   380  static inline void part_inc_in_flight(struct hd_struct *part, int rw)
   381  {
   382          atomic_inc(&part->in_flight[rw]);
                                            ^^
This should either be READ or WRITE.

   383          if (part->partno)
   384                  atomic_inc(&part_to_disk(part)->part0.in_flight[rw]);
   385  }


   444  int bdev_write_page(struct block_device *bdev, sector_t sector,
   445                          struct page *page, struct writeback_control *wbc)
   446  {
   447          int result;
   448          int rw = (wbc->sync_mode = WB_SYNC_ALL) ? WRITE_SYNC : WRITE;
                                                           ^^^^^^^^^^
But here we're setting it to WRITE_SYNC.

   449          const struct block_device_operations *ops = bdev->bd_disk->fops;
   450  
   451          if (!ops->rw_page || bdev_get_integrity(bdev))
   452                  return -EOPNOTSUPP;
   453          result = blk_queue_enter(bdev->bd_queue, false);
   454          if (result)
   455                  return result;
   456  
   457          set_page_writeback(page);
   458          result = ops->rw_page(bdev, sector + get_start_sect(bdev), page, rw);
   459          if (result)
   460                  end_page_writeback(page);
   461          else
   462                  unlock_page(page);
   463          blk_queue_exit(bdev->bd_queue);
   464          return result;
   465  }

regards,
dan carpenter