lib/xarray: introduce a new helper xas_get_order

It can be used after xas_load to check the order of loaded entries. 
Compared to xa_get_order, it saves an XA_STATE and avoid a rewalk.

Added new test for xas_get_order, to make the test work, we have to export
xas_get_order with EXPORT_SYMBOL_GPL.

Also fix a sparse warning by checking the slot value with xa_entry instead
of accessing it directly, as suggested by Matthew Wilcox.

[[email protected]: simplify comment, sparse warning fix, per Matthew Wilcox]
  Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kairui Song <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions